Cognitive costs of captivity: hatchery-reared marbled rockfish have impaired spatial cognition

Cognitive costs of captivity: hatchery-reared marbled rockfish have impaired spatial cognition | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Cognitive costs of captivity: hatchery-reared marbled rockfish have impaired spatial cognition Chenhang Lv, Haoyu Guo, Yingying Ou, Joacim Näslund, Yuling Hong, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8422304/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 8 You are reading this latest preprint version Abstract Hatchery-reared fish typically display marked behavioral differences compared to wild conspecifics. For reef-dwelling species, spatial cognition is critical to navigate complex and dynamic habitats. If captive rearing influences these abilities in fish reared for release into nature, then optimization of rearing environments and practices may be necessary. We compared hatchery-reared and wild marbled rockfish ( Sebastiscus marmoratus ) in laboratory spatial cognition tests aimed at investigating differences in navigation strategies, behavioral lateralization, and cognitive flexibility. These tests were complemented by neuroanatomical analyses of brain regions involved in spatial processing. Hatchery-reared fish showed no consistent turning directionality, whereas wild fish had a general population-level lateralization (right-turning bias). In maze tests, wild fish navigated significantly faster and achieved higher success rates than hatchery fish. During reversal learning, wild fish adapted more efficiently, demonstrating better cognitive flexibility. Both hatchery-reared and wild fish predominantly relied on egocentric (turn-based) strategies, with limited use of allocentric (landmark-based) cues. No significant differences were detected in the relative volumes of the telencephalon or cerebellum, or in neuronal density. These findings indicate that captive rearing can impair spatial cognition and behavioral flexibility in fish, which could reduce environmental adaptability and may help explain the poor post-release survival of hatchery-reared reef species. Sebastiscus marmoratus behavioral lateralization spatial cognition cognitive flexibility brain morphology Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 INTRODUCTION Many studies have demonstrated significant behavioral divergences between hatchery-reared fish and their wild conspecifics, with well-documented differences in predator avoidance, social interactions, prey recognition, capture efficiency, and territoriality (Lorenzen et al., 2012 ). For instance, hatchery-reared brown trout ( Salmo trutta ) display less consistent exploratory strategies in novel environments and require more time to acquire novel prey-capture skills than wild trout (Sundström and Johnsson, 2001 ; Adriaenssens and Johnsson, 2011 ). Such behavioral deviations may reduce environmental adaptability and contribute to low post-release survival (Johnsson et al., 2014 ). Spatial cognition (i.e. the acquisition, organization, and application of spatial information to navigate and interpret environmental structure) involves learning, memory, and the use of three-dimensional environmental cues for navigation (Poucet, 1993 ). Substantial inter- and intraspecific variation has been documented across fish taxa. For example, male guppies ( Poecilia reticulata ) outperform females in spatial learning tasks (Lucon-Xiccato and Bisazza, 2017 ), zebrafish ( Danio rerio ) show stage-dependent cognitive performance during development (Valente et al., 2012 ), and multiple species differ in detour task performance (Sovrano et al., 2018 ). These findings establish sex, age, and species identity as important determinants of spatial cognition. Beyond intrinsic factors, environmental factors are also identified as important for spatial cognition. In climbing perch ( Anabas testudineus ) maze trials, pond-dwelling individuals rely more on landmark cues, while river-dwelling individuals favor egocentric strategies (Sheenaja and Thomas, 2011 ). Ecotype differences in broadstripe gobies ( Elacatinus prochilos) also influence spatial learning (Mazzei et al., 2019 ). In captive environments, environmental enrichment has, in some cases, been shown to promote brain size development, suggesting that the simplified, stimulus-poor conditions of aquaculture may inhibit neural and cognitive development (Näslund, 2021 ). In rocky reef habitats, a well-developed spatial cognitive ability is likely a key adaptation enabling reef-dwelling species to thrive in the complex environment. Consequently, deficits in spatial abilities may help explain the poor post-release survival of hatchery-reared reef species. The marbled rockfish ( Sebastiscus marmoratus ) is an economically important species with a distribution in the coastal areas of China, Japan and Korea. It is a typical reef-dwelling species, widely distributed in nearshore rocky reef areas and is among the most popular recreational fish targets in Eastern Asia (Sun et al., 2024; Wu, 1999 ; Wang et al., 2019 ). From 2018 to 2021, approximately 500,000 marbled rockfish were released into coastal waters of the Zhejiang Province (Chen et al., 2022 ). However, previous studies indicate that hatchery-reared reef fish, including marbled rockfish, differ significantly from wild conspecifics in key traits, potentially compromising their post-release survival (Guo et al., 2022 ; Qi et al., 2024 ). Despite recognition of spatial cognition as a vital survival trait for reef-dwelling fish (Pillans et al., 2014 ), differences between hatchery-reared and wild individuals, as well as the neural mechanisms underlying such variation, remain poorly understood. Here, we aimed to systematically compare spatial cognition, strategy use, lateralization, and cognitive flexibility between hatchery-reared and wild marbled rockfish using a maze setup, and we preliminarily examined the neurobiological basis underlying these differences. A general hypothesis of hatchery environment impairing cognition was used, with matching predictions of lower test performance in hatchery-reared individuals compared with wild conspecifics. METHODS Experimental Animals and Holding Conditions All hatchery-reared marbled rockfish used in this study were the progeny of wild-caught fish captured from the waters near Dongji Island, Zhoushan, China (30°12′N, 122°40′E). The hatchery-reared population used for this study was produced in January 2020 and then reared in nursery ponds (size: 5 m × 6 m × 1 m) in a commercial hatchery (Xixuan Technology Island) in Zhoushan, according to the standard methodology for the intensive culture of this species. The nursery ponds received a continuous flow of sand-filtered natural seawater (flow rate: 2 m³/h), gently aerated by air-stone diffusers. Water temperature was maintained between 23 and 25°C, with stocking densities ranging from 5,000 to 10,000 individuals per cubic meter. During the hatchery phase, fish were fed a commercial pellet diet (Hayashikane Sangyo, Co., Ltd., Yamaguchi Prefecture, Japan; composition: crude protein ≥ 50.0%, lipid ≥ 6.0%, fiber ≤ 3.0%, and ash ≤ 17.0%). In early December 2022, 30 hatchery-reared individuals of near-uniform size (total length: 8.02 ± 0.91 cm, mean ± SD) were selected and transferred to the Laboratory of Marine Ranching Stock Enhancement (LMRSE), Zhejiang University. They were acclimated in circular tanks (water volume: 1,780 L; inner diameter: 1.6 m; height: 0.8 m) equipped with a recirculating seawater system. During acclimation, water temperature was maintained constant at 17°C, consistent with the concurrent ambient sea temperature (water quality parameters: dissolved oxygen ≥ 6.0 mg/L, unionized ammonia < 0.05 mg/L, salinity = 28‰, pH ranging 8.0–8.3). A photoperiod of 11 h light:13 h dark was implemented. Starting on the third day post-transport, fish were fed twice daily (at 09:00 and 18:00) to apparent satiation with commercial dry pellets (as above). Uneaten food and waste were removed by siphoning one hour after feeding. Wild marbled rockfish were captured by angling in December 2023, in the waters surrounding Dongji Island (30°43′ N, 122°46′ E). Thereby, the hatchery-reared and wild-caught fish likely belong to the same genetic stocks. Thirty wild marbled rockfish of uniform size (total body length: 8.19 ± 0.97 cm, mean ± SD) were selected and transported to a circular holding tank (water volume: 1780 L; inside diameter: 1.60 m; height: 0.80 m) equipped with a seawater circulation system at the Marine Ranching and Fishery Carbon Sink Ecological Function Innovation Laboratory (MRFCSEFIL) of Zhejiang Ocean University. The dimensions and water conditions of the holding tank for wild fish were identical to those of the tank for hatchery-reared fish, as both tanks were part of the same recirculating seawater system. To mimic natural conditions, shelter structures (plastic tubes) were introduced into the holding tank as environmental enrichment. Beginning on the third day after transport, the wild fish were fed live ridgetail white prawns ( Exopalaemon carinicauda ) every other day to ensure a constant supply of live prey in the tank. The Institutional Animal Care and Use Committee at Zhejiang Ocean University approved all animal housing and experimental procedures (No. 2022016). During the experiment, all fish were treated according to the Guide for the Care and Use of Laboratory Animals. Apparatus A double-door maze apparatus was designed and constructed based on protocols established by Girvan & Braithwaite ( 1998 ) and Makino et al. ( 2015 ). The apparatus consisted of a rectangular glass tank (67 cm long × 37 cm wide), internally divided into a start zone, a choice zone, an interaction zone, and an attraction zone (Fig. 1 ). All trials were filmed from above using a high-definition camera (Hikvision; Hangzhou, Zhejiang, China). A removable transparent partition separated the start zone from the choice zone. An opaque acrylic partition was placed between the choice zone and the attraction zone. This partition featured two openings, each of which could be opened or closed independently. During the experiments, one opening remained open, serving as the sole correct exit (the goal), while the other was closed (blocked by a transparent acrylic board). A small opaque acrylic divider was positioned between the two openings. A transparent acrylic panel was installed between the attraction zone and the interaction zone to prevent fish in the attraction zone from leaving. The attraction zone contained five marbled rockfish, which served as a social attraction (preliminary experiments had confirmed the effectiveness of this conspecific grouping as an attractant). To further enhance the attraction effect, red light was provided above the attraction and interaction zones via a red filter. This approach was based on preliminary experiments that verified strong positive phototaxis to red light in the study species (also see Qi et al. 2024 ). Experimental Pretraining Protocol Following a 7-day acclimation period in the holding tanks, 24 fish were randomly selected from each of the hatchery-reared and wild groups for pre-training. The selected fish from each group were introduced into each of the two identical experimental apparatuses to familiarize them with the internal structures, with six fish being assigned to each apparatus. During this pre-training phase, the start zone was fully accessible, and both openings in the acrylic partition between the choice zone and the interaction zone were left open. The fish were allowed to explore the apparatus freely for a 24-hour acclimation period. Only fish that completed the pretraining phase were used in the subsequent experiments. Cognition Experiment 1: Assessment of Spatial Cognitive Ability Following pretraining, twelve individuals from each group (hatchery-reared and wild) were randomly selected to perform an egocentric spatial learning task. Experimental fish were fasted for 24 h prior to testing and then transferred individually into the testing apparatus. After a 30-min acclimation period in the start zone, the partition was lifted and each 20-min trial was video-recorded. From the recordings, the following parameters were quantified: (1) the initial turning direction during the first three trials, used to assess behavioral lateralization; (2) the latency to reach the interaction zone (fish failing to do so within 20 min were gently guided using a plastic rod); and (3) the daily success rate, calculated as the proportion of fish that successfully entered the interaction zone each day. During testing, if the fish selected the correct opening, the trial ended. If a fish initially chose the incorrect opening, the trial continued until it either exited through the correct opening or until the 20-minute time limit was reached. Upon the first successful entry, the correct opening was immediately closed, and the fish was confined to the interaction zone for a 5-min social interaction period with conspecifics, accompanied by a small food reward. Each fish completed one trial per day, with the same opening remaining designated as the correct choice throughout the 7-day learning phase. Experiment 2: Assessment of Cognitive Flexibility Upon completion of the egocentric task, all fish underwent a reversal learning test on the following day to evaluate cognitive flexibility. In this task, the previously correct door was reversed, i.e., the formerly incorrect opening now led to the interaction zone. Each fish was allowed to acclimate for 30 min in the start zone before the partition was lifted to initiate a 20-min video-recorded trial. The daily success rate (proportion of fish successfully entering the interaction zone) was used as the primary performance measure. Experiment 3: Assessment of Spatial Cognitive Strategies To investigate spatial cognitive strategy preferences, a visual landmark (a plastic aquatic plant) was placed at the entrance of the correct doorway in the testing apparatus. The remaining twelve individuals from each group (previously pretrained but not tested in Experiment 1) were subjected to this allocentric spatial learning task. The experimental procedures were identical to those of the egocentric task, and all trials were video recorded from above. For each fish, the latency to enter the interaction zone (s) was extracted from the recordings. This value was compared with corresponding latencies obtained during the egocentric task to determine the predominant spatial strategy (allocentric vs. egocentric) adopted during spatial learning. Total Brain and Spatial Cognition-Related Brain Regions After completion of all behavioral tests, fish were euthanized with an overdose of MS-222 (300 mg/L). Brains were carefully dissected at 4°C and fixed in 4% phosphate-buffered formaldehyde (PFA) for 48 h. Following fixation, each brain was photographed from dorsal, ventral, and lateral views using a stereomicroscope (SZ61, Olympus, Japan). The volume ( V ) of the whole brain, telencephalon, and cerebellum were quantified using ImageJ software based on the ellipsoid formula (Huber et al., 1997 ; Guo et al., 2022 ): where L is the maximum anterior–posterior length, W the mediolateral width, and H the dorsoventral height of the measured brain region. Neuron Density The determination of neuronal density (number of neurons per mm²) followed the method of Triki et al. ( 2020 ). The telencephalon and cerebellum were isolated and stored in phosphate-buffered saline (PBS) at 4°C until analysis. Each brain region was homogenized in isotonic saline, and cell nuclei were stained with DAPI (4’,6-diamidino-2-phenylindole). Fluorescent images were captured using a fluorescence microscope (Leica DMRA2; Leica Microsystems, Wetzlar, Germany), and DAPI-positive nuclei were quantified in ImageJ (Schneider et al., 2012 ) as a proxy for total cell number in each region. Data analysis All statistical analyses were conducted using SPSS Statistics 26.0 (IBM, USA). Differences in lateralization (on the first three turning choices recorded during the egocentric spatial task) between wild and hatchery fish were analyzed using a binomial Generalized Linear Mixed Model (GLMM) with logit link-function. The model specified the turning choice (right/left) as a binary response variable, Group as a fixed effect, and ID as a random intercept to control for repeated measurements from the same individual. We did not include the trial as a fixed effect in these analyses since results indicated no or little effect. Spatial learning performance was assessed by comparing success rates and latencies across groups in the egocentric task, whereas cognitive flexibility was analyzed based on post-reversal success rates in the reversal learning phase. The dominant cognitive strategy was inferred by comparing latencies between egocentric and allocentric task conditions. Data normality was tested with the Shapiro–Wilk test, and Levene’s test was used to verify homogeneity of variance. For normally distributed data, independent-sample t -tests were applied; otherwise, the Mann–Whitney U test was used. All results are presented as mean ± standard error (SE). Statistical significance was set at P < 0.05. RESULTS Behavioral lateralization The GLMM on lateralization revealed a significant effect of group on turning preference (β = -2.368, P = 0.021). Wild fish showed a significant bias towards right turns, whereas hatchery-reared fish exhibited no significant directional preference (Fig. 2 ). Spatial cognitive ability Wild fish exhibited significantly shorter latencies when navigating the maze compared to hatchery-reared fish (Mann–Whitney U test, P < 0.001; Fig. 3 A). In addition, wild individuals achieved a higher overall success rate in the egocentric spatial task (independent-samples t -test, P < 0.001; Fig. 3 B). Over the 7-day training period, daily success rates progressively increased in the wild group and remained consistently higher than those of hatchery-reared fish throughout all sessions (Fig. 3 C). Cognitive flexibility In the reversal learning test, where the correct door was reversed, wild fish achieved a significantly higher overall success rate than hatchery-reared fish (independent-samples t -test, P = 0.038; Fig. 4 A). This performance advantage persisted throughout the entire testing phase (Fig. 4 B). Spatial cognitive strategies Both groups relied more effectively on an egocentric (self turn-based) strategy than on an allocentric (landmark-based) one, as indicated by shorter completion times under egocentric conditions. Wild fish took significantly longer to complete the maze in the allocentric task than in the egocentric task (Mann–Whitney U test, P < 0.001; Fig. 5 A). Hatchery-reared fish also showed longer latencies under the allocentric condition, although the difference was not statistically significant (Mann–Whitney U test, P = 0.211; Fig. 5 B). Brain size Morphometric analysis revealed no detectable differences in relative volumes of telencephalon and cerebellum (telencephalon: independent-samples t-test, P = 0.20; cerebellum: Mann–Whitney U test, P = 0.69; Fig. 6 A, B). The neuronal density (DAPI-positive cells per gram of tissue) was slightly higher on average in wild fish in both brain regions, but again, the differences were not significant (telencephalon: independent-samples t -test, P = 0.39; cerebellum: Mann–Whitney U test, P = 0.485; Fig. 6 C, D). DISCUSSION Behavioral Lateralization In the present study, wild marbled rockfish exhibited a pronounced right-turning bias, whereas hatchery-reared conspecifics did not. This difference in lateralization, i.e., the consistent preference for using one side of their body or sensory organs during specific behaviors (Zhao & Li, 2016 ), could reflect differences in neural development and ecological experience. In natural habitats, where predation pressure and environmental complexity are high, lateralization can enhance performance in tasks requiring simultaneous vigilance and foraging. Behavioral lateralization is widespread across vertebrates and invertebrates (Rogers & Andrew, 2002 ) and is thought to improve cognitive efficiency by reducing decision-making time and enhancing environmental adaptability (Sovrano et al., 2018 ; Rogers, 2014 , 2021 ). In fishes with laterally positioned eyes, such asymmetry manifests as hemisphere specialization (Vallortigara and Rogers, 2005 ), possibly facilitating multitasking during foraging (Güntürkün, 2012 ) and learning (Bisazza and Dadda, 2005 ; Dadda and Bisazza, 2006 ). For example, in Brachyraphis episcopi , strongly lateralized individuals double their predation success compared with non-lateralized ones (Brown and Braithwaite, 2005 ). Conclusions on ecological effects of lateralization in marble rockfish are speculative at the current stage of research and future studies should explore the question in more detail. Spatial Cognitive Ability Wild marbled rockfish navigated mazes more rapidly and successfully than hatchery-reared individuals, indicating superior spatial learning and memory. These results reinforce the notion that environmental enrichment, through habitat complexity, sensory diversity, or social interactions, plays a pivotal role in developing cognitive competence (Rogers et al., 2004 ; Diniz et al., 2020 ). Previous work has demonstrated that structural enrichment stimulates neurogenesis and enhances spatial cognition in several species of hatchery-reared fish, e.g. Atlantic salmon ( Salmo salar ) (Salvanes et al., 2013 ), gibel carp ( Carassius gibelio ) (Abreu et al., 2019 ), and black rockfish ( Sebastes schlegelii ) (Zhang et al., 2021 ). Impoverished sensory- and structural environments in hatchery tanks may constrain neural development, leading to the cognitive deficits observed. Drawing from previous studies, addition of environmental enrichment could be one way to improve spatial learning abilities in the marbled rockfish. Spatial cognition enables animals to navigate, locate resources, and select suitable habitats—capabilities essential for survival and reproduction (Brown, 2003 ; Grieves and Jeffery, 2017 ). Impaired spatial cognition has been implicated in the reduced behavioral adaptability and post-release survival of hatchery-reared fish (Johnsson et al., 2014 ; Araki et al., 2008 ; Ebbesson and Braithwaite, 2012 ). Environmental conditions during development profoundly shape these abilities (Brockmark et al., 2012; Dalesman and Lukowiak, 2011 ). For example, three-spined sticklebacks from structurally complex rivers exhibit larger telencephalon volumes than conspecifics from homogeneous lakes (Ahmed et al., 2017 ), and angelfish ( Pterophyllum scalare ) reared in enriched environments show greater telencephalic neuron density and improved learning performance (Diniz et al., 2020 ). Spatial Cognitive Strategies Animals differ markedly in how they perceive and respond to spatial information, often employing distinct navigational strategies—egocentric (self-referenced) or allocentric (landmark-referenced), depending on environmental cue reliability and varying among species (Odling-Smee and Braithwaite, 2003a , b ; Sovrano et al., 2020 ; Yashina et al., 2019 ; Warburton, 1990 ; Brown et al., 2007 ). Thus, different spatial cognitive strategies could represent adaptive trade-offs shaped by environmental demands. Both hatchery-reared and wild marbled rockfish performed better under egocentric conditions than under landmark (allocentric) conditions, suggesting a general reliance on turn-based strategies. Artificial landmarks (e.g., plastic plants) may have elicited neophobic or avoidance responses, thus interfering with their function as spatial cues. Environmental stability also shapes navigational strategy: animals in dynamic habitats often favor egocentric strategies for rapid adaptation, whereas those in stable environments depend more on fixed landmark cues (Biegler and Morris, 1996 ). Wild marbled rockfish inhabit structurally complex, variable reef environments where egocentric navigation may be advantageous for rapid decision-making. In contrast, hatchery fish raised in homogenous tanks lack opportunities to form allocentric representations. Future studies incorporating graded enrichment and naturalistic spatial cues could clarify how environmental complexity modulates the ontogeny and flexibility of navigational strategies in reef fishes. Cognitive Flexibility Cognitive flexibility, capacity to modify learned behaviors when environmental contingencies change, is essential for adaptive decision-making and reversal learning tasks are widely used to quantify this ability (Prado et al., 2017 ; Benzina et al., 2021 ). Wild marbled rockfish exhibited higher reversal-learning success than hatchery-reared individuals, demonstrating greater flexibility in updating spatial learning strategies. Conversely, hatchery fish often persisted along incorrect routes, suggesting difficulty in behavioral inhibition and rule shifting. Such deficits likely result from the monotonous and predictable hatchery environment, which lacks the variable stimuli that foster behavioral adaptability. In contrast, wild fish experience constant environmental change, predation threats, and resource variability, all of which promote flexible learning (Sommer-Trembo et al., 2017 ). Similar habitat-related effects have been reported in sticklebacks, where individuals from fluctuating river habitats employ multiple spatial strategies, whereas pond-dwelling conspecifics rely on a single, fixed approach (Girvan and Braithwaite, 1998 ). Overall, environmental heterogeneity appears to stimulate experience-dependent plasticity in cognition. The superior flexibility observed in wild rockfish thus likely reflects adaptive neural tuning to environmental complexity, highlighting the need for environmental enrichment in hatchery protocols to mitigate cognitive deficiency. Brain Volume and Neuronal Density The brain is the central organ governing cognition, with the telencephalon mediating higher-order processing and the cerebellum coordinating balance and motor control. Several previous studies have reported reduced brain volumes in hatchery-reared fish compared with wild conspecifics, e.g. in rainbow trout ( Oncorhynchus mykiss ) and Chinook salmon ( O. tshawytscha ) (Marchetti and Nevitt, 2003 ; Kihslinger et al., 2006 ). Previous studies on brain-size selected guppies ( Poecilia reticulata ) also indicate that brain size can be associated with spatial cognition tasks (Kotrschal et al. 2015 ). In our study, however, wild and hatchery-reared marbled rockfish exhibited similar mean telencephalon and cerebellum volumes. Similarly, our histological analysis revealed no significant difference in neuronal density. However, subtle cellular-level variations such as total neuron number, soma size, or neuropil volume, undetectable using the current assessment protocol, may still underlie cognitive differences. We therefore do not reject the possibility that there may be an underlying neurological explanation to the observed cognitive differences. Future research employing advanced neuroimaging or molecular techniques could help elucidate such fine-scale neural correlates of cognition and the wild vs. hatchery-reared marbled rockfish system could be a suitable model system worthy of further investigation. CONCLUSION This study provides comprehensive evidence that captivity impairs spatial cognition, behavioral lateralization, and cognitive flexibility in marbled rockfish. Wild individuals displayed pronounced lateralization, faster and more accurate spatial navigation, and superior reversal-learning performance, consistent with enhanced adaptability to dynamic reef environments. These findings imply the critical role of habitat heterogeneity in shaping cognitive and neural development in fish and highlight the potential of environmental enrichment to improve behavioral competence and post-release survival in hatchery-reared reef species. Declarations Author contributions C.L.: writing – original draft, formal analysis, visualization, investigation. H.G.: writing – original draft, writing – review & editing, supervision, project administration, conceptualization, methodology, funding acquisition. Y.O.: investigation, visualization, validation, methodology, formal analysis, data curation. J.N.: writing – review & editing, visualization, formal analysis. Y.H.: investigation. C.Z.: investigation. X.Z.: conceptualization. All authors have read and agreed to the published version of the manuscript. Funding This study was supported by the Natural Science Foundation of National Natural Science Foundation of China (32573485 and 32102755), Natural Science Foundation of Zhejiang Province (LGN22C190015). References Abreu CC, Fernandes TN, Henrique EP, Pereira PDC, Marques SB, Herdeiro SLS, Oliveira FRR, Magalhães NGM, Anthony DC, Guerreiro-Diniz C, Melo MAD, Diniz DG, Picanco-Diniz CW (2019) Small-scale environmental enrichment and exercise enhance learning and spatial memory of Carassius auratus, and increase cell proliferation in the telencephalon: an exploratory study. Braz J Med Biol Res 52(5):e8026. https://doi.org/10.1590/1414-431X20198026 Adriaenssens B, Johnsson JI (2011) Learning and context-specific exploration behaviour in hatchery and wild brown trout. Appl Anim Behav Sci 132(1–2):90–99. https://doi.org/10.1016/j.applanim.2011.03.005 Ahmed NI, Thompson C, Bolnick DI, Stuart YE (2017) Brain morphology of the threespine stickleback ( Gasterosteus aculeatus ) varies inconsistently with respect to habitat complexity: a test of the Clever Foraging Hypothesis. Ecol Evol 7(10). https://doi.org/10.1002/ece3.2918 Bisazza A, Dadda M (2005) Enhanced schooling performance in lateralized fishes. Proceedings of the Royal Society B 272(1573): 1677–1681. https://doi.org/10.1098/rspb.2005.3145 Araki H, Berejikian BA, Ford MJ, Blouin MS (2008) Fitness of hatchery-reared salmonids in the wild. Evol Appl 1:342–355. https://doi.org/10.1111/j.1752-4571.2008.00026.x Barmack NH (2003) Central vestibular system: vestibular nuclei and posterior cerebellum. Brain Res Bull 60(5–6):511–541. https://doi.org/10.1016/S0361-9230(03)00055-8 Benzina N, N’Diaye K, Pelissolo A, Mallet L, Burguière E (2021) A cross-species assessment of behavioral flexibility in compulsive disorders. Commun Biology 4(1):96. https://doi.org/10.1038/s42003-020-01611-y Brockmark S, Adriaenssens B, Johnsson I (2010) Less is more: density influences the development of behavioural life skills in trout. Proceedings of the Royal Society B 277(1696): 3035–3043 Brown AA, Spetch ML, Hurd PL (2007) Growing in circles: rearing environment alters spatial navigation in fish. Psychol Sci 18(7):569–573. https://doi.org/10.1098/rspb.2010.0561 Brown AD, Sisneros JA, Jurasin T, Nguyen C, Coffin AB (2013) Differences in lateral line morphology between hatchery-and wild-origin steelhead. PLoS ONE 8(3):e59162. https://doi.org/10.1371/journal.pone.0059162 Brown C (2003) Habitat-predator association and avoidance in rainbowfish ( Melanotaenia spp. Ecol Freshw Fish 12(2):118–126. https://doi.org/10.1034/j.1600-0633.2003.00007.x Brown C, Braithwaite VA (2005) Effects of predation pressure on the cognitive ability of the poeciliid Brachyraphis episcopi . Behav Ecol 16(2):482–487. https://doi.org/10.1093/beheco/ari016 Biegler R, Morris RG (1996) Landmark stability: studies exploring whether the perceived stability of the environment influences spatial representation. J Exp Biol 199(1):187–193. https://doi.org/10.1242/jeb.199.1.187 Chen L, Wang HX, Xu KD, Lv ZY, Huang B, Li Z, Liang J, Zhou YD, Li PF, Liu LW (2022) Analysis of current situation of proliferation and release of island and reef fishes in the coastal waters of Zhejiang. J Zhejiang Ocean University(Natural Science) 41(05):459–465 Dadda M, Bisazza A (2006) Does brain asymmetry allow efficient performance of simultaneous tasks? Animal Behaviour. 72(3):523–529. https://doi.org/10.1016/j.anbehav.2005.10.019 Dalesman S, Lukowiak K (2011) Social snails: the effect of social isolation on cognition is dependent on environmental context. J Exp Biol 214(24):4179–4185. https://doi.org/10.1242/jeb.064857 Diniz DG, de Siqueira LS, Henrique EP, Pereira PDC, Diniz CG, de Abreu CC, de Morais Magalhães NG, da Silva Soares GL, Guimarães Paixão PE, Meneses JL, do Couto MVS, da, Costa Sousa S, dos Santos Cunha F, Picanço Diniz CW, Fujimoto RY (2020) Environmental enrichment increases the number of telencephalic but not tectal cells of angelfish ( Pterophyllum scalare ): an exploratory investigation using optical fractionator. Environmental Biology of Fishes 103: 847–857 Dunlap KD (2016) Fish neurogenesis in context: assessing environmental influences on brain plasticity within a highly labile physiology and morphology. Brain Behav Evol 87(3):156–166. https://doi.org/10.1159/000446907 Ebbesson L, Braithwaite VA (2012) Environmental effects on fish neural plasticity and cognition. J Fish Biol 81(7):2151–2174. https://doi.org/10.1111/j.1095-8649.2012.03486.x Ge S, Sailor KA, Ming G, Song H (2008) Synaptic integration and plasticity of new neurons in the adult hippocampus. J Physiol 586(16):3759–3765. https://doi.org/10.1113/jphysiol.2008.155655 Girvan JR, Braithwaite VA (1998) Population differences in spatial learning in three-spined sticklebacks. Proceedings of the Royal Society of London B 265(1399): 913–918. https://doi.org/10.1098/rspb.1998.0378 Grieves RM, Jeffery KJ (2017) The representation of space in the brain. Behavioural Processes 135: 113–131. https://doi.org/10.1016/j.beproc.2016.12.012 Güntürkün O (2012) The convergent evolution of neural substrates for cognition. Psychol Res 76(2):212–219 Guo HY, Näslund J, Thomassen RT, Larsen MH (2022) Social isolation affects intra-specific interaction behaviour and reduces the size of the cerebellar brain region in juvenile Atlantic salmon Salmo salar . J Fish Biol 101(3):711–721. https://doi.org/10.1111/jfb.15142 Guo HY, Zhang XF, Näslund J, Peng LY, Liu CH, Tian MJ, Chai XJ, Zhang DY, Zhang XM (2022) Differences in external morphology, body composition and swimming performance between hatchery-and wild-origin marbled rockfish ( Sebastiscus marmoratus ). Front Mar Sci 9:912129. https://doi.org/10.3389/fmars.2022.912129 Huber R, van Staaden MJ, Kaufan LS, Liem KF (1997) Microhabitat use, trophic patterns, and the evolution of brain structure in African cichlids. Brain, Behavior and Evolution 50,(3), 167–182 Johnsson JI, Brockmark S, Näslund J (2014) Environmental effects on behavioural development consequences for fitness of captive-reared fishes in the wild. J Fish Biol 85(6):1946–1971. https://doi.org/10.1111/jfb.12547 Kihslinger RL, Nevitt GA (2006) Early rearing environment impacts cerebellar growth in juvenile salmon. Journal of Experimental Biology, 2006, 209(3): 504–509. https://doi.org/10.1242/jeb.02019 Kihslinger RL, Lema SC, Nevitt GA (2006) Environmental rearing conditions produce forebrain differences in wild Chinook salmon Oncorhynchus tshawytscha . Comp Biochem Physiol A: Mol Integr Physiol 145(2):145–151. https://doi.org/10.1016/j.cbpa.2006.06.041 Kotrschal A, Corral-Lopez A, Amcoff M, Kolm N (2015) A larger brain confers a benefit in a spatial mate search learning task in male guppies. Behav Ecol 26(2):527–532. https://doi.org/10.1093/beheco/aru227 Lorenzen K, Beveridge MC, Mangel M (2012) Cultured fish: integrative biology and management of domestication and interactions with wild fish. Biol Rev 87(3):639–660. https://doi.org/10.1111/j.1469-185X.2011.00215.x Lucon-Xiccato T, Bisazza A (2017) Sex differences in spatial abilities and cognitive flexibility in the guppy. Anim Behav 123:53–60. https://doi.org/10.1016/j.anbehav.2016.10.026 Makino H, Masuda R, Tanaka M (2015) Environmental stimuli improve learning capability in striped knifejaw juveniles: the stage-specific effect of environmental enrichment and the comparison between wild and hatchery-reared fish. Fish Sci 81:1035–1042 Marchetti MP, Nevitt GA (2003) Effects of hatchery rearing on brain structures of rainbow trout, Oncorhynchus mykiss . Environ Biol Fish 66:9–14 Mazzei R, Lampe M, Ohnesorge A, Pajot A, Soares MC, Bshary R (2019) Ecological differences in the facultative Caribbean cleaning goby Elacatinus prochilos do not predict learning performance in discriminatory two-choice tasks. Anim Cogn 22(6):1039–1050. https://doi.org/10.1007/s10071-019-01295-w Näslund J (2021) Reared to become wild-like: addressing behavioral and cognitive deficits in cultured aquatic animals destined for stocking into natural environments-a critical review. Bull Mar Sci 97(4):489–538. https://doi.org/10.5343/bms.2020.0039 Odling-Smee L, Braithwaite VA (2003a) The role of learning in fish orientation. Fish Fish 4(3):235–246. https://doi.org/10.1046/j.1467-2979.2003.00127.x Odling-Smee L, Braithwaite VA (2003b) The influence of habitat stability on landmark use during spatial learning in the three-spined stickleback. Anim Behav 65(4):701–707. https://doi.org/10.1006/anbe.2003.2082 Pillans RD, Bearham D, Boomer A, Downie R, Patterson TA, Thomson DP, Babcock R (2014) Multi year observations reveal variability in residence of a tropical demersal fish, Lethrinus nebulosus : implications for spatial management. PLoS One, 2014, 9(9): e105507. https://doi.org/10.1371/journal.pone.0105507 Poucet B (1993) Spatial cognitive maps in animals: new hypotheses on their structure and neural mechanisms. Psychol Rev 100(2):163–182. https://doi.org/10.1037/0033-295X.100.2.163 Prado VF, Janickova H, Al-Onaizi MA, Prado MA (2017) Cholinergic circuits in cognitive flexibility. Neuroscience 345:130–141. https://doi.org/10.1016/j.neuroscience.2016.09.013 Qi YL, Liu CH, Yuan GZ, Guo HY, Näslund J, Wang YC, Ru JF, Ou YY, Chai XJ, Zhang XM (2024) Disparities in body color adaptability and ambient light color preference between wild and hatchery-reared marbled rockfish ( Sebastiscus marmoratus ). Animals 14(11):1701. https://doi.org/10.3390/ani14111701 Rogers LJ (2014) Asymmetry of brain and behavior in animals: Its development, function, and human relevance. genesis 52(6): 555–571. https://doi.org/10.1002/dvg.22741 Rogers LJ (2021) Brain lateralization and cognitive capacity. Animals 11(7): 1996. https://doi.org/10.3390/ani11071996 Rogers LJ, Andrew R (2002) Comparative vertebrate lateralization. Cambridge University Press, 2002 Rogers LJ, Zucca P, Vallortigara G (2004) Advantages of having a lateralized brain. Proceedings of the Royal Society of London B, 2004, 271(suppl_6): S420-S422. https://doi.org/10.1098/rsbl.2004.0200 Salvanes AGV, Moberg O, Ebbesson LO, Nilsen TO, Jensen KH, Braithwaite VA (2013) Environmental enrichment promotes neural plasticity and cognitive ability in fish. Proceedings of the Royal Society B 280(1767): 20131331. https://doi.org/10.1098/rspb.2013.1331 Schneider CA, Rasband WS, Eliceiri KW (2012) NIH image to ImageJ: 25 years of image analysis. Nature Methods, 2012, 9, 671–675 Sheenaja KK, Thomas KJ (2011) Influence of habitat complexity on route learning among different populations of climbing perch ( Anabas testudineus Bloch, 1792). Mar Freshw Behav Physiol 44:349–358. https://doi.org/10.1080/10236244.2011.642503 Sommer-Trembo C, Petry AC, Silva GG, Vurusic SM, Gismann J, Baier J, Krause S, de Araujo Cardoso Iorio J, Riesch R, Plath M (2017) Predation risk and abiotic habitat parameters affect personality traits in extremophile populations of a neotropical fish ( Poecilia vivipara ). Ecol Evol 7(16):6570–6581. https://doi.org/10.1002/ece3.3165 Sovrano VA, Baratti G, Lee SA (2020) The role of learning and environmental geometry in landmark-based spatial reorientation of fish ( Xenotoca eiseni ). PLoS ONE 15(3):e229608. https://doi.org/10.1371/journal.pone.0229608 Sovrano VA, Baratti G, Potrich D (2018) A detour task in four species of fishes. Front Psychol 9:2341. https://doi.org/10.3389/fpsyg.2018.02341 Sundström LF, Johnsson JI (2001) Experience and social environment influence the ability of young brown trout to forage on live novel prey. Anim Behav 61(1):249–255. https://doi.org/10.1006/anbe.2000.1593 Triki Z, Emery Y, Teles MC, Oliveira RF, Bshary R (2020) Brain morphology predicts social intelligence in wild cleaner fish. Nat Commun 11(1):6423. https://doi.org/10.1038/s41467-020-20130-2 Valente AE, Huang K, Portugues R, Engert F (2012) Ontogeny of classical and operant learning behaviors in zebrafish. Learn Mem 19(4):170–177. http://www.learnmem.org/cgi/doi/ 10.1101/lm.025668.112 Vallortigara G, Rogers L (2005) Survival with an asymmetrical brain: advantages and disadvantages of cerebral lateralization. Behav Brain Sci 28(4):575–588. https://doi.org/10.1017/S0140525X0528010X Wang ZH, Zhong JM, Zhang SY, Wang K, Lin J, Zhang J, Shen H (2019) Habitat use of juvenile rockfish ( Sebastiscus marmoratus ) in mussel farming waters: a preliminary study. J Fisheries China 43(09):1900–1913 Warburton K (1990) The use of local landmarks by foraging goldfish. Anim Behav 40(3):500–505. https://doi.org/10.1016/S0003-3472(05)80530-5 Wu CW (1999) Biological Studies on Sebastiscus marmoratus off Zhoushan. J Zhejiang Ocean Univ (Natural Science) (03): 185–190 Yashina K, Tejero-Cantero L, Herz A, Baier H (2019) Zebrafish exploit visual cues and geometric relationships to form a spatial memory. iScience 19(C):119–134 Zhang ZH, Fu YQ, Shen FY, Zhang Z, Guo HY, Zhang XM (2021) Barren environment damages cognitive abilities in fish: Behavioral and transcriptome mechanisms. Sci Total Environ 794:148805. https://doi.org/10.1016/j.scitotenv.2021.148805 Zhao DP, Li BG (2016) Current research status on behavioral laterality in Chinese nonhuman primates. Acta Theriol Sinica 036(002):232–240. https://doi.org/10.16829/j.slxb.201602012 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviewers agreed at journal 24 Apr, 2026 Reviews received at journal 16 Apr, 2026 Reviewers agreed at journal 12 Mar, 2026 Reviewers agreed at journal 04 Mar, 2026 Reviewers invited by journal 27 Jan, 2026 Editor assigned by journal 23 Dec, 2025 Submission checks completed at journal 23 Dec, 2025 First submitted to journal 22 Dec, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8422304","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":581355009,"identity":"694e0e74-2f67-4eb8-8b0c-77e42ef70fbf","order_by":0,"name":"Chenhang Lv","email":"","orcid":"","institution":"Zhejiang Ocean University","correspondingAuthor":false,"prefix":"","firstName":"Chenhang","middleName":"","lastName":"Lv","suffix":""},{"id":581355012,"identity":"b9e08ce1-d239-4e00-97be-e190a7338eb5","order_by":1,"name":"Haoyu Guo","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAvUlEQVRIiWNgGAWjYBACAxiDn5n58APStEi2s6UZ4FOJqcXgPI+CBFFazNkPH5Pm+XVYzvgwD1B/jU00QS2WPWlp0rx9h43NDvMeeMBwLC23gaDDDuSYSfP2HE7cdpgvwYCx4TARWs6/gWjZ3MxjIEGclhtAW3h+HE7cwEy8lmfJlnMb0o0lDgMDOYEov5xPPnjjzR9rOf7+w4cffKixIawFCFgkGNugzAQilIMA8weGP0QqHQWjYBSMgpEJANZ5P1XbEdhZAAAAAElFTkSuQmCC","orcid":"","institution":"Zhejiang Ocean University","correspondingAuthor":true,"prefix":"","firstName":"Haoyu","middleName":"","lastName":"Guo","suffix":""},{"id":581355014,"identity":"13cc079b-49e8-444f-b4a1-ca68c62871ef","order_by":2,"name":"Yingying Ou","email":"","orcid":"","institution":"Zhejiang Ocean University","correspondingAuthor":false,"prefix":"","firstName":"Yingying","middleName":"","lastName":"Ou","suffix":""},{"id":581355016,"identity":"1e5c73b9-960a-49c0-9be9-148f85dca75b","order_by":3,"name":"Joacim Näslund","email":"","orcid":"","institution":"Institute of Freshwater Research, Swedish University of Agricultural Sciences","correspondingAuthor":false,"prefix":"","firstName":"Joacim","middleName":"","lastName":"Näslund","suffix":""},{"id":581355017,"identity":"d3db691f-8e98-4858-a73a-e5f7ace65995","order_by":4,"name":"Yuling Hong","email":"","orcid":"","institution":"Zhejiang Ocean University","correspondingAuthor":false,"prefix":"","firstName":"Yuling","middleName":"","lastName":"Hong","suffix":""},{"id":581355020,"identity":"06bc762d-de09-4b6d-bc37-67aa846d5356","order_by":5,"name":"Chaojun Zhu","email":"","orcid":"","institution":"Zhejiang Ocean University","correspondingAuthor":false,"prefix":"","firstName":"Chaojun","middleName":"","lastName":"Zhu","suffix":""},{"id":581355023,"identity":"b75fe38d-82a1-4dcd-9b3f-0da1529b6772","order_by":6,"name":"Xiumei Zhang","email":"","orcid":"","institution":"Zhejiang Ocean University","correspondingAuthor":false,"prefix":"","firstName":"Xiumei","middleName":"","lastName":"Zhang","suffix":""}],"badges":[],"createdAt":"2025-12-22 07:53:06","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8422304/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8422304/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":101447253,"identity":"ba0fb7a2-182d-4b34-bf16-cf5f24a902e3","added_by":"auto","created_at":"2026-01-29 18:52:00","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":111891,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic diagram of the double-door maze used for spatial cognition tests. (A) Start zone, (B) choice zone, (C) landmark (plastic plant), (D) false door (blocked by a transparent acrylic board), (E) conspecifics interaction zone, (F) attraction zone (with conspecifics inside and red light).\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8422304/v1/3e3a4ff42c4e18b1001cea04.png"},{"id":101751400,"identity":"7e6918dd-d170-4c0e-8905-a80349549bba","added_by":"auto","created_at":"2026-02-03 10:20:01","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":45873,"visible":true,"origin":"","legend":"\u003cp\u003eBehavioral lateralization in hatchery-reared and wild marbled rockfish. Bars represent the proportion of right-turn choices made by each group during the first three trials of egocentric spatial task (binomial test，hatchery-reared: \u003cem\u003eP\u003c/em\u003e = 0.248, n = 12; wild: \u003cem\u003eP\u003c/em\u003e \u0026lt; 0.001, n = 12).\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-8422304/v1/692f2a23d94a4e1c8bebae2d.png"},{"id":101447254,"identity":"f2939530-129f-48a6-b611-67d9a1995b7d","added_by":"auto","created_at":"2026-01-29 18:52:00","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":77873,"visible":true,"origin":"","legend":"\u003cp\u003eComparative analysis of spatial cognitive abilities in the egocentric spatial task between hatchery-reared and wild marbled rockfish. (A) Mean latency to reach the goal zone (Mann-Whitney \u003cem\u003eU\u003c/em\u003e test; hatchery-reared: \u003cem\u003en\u003c/em\u003e = 12, wild: \u003cem\u003en\u003c/em\u003e= 12). (B) Mean success rate across trials (independent samples \u003cem\u003et\u003c/em\u003e-test; hatchery-reared: \u003cem\u003en\u003c/em\u003e = 12, wild: \u003cem\u003en\u003c/em\u003e = 12). (C) Daily success rates over the 7-day testing period.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-8422304/v1/b81365b7df567aa059cece4e.png"},{"id":101447256,"identity":"661be42e-20fc-4681-a234-7a8d024497b0","added_by":"auto","created_at":"2026-01-29 18:52:00","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":49405,"visible":true,"origin":"","legend":"\u003cp\u003eCognitive flexibility test in hatchery-reared and wild marbled rockfish. (A) Mean success rate following rule reversal (independent samples \u003cem\u003et\u003c/em\u003e-test; hatchery-reared: n = 12, wild: n = 12). (B) Daily success rates during the 7-day reversal learning phase.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-8422304/v1/c722290aa4be9e92e4ff9a96.png"},{"id":101751364,"identity":"94591efb-5ed4-46bc-a765-47071c717718","added_by":"auto","created_at":"2026-02-03 10:19:46","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":59483,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of maze completion times using egocentric or allocentric spatial strategies in hatchery-reared and wild marbled rockfish. (A) Wild fish. (B) Hatchery-reared fish (Mann-Whitney U test; hatchery-reared: n = 12, wild: n = 12).\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-8422304/v1/cf4e91154db4f1948cadf155.png"},{"id":101447258,"identity":"838e8af0-1c76-4394-b7e5-5d617e57e0c6","added_by":"auto","created_at":"2026-01-29 18:52:00","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":70381,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of the brain morphology and neuronal density between hatchery-reared and wild marbled rockfish. (A) Telencephalon-to-total brain volume ratio (independent samples t-test; hatchery-reared: n = 5, wild: n = 5). (B) Cerebellum-to-total brain volume ratio (Mann-Whitney U test; hatchery-reared: n = 5, wild: n = 5). (C) Neuronal density of telencephalic tissue (independent samples t-test; hatchery-reared: n = 6, wild: n = 6). (D) Neuronal density of cerebellar tissue (Mann-Whitney U test; hatchery-reared: n = 6, wild: n = 6).\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-8422304/v1/6ac29aa0247ea24ccee8d3f5.png"},{"id":102403991,"identity":"8dc53999-816f-4674-b874-fd89f92b9e0f","added_by":"auto","created_at":"2026-02-11 10:51:58","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1053688,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8422304/v1/8074dfa1-bd48-4950-969a-f4911c5541bf.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Cognitive costs of captivity: hatchery-reared marbled rockfish have impaired spatial cognition","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eMany studies have demonstrated significant behavioral divergences between hatchery-reared fish and their wild conspecifics, with well-documented differences in predator avoidance, social interactions, prey recognition, capture efficiency, and territoriality (Lorenzen et al., \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). For instance, hatchery-reared brown trout (\u003cem\u003eSalmo trutta\u003c/em\u003e) display less consistent exploratory strategies in novel environments and require more time to acquire novel prey-capture skills than wild trout (Sundstr\u0026ouml;m and Johnsson, \u003cspan citationid=\"CR53\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Adriaenssens and Johnsson, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). Such behavioral deviations may reduce environmental adaptability and contribute to low post-release survival (Johnsson et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2014\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSpatial cognition (i.e. the acquisition, organization, and application of spatial information to navigate and interpret environmental structure) involves learning, memory, and the use of three-dimensional environmental cues for navigation (Poucet, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e1993\u003c/span\u003e). Substantial inter- and intraspecific variation has been documented across fish taxa. For example, male guppies (\u003cem\u003ePoecilia reticulata\u003c/em\u003e) outperform females in spatial learning tasks (Lucon-Xiccato and Bisazza, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2017\u003c/span\u003e), zebrafish (\u003cem\u003eDanio rerio\u003c/em\u003e) show stage-dependent cognitive performance during development (Valente et al., \u003cspan citationid=\"CR55\" class=\"CitationRef\"\u003e2012\u003c/span\u003e), and multiple species differ in detour task performance (Sovrano et al., \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). These findings establish sex, age, and species identity as important determinants of spatial cognition.\u003c/p\u003e \u003cp\u003eBeyond intrinsic factors, environmental factors are also identified as important for spatial cognition. In climbing perch (\u003cem\u003eAnabas testudineus\u003c/em\u003e) maze trials, pond-dwelling individuals rely more on landmark cues, while river-dwelling individuals favor egocentric strategies (Sheenaja and Thomas, \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). Ecotype differences in broadstripe gobies (\u003cem\u003eElacatinus prochilos)\u003c/em\u003e also influence spatial learning (Mazzei et al., \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). In captive environments, environmental enrichment has, in some cases, been shown to promote brain size development, suggesting that the simplified, stimulus-poor conditions of aquaculture may inhibit neural and cognitive development (N\u0026auml;slund, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn rocky reef habitats, a well-developed spatial cognitive ability is likely a key adaptation enabling reef-dwelling species to thrive in the complex environment. Consequently, deficits in spatial abilities may help explain the poor post-release survival of hatchery-reared reef species. The marbled rockfish (\u003cem\u003eSebastiscus marmoratus\u003c/em\u003e) is an economically important species with a distribution in the coastal areas of China, Japan and Korea. It is a typical reef-dwelling species, widely distributed in nearshore rocky reef areas and is among the most popular recreational fish targets in Eastern Asia (Sun et al., 2024; Wu, \u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e1999\u003c/span\u003e; Wang et al., \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). From 2018 to 2021, approximately 500,000 marbled rockfish were released into coastal waters of the Zhejiang Province (Chen et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). However, previous studies indicate that hatchery-reared reef fish, including marbled rockfish, differ significantly from wild conspecifics in key traits, potentially compromising their post-release survival (Guo et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Qi et al., \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e2024\u003c/span\u003e). Despite recognition of spatial cognition as a vital survival trait for reef-dwelling fish (Pillans et al., \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2014\u003c/span\u003e), differences between hatchery-reared and wild individuals, as well as the neural mechanisms underlying such variation, remain poorly understood.\u003c/p\u003e \u003cp\u003eHere, we aimed to systematically compare spatial cognition, strategy use, lateralization, and cognitive flexibility between hatchery-reared and wild marbled rockfish using a maze setup, and we preliminarily examined the neurobiological basis underlying these differences. A general hypothesis of hatchery environment impairing cognition was used, with matching predictions of lower test performance in hatchery-reared individuals compared with wild conspecifics.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003eExperimental Animals and Holding Conditions\u003c/h2\u003e\n \u003cp\u003eAll hatchery-reared marbled rockfish used in this study were the progeny of wild-caught fish captured from the waters near Dongji Island, Zhoushan, China (30\u0026deg;12\u0026prime;N, 122\u0026deg;40\u0026prime;E). The hatchery-reared population used for this study was produced in January 2020 and then reared in nursery ponds (size: 5 m \u0026times; 6 m \u0026times; 1 m) in a commercial hatchery (Xixuan Technology Island) in Zhoushan, according to the standard methodology for the intensive culture of this species. The nursery ponds received a continuous flow of sand-filtered natural seawater (flow rate: 2 m\u0026sup3;/h), gently aerated by air-stone diffusers. Water temperature was maintained between 23 and 25\u0026deg;C, with stocking densities ranging from 5,000 to 10,000 individuals per cubic meter. During the hatchery phase, fish were fed a commercial pellet diet (Hayashikane Sangyo, Co., Ltd., Yamaguchi Prefecture, Japan; composition: crude protein\u0026thinsp;\u0026ge;\u0026thinsp;50.0%, lipid\u0026thinsp;\u0026ge;\u0026thinsp;6.0%, fiber\u0026thinsp;\u0026le;\u0026thinsp;3.0%, and ash\u0026thinsp;\u0026le;\u0026thinsp;17.0%).\u003c/p\u003e\n \u003cp\u003eIn early December 2022, 30 hatchery-reared individuals of near-uniform size (total length: 8.02\u0026thinsp;\u0026plusmn;\u0026thinsp;0.91 cm, mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD) were selected and transferred to the Laboratory of Marine Ranching Stock Enhancement (LMRSE), Zhejiang University. They were acclimated in circular tanks (water volume: 1,780 L; inner diameter: 1.6 m; height: 0.8 m) equipped with a recirculating seawater system. During acclimation, water temperature was maintained constant at 17\u0026deg;C, consistent with the concurrent ambient sea temperature (water quality parameters: dissolved oxygen\u0026thinsp;\u0026ge;\u0026thinsp;6.0 mg/L, unionized ammonia\u0026thinsp;\u0026lt;\u0026thinsp;0.05 mg/L, salinity\u0026thinsp;=\u0026thinsp;28\u0026permil;, pH ranging 8.0\u0026ndash;8.3). A photoperiod of 11 h light:13 h dark was implemented. Starting on the third day post-transport, fish were fed twice daily (at 09:00 and 18:00) to apparent satiation with commercial dry pellets (as above). Uneaten food and waste were removed by siphoning one hour after feeding.\u003c/p\u003e\n \u003cp\u003eWild marbled rockfish were captured by angling in December 2023, in the waters surrounding Dongji Island (30\u0026deg;43\u0026prime; N, 122\u0026deg;46\u0026prime; E). Thereby, the hatchery-reared and wild-caught fish likely belong to the same genetic stocks. Thirty wild marbled rockfish of uniform size (total body length: 8.19\u0026thinsp;\u0026plusmn;\u0026thinsp;0.97 cm, mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD) were selected and transported to a circular holding tank (water volume: 1780 L; inside diameter: 1.60 m; height: 0.80 m) equipped with a seawater circulation system at the Marine Ranching and Fishery Carbon Sink Ecological Function Innovation Laboratory (MRFCSEFIL) of Zhejiang Ocean University. The dimensions and water conditions of the holding tank for wild fish were identical to those of the tank for hatchery-reared fish, as both tanks were part of the same recirculating seawater system. To mimic natural conditions, shelter structures (plastic tubes) were introduced into the holding tank as environmental enrichment. Beginning on the third day after transport, the wild fish were fed live ridgetail white prawns (\u003cem\u003eExopalaemon carinicauda\u003c/em\u003e) every other day to ensure a constant supply of live prey in the tank.\u003c/p\u003e\n \u003cp\u003eThe Institutional Animal Care and Use Committee at Zhejiang Ocean University approved all animal housing and experimental procedures (No. 2022016). During the experiment, all fish were treated according to the Guide for the Care and Use of Laboratory Animals.\u003c/p\u003e\n\u003c/div\u003e\n\u003ch3\u003eApparatus\u003c/h3\u003e\n\u003cp\u003eA double-door maze apparatus was designed and constructed based on protocols established by Girvan \u0026amp; Braithwaite (\u003cspan class=\"CitationRef\"\u003e1998\u003c/span\u003e) and Makino et al. (\u003cspan class=\"CitationRef\"\u003e2015\u003c/span\u003e). The apparatus consisted of a rectangular glass tank (67 cm long \u0026times; 37 cm wide), internally divided into a start zone, a choice zone, an interaction zone, and an attraction zone (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). All trials were filmed from above using a high-definition camera (Hikvision; Hangzhou, Zhejiang, China). A removable transparent partition separated the start zone from the choice zone. An opaque acrylic partition was placed between the choice zone and the attraction zone. This partition featured two openings, each of which could be opened or closed independently. During the experiments, one opening remained open, serving as the sole correct exit (the goal), while the other was closed (blocked by a transparent acrylic board). A small opaque acrylic divider was positioned between the two openings. A transparent acrylic panel was installed between the attraction zone and the interaction zone to prevent fish in the attraction zone from leaving. The attraction zone contained five marbled rockfish, which served as a social attraction (preliminary experiments had confirmed the effectiveness of this conspecific grouping as an attractant). To further enhance the attraction effect, red light was provided above the attraction and interaction zones via a red filter. This approach was based on preliminary experiments that verified strong positive phototaxis to red light in the study species (also see Qi et al. \u003cspan class=\"CitationRef\"\u003e2024\u003c/span\u003e).\u003c/p\u003e\n\u003ch3\u003eExperimental Pretraining Protocol\u003c/h3\u003e\n\u003cp\u003eFollowing a 7-day acclimation period in the holding tanks, 24 fish were randomly selected from each of the hatchery-reared and wild groups for pre-training. The selected fish from each group were introduced into each of the two identical experimental apparatuses to familiarize them with the internal structures, with six fish being assigned to each apparatus. During this pre-training phase, the start zone was fully accessible, and both openings in the acrylic partition between the choice zone and the interaction zone were left open. The fish were allowed to explore the apparatus freely for a 24-hour acclimation period. Only fish that completed the pretraining phase were used in the subsequent experiments.\u003c/p\u003e\n\u003ch3\u003eCognition\u003c/h3\u003e\n\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\n \u003ch2\u003eExperiment 1: Assessment of Spatial Cognitive Ability\u003c/h2\u003e\n \u003cp\u003eFollowing pretraining, twelve individuals from each group (hatchery-reared and wild) were randomly selected to perform an egocentric spatial learning task. Experimental fish were fasted for 24 h prior to testing and then transferred individually into the testing apparatus. After a 30-min acclimation period in the start zone, the partition was lifted and each 20-min trial was video-recorded. From the recordings, the following parameters were quantified: (1) the initial turning direction during the first three trials, used to assess behavioral lateralization; (2) the latency to reach the interaction zone (fish failing to do so within 20 min were gently guided using a plastic rod); and (3) the daily success rate, calculated as the proportion of fish that successfully entered the interaction zone each day. During testing, if the fish selected the correct opening, the trial ended. If a fish initially chose the incorrect opening, the trial continued until it either exited through the correct opening or until the 20-minute time limit was reached.\u003c/p\u003e\n \u003cp\u003eUpon the first successful entry, the correct opening was immediately closed, and the fish was confined to the interaction zone for a 5-min social interaction period with conspecifics, accompanied by a small food reward. Each fish completed one trial per day, with the same opening remaining designated as the correct choice throughout the 7-day learning phase.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\n \u003ch2\u003eExperiment 2: Assessment of Cognitive Flexibility\u003c/h2\u003e\n \u003cp\u003eUpon completion of the egocentric task, all fish underwent a reversal learning test on the following day to evaluate cognitive flexibility. In this task, the previously correct door was reversed, i.e., the formerly incorrect opening now led to the interaction zone. Each fish was allowed to acclimate for 30 min in the start zone before the partition was lifted to initiate a 20-min video-recorded trial. The daily success rate (proportion of fish successfully entering the interaction zone) was used as the primary performance measure.\u003c/p\u003e\n\u003c/div\u003e\n\u003ch3\u003eExperiment 3: Assessment of Spatial Cognitive Strategies\u003c/h3\u003e\n\u003cp\u003eTo investigate spatial cognitive strategy preferences, a visual landmark (a plastic aquatic plant) was placed at the entrance of the correct doorway in the testing apparatus. The remaining twelve individuals from each group (previously pretrained but not tested in Experiment 1) were subjected to this allocentric spatial learning task. The experimental procedures were identical to those of the egocentric task, and all trials were video recorded from above.\u003c/p\u003e\n\u003cp\u003eFor each fish, the latency to enter the interaction zone (s) was extracted from the recordings. This value was compared with corresponding latencies obtained during the egocentric task to determine the predominant spatial strategy (allocentric vs. egocentric) adopted during spatial learning.\u003c/p\u003e\n\u003ch3\u003eTotal Brain and Spatial Cognition-Related Brain Regions\u003c/h3\u003e\n\u003cp\u003eAfter completion of all behavioral tests, fish were euthanized with an overdose of MS-222 (300 mg/L). Brains were carefully dissected at 4\u0026deg;C and fixed in 4% phosphate-buffered formaldehyde (PFA) for 48 h. Following fixation, each brain was photographed from dorsal, ventral, and lateral views using a stereomicroscope (SZ61, Olympus, Japan). The volume (\u003cem\u003eV\u003c/em\u003e) of the whole brain, telencephalon, and cerebellum were quantified using ImageJ software based on the ellipsoid formula (Huber et al., \u003cspan class=\"CitationRef\"\u003e1997\u003c/span\u003e; Guo et al., \u003cspan class=\"CitationRef\"\u003e2022\u003c/span\u003e):\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAKYAAAA8CAYAAADsdcFSAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAAFiUAABYlAUlSJPAAAAccSURBVHhe7ZzBaxNPFMe//f0BSqwnbaV00osIuQQFkYAeOsVrFa2nnCqbmx5UosVLLhuKxxhvOZkIghdTGg8KTS4pCvYgXpJFRDx1Df0L9ncws+y+7G52Y1I2zfvAQPPeZHey/e57b2Y2mbMsywLDxIz/qIFh4gALk4klLEwmlrAwmVjCwmRiCQuTiSUsTCaWsDCZWMLCZGLJiRHmzs4OdnZ2qJkZA69evUKr1aLmyWKdAPL5vFWtVqnZklJaAFxN0zTabSJ0u92Bc0spPcckpbSsv1vDrtbtdulhx0K1Wh04lxqDZVmWpmkD/osXL3pe40kx9cIsl8tWPp+nZptmszlw4Y8TJUSnyJRohRCuvlZfnMd18yjReeE1RinlsYnTe1RTgrp4h4eH1GWjokPU6NNsNqnJJshHkVIOCFDXdc+bRdd1S9d1l40SdO4gH0VdO7/zqRvaecxut2slEonI13IUprrGzOfzkFJifn6eumwqlQqEEFheXqauQF6/fo1arUbNyOVy+PXrFzX70ul0kEwm7detVgsfP34EANeYlP3Ro0e2zYtxjWt/fx8AcOvWLeoC+ucBgGvXrtm25eVlCCGwvb3t6DkhqFKnhWF3vCJMHz80TXOlLvo6DDQ1CyHsaOQclxAidCSi46Cvw+AVyZ3QcSs0TbMSiURglsrn83aZ4NVopvBiaiOmuuMvXbpEXTYqsly9epW6QlEqlbC3t4darYZcLodMJoO7d+/Sbr4YhgEAWFpaAgAUi0Vsbm6SXn+jXaFQCB3VxzGuRqPhORY4rlsmk6EuLC0todfrod1uUxfQXx358uULdF2HEAK6rkPXdQCAlBK6riObzdK3DUKVOi2oOi2orhoWFcIihPCMHsNwRsZut2uPRdW91WrVajaboSKIF6OOy2tW7tW8qNfr9mfyolwu2387j6E+b1imNmKqOi2IRqOB1dVVao6EimZwRJKwqJrvwoULWF1dxYcPHwAAP3/+BAAsLCwgm82iVCq53heGfxmXqrv7k9+Bhn508+LUqVPU5OL+/fsAANM0qQsLCwvU5MvUCnMY6p9179496gqNM00602dYlAArlQo2NzftVP3jxw8AQKFQiJTCFf8yLpXG/W5YdZxQ6TaAdrtti3uUxfmpFeaNGzeoyUWlUgHIrFLRarVQLBap2YVX7RZVBIpOp+M7245SG2IM41K1ud8Nu7e3BwC4fPkydUXi/fv31BQNmtunBWedRlEzdr/aTUo5dAYcVLsG+ZyoHRTa32vRPSz0WE6CfAp1bj+CrpvlqO3r9Tp12Xz9+tVVh9I1UWcd6sfURkx1R6t06USts3mlo7W1NYCsIXrhFWkVQT4nhmFA1/WB/p1OB9VqdegYvKDHchLkQz9TNBoNaJpGXUB/1QBDstHR0REA4MqVK9Rls76+DnismDx48ABPnz7F6dOnXXZPqFKniTt37rju7rCzTb8Z5bjxizx+9klCrwEcEVtlGGfzW81Ip9NDVwKEEFY6nXatdapIHfazz1lqGjaFGIYBIQQODw8Dd3+Y8WAYBtLpND5//jxStI/C1KZy9NNxuVzGixcvqIuZANvb2yiVShMXJaIKM5lMYm5uztXUTNAwjAHfcaDWzcLMSJnRqdVqA6sBE4Xm9mGoGZZXnaFqFS/fpKnX64EzRWZ06vV6qBn/OBlZmF7LNKNukTEMJVIqh2ObjW4vra2tIZlMjrS9xjCUyMJU64bnzp2zbcViEY1GA7u7u46ebmj96dfUOiMz20QWptrnVTOzVquFx48fo9lskp5u6IMCfi1I3MzsEFmYau1Qkc1mPXc3GOafoEXnMIQQ9uq9pmmhJzt0Z8GvhdkZoO/hNn1tGJF3fubm5qBpGjKZDJ49e4ZOp0O7MMw/EymVq68KAMDGxob94CvDjJtIwvz9+zcA4OXLlyM/HcMwYYgkTLWGqev68W1NMTNJpBozl8vBMAxe0mEmTiRhMseDaZp4+/Yt3r17h0ajASnlzAUDFmbMODg4wPr6Ov78+YMnT55ASolUKkW7nXhYmDHi4OAA169fhxACu7u7M/3wMwszJpimiZWVFZw5cwbtdnumRYmos3JmcmxtbaHX66FQKMy8KMHCjAemaaJWqyGRSODo6Mj+pkAymZzZJ/NZmDHg+/fv6PV6EEJgcXERnU4H3W4XiUQCGxsbM/kT3izMGPDt2zcAwO3bt3Hz5k2g/1jhmzdvAADPnz939Z8FWJgxYHFxkZqAvjjV12VnDRZmDDh//jzgeAjbyfz8PBKJBDWfeFiYMSCVSkFKiVqtNvDzffv7+74/6XKSYWHGBPWru1tbWzBNE6ZpIpfLQQiBhw8f0u4nHhZmTEilUvj06RMMw8DZs2exsrICADO7A8Q7P0ws4YjJxBIWJhNLWJhMLGFhMrGEhcnEEhYmE0tYmEws+R+UZackGdgxmgAAAABJRU5ErkJggg==\" width=\"166\" height=\"60\"\u003e\u003c/p\u003e\n\u003cp\u003ewhere \u003cem\u003eL\u003c/em\u003e is the maximum anterior\u0026ndash;posterior length, \u003cem\u003eW\u003c/em\u003e the mediolateral width, and \u003cem\u003eH\u003c/em\u003e the dorsoventral height of the measured brain region.\u003c/p\u003e\n\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\n \u003ch2\u003eNeuron Density\u003c/h2\u003e\n \u003cp\u003eThe determination of neuronal density (number of neurons per mm\u0026sup2;) followed the method of Triki et al. (\u003cspan class=\"CitationRef\"\u003e2020\u003c/span\u003e). The telencephalon and cerebellum were isolated and stored in phosphate-buffered saline (PBS) at 4\u0026deg;C until analysis. Each brain region was homogenized in isotonic saline, and cell nuclei were stained with DAPI (4\u0026rsquo;,6-diamidino-2-phenylindole). Fluorescent images were captured using a fluorescence microscope (Leica DMRA2; Leica Microsystems, Wetzlar, Germany), and DAPI-positive nuclei were quantified in ImageJ (Schneider et al., \u003cspan class=\"CitationRef\"\u003e2012\u003c/span\u003e) as a proxy for total cell number in each region.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\n \u003ch2\u003eData analysis\u003c/h2\u003e\n \u003cp\u003eAll statistical analyses were conducted using SPSS Statistics 26.0 (IBM, USA). Differences in lateralization (on the first three turning choices recorded during the egocentric spatial task) between wild and hatchery fish were analyzed using a binomial Generalized Linear Mixed Model (GLMM) with logit link-function. The model specified the turning choice (right/left) as a binary response variable, Group as a fixed effect, and ID as a random intercept to control for repeated measurements from the same individual. We did not include the trial as a fixed effect in these analyses since results indicated no or little effect. Spatial learning performance was assessed by comparing success rates and latencies across groups in the egocentric task, whereas cognitive flexibility was analyzed based on post-reversal success rates in the reversal learning phase. The dominant cognitive strategy was inferred by comparing latencies between egocentric and allocentric task conditions. Data normality was tested with the Shapiro\u0026ndash;Wilk test, and Levene\u0026rsquo;s test was used to verify homogeneity of variance. For normally distributed data, independent-sample \u003cem\u003et\u003c/em\u003e-tests were applied; otherwise, the Mann\u0026ndash;Whitney U test was used. All results are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard error (SE). Statistical significance was set at \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"RESULTS","content":"\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eBehavioral lateralization\u003c/h2\u003e \u003cp\u003eThe GLMM on lateralization revealed a significant effect of group on turning preference (β = -2.368, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.021). Wild fish showed a significant bias towards right turns, whereas hatchery-reared fish exhibited no significant directional preference (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section2\"\u003e \u003ch2\u003eSpatial cognitive ability\u003c/h2\u003e \u003cp\u003eWild fish exhibited significantly shorter latencies when navigating the maze compared to hatchery-reared fish (Mann\u0026ndash;Whitney \u003cem\u003eU\u003c/em\u003e test, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001; Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eA). In addition, wild individuals achieved a higher overall success rate in the egocentric spatial task (independent-samples \u003cem\u003et\u003c/em\u003e-test, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001; Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eB). Over the 7-day training period, daily success rates progressively increased in the wild group and remained consistently higher than those of hatchery-reared fish throughout all sessions (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eC).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003eCognitive flexibility\u003c/h2\u003e \u003cp\u003eIn the reversal learning test, where the correct door was reversed, wild fish achieved a significantly higher overall success rate than hatchery-reared fish (independent-samples \u003cem\u003et\u003c/em\u003e-test, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.038; Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eA). This performance advantage persisted throughout the entire testing phase (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003eB).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section2\"\u003e \u003ch2\u003eSpatial cognitive strategies\u003c/h2\u003e \u003cp\u003eBoth groups relied more effectively on an egocentric (self turn-based) strategy than on an allocentric (landmark-based) one, as indicated by shorter completion times under egocentric conditions. Wild fish took significantly longer to complete the maze in the allocentric task than in the egocentric task (Mann\u0026ndash;Whitney U test, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001; Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eA). Hatchery-reared fish also showed longer latencies under the allocentric condition, although the difference was not statistically significant (Mann\u0026ndash;Whitney U test, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.211; Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eB).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section2\"\u003e \u003ch2\u003eBrain size\u003c/h2\u003e \u003cp\u003eMorphometric analysis revealed no detectable differences in relative volumes of telencephalon and cerebellum (telencephalon: independent-samples t-test, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.20; cerebellum: Mann\u0026ndash;Whitney \u003cem\u003eU\u003c/em\u003e test, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.69; Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eA, B). The neuronal density (DAPI-positive cells per gram of tissue) was slightly higher on average in wild fish in both brain regions, but again, the differences were not significant (telencephalon: independent-samples \u003cem\u003et\u003c/em\u003e-test, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.39; cerebellum: Mann\u0026ndash;Whitney \u003cem\u003eU\u003c/em\u003e test, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.485; Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003eC, D).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"DISCUSSION","content":"\u003cdiv id=\"Sec20\" class=\"Section2\"\u003e \u003ch2\u003eBehavioral Lateralization\u003c/h2\u003e \u003cp\u003eIn the present study, wild marbled rockfish exhibited a pronounced right-turning bias, whereas hatchery-reared conspecifics did not. This difference in lateralization, i.e., the consistent preference for using one side of their body or sensory organs during specific behaviors (Zhao \u0026amp; Li, \u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e2016\u003c/span\u003e), could reflect differences in neural development and ecological experience. In natural habitats, where predation pressure and environmental complexity are high, lateralization can enhance performance in tasks requiring simultaneous vigilance and foraging.\u003c/p\u003e \u003cp\u003eBehavioral lateralization is widespread across vertebrates and invertebrates (Rogers \u0026amp; Andrew, \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2002\u003c/span\u003e) and is thought to improve cognitive efficiency by reducing decision-making time and enhancing environmental adaptability (Sovrano et al., \u003cspan citationid=\"CR52\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Rogers, \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2014\u003c/span\u003e, \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). In fishes with laterally positioned eyes, such asymmetry manifests as hemisphere specialization (Vallortigara and Rogers, \u003cspan citationid=\"CR56\" class=\"CitationRef\"\u003e2005\u003c/span\u003e), possibly facilitating multitasking during foraging (G\u0026uuml;nt\u0026uuml;rk\u0026uuml;n, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2012\u003c/span\u003e) and learning (Bisazza and Dadda, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2005\u003c/span\u003e; Dadda and Bisazza, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). For example, in \u003cem\u003eBrachyraphis episcopi\u003c/em\u003e, strongly lateralized individuals double their predation success compared with non-lateralized ones (Brown and Braithwaite, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). Conclusions on ecological effects of lateralization in marble rockfish are speculative at the current stage of research and future studies should explore the question in more detail.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section2\"\u003e \u003ch2\u003eSpatial Cognitive Ability\u003c/h2\u003e \u003cp\u003eWild marbled rockfish navigated mazes more rapidly and successfully than hatchery-reared individuals, indicating superior spatial learning and memory. These results reinforce the notion that environmental enrichment, through habitat complexity, sensory diversity, or social interactions, plays a pivotal role in developing cognitive competence (Rogers et al., \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2004\u003c/span\u003e; Diniz et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Previous work has demonstrated that structural enrichment stimulates neurogenesis and enhances spatial cognition in several species of hatchery-reared fish, e.g. Atlantic salmon (\u003cem\u003eSalmo salar\u003c/em\u003e) (Salvanes et al., \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2013\u003c/span\u003e), gibel carp (\u003cem\u003eCarassius gibelio\u003c/em\u003e) (Abreu et al., \u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e2019\u003c/span\u003e), and black rockfish (\u003cem\u003eSebastes schlegelii\u003c/em\u003e) (Zhang et al., \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Impoverished sensory- and structural environments in hatchery tanks may constrain neural development, leading to the cognitive deficits observed. Drawing from previous studies, addition of environmental enrichment could be one way to improve spatial learning abilities in the marbled rockfish.\u003c/p\u003e \u003cp\u003eSpatial cognition enables animals to navigate, locate resources, and select suitable habitats\u0026mdash;capabilities essential for survival and reproduction (Brown, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2003\u003c/span\u003e; Grieves and Jeffery, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Impaired spatial cognition has been implicated in the reduced behavioral adaptability and post-release survival of hatchery-reared fish (Johnsson et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2014\u003c/span\u003e; Araki et al., \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Ebbesson and Braithwaite, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). Environmental conditions during development profoundly shape these abilities (Brockmark et al., 2012; Dalesman and Lukowiak, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). For example, three-spined sticklebacks from structurally complex rivers exhibit larger telencephalon volumes than conspecifics from homogeneous lakes (Ahmed et al., \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2017\u003c/span\u003e), and angelfish (\u003cem\u003ePterophyllum scalare\u003c/em\u003e) reared in enriched environments show greater telencephalic neuron density and improved learning performance (Diniz et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2020\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec22\" class=\"Section2\"\u003e \u003ch2\u003eSpatial Cognitive Strategies\u003c/h2\u003e \u003cp\u003eAnimals differ markedly in how they perceive and respond to spatial information, often employing distinct navigational strategies\u0026mdash;egocentric (self-referenced) or allocentric (landmark-referenced), depending on environmental cue reliability and varying among species (Odling-Smee and Braithwaite, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e2003a\u003c/span\u003e,\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003eb\u003c/span\u003e; Sovrano et al., \u003cspan citationid=\"CR51\" class=\"CitationRef\"\u003e2020\u003c/span\u003e; Yashina et al., \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Warburton, \u003cspan citationid=\"CR58\" class=\"CitationRef\"\u003e1990\u003c/span\u003e; Brown et al., \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2007\u003c/span\u003e). Thus, different spatial cognitive strategies could represent adaptive trade-offs shaped by environmental demands.\u003c/p\u003e \u003cp\u003eBoth hatchery-reared and wild marbled rockfish performed better under egocentric conditions than under landmark (allocentric) conditions, suggesting a general reliance on turn-based strategies. Artificial landmarks (e.g., plastic plants) may have elicited neophobic or avoidance responses, thus interfering with their function as spatial cues. Environmental stability also shapes navigational strategy: animals in dynamic habitats often favor egocentric strategies for rapid adaptation, whereas those in stable environments depend more on fixed landmark cues (Biegler and Morris, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e1996\u003c/span\u003e). Wild marbled rockfish inhabit structurally complex, variable reef environments where egocentric navigation may be advantageous for rapid decision-making. In contrast, hatchery fish raised in homogenous tanks lack opportunities to form allocentric representations. Future studies incorporating graded enrichment and naturalistic spatial cues could clarify how environmental complexity modulates the ontogeny and flexibility of navigational strategies in reef fishes.\u003c/p\u003e \u003cdiv id=\"Sec23\" class=\"Section3\"\u003e \u003ch2\u003eCognitive Flexibility\u003c/h2\u003e \u003cp\u003eCognitive flexibility, capacity to modify learned behaviors when environmental contingencies change, is essential for adaptive decision-making and reversal learning tasks are widely used to quantify this ability (Prado et al., \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Benzina et al., \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Wild marbled rockfish exhibited higher reversal-learning success than hatchery-reared individuals, demonstrating greater flexibility in updating spatial learning strategies. Conversely, hatchery fish often persisted along incorrect routes, suggesting difficulty in behavioral inhibition and rule shifting. Such deficits likely result from the monotonous and predictable hatchery environment, which lacks the variable stimuli that foster behavioral adaptability. In contrast, wild fish experience constant environmental change, predation threats, and resource variability, all of which promote flexible learning (Sommer-Trembo et al., \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). Similar habitat-related effects have been reported in sticklebacks, where individuals from fluctuating river habitats employ multiple spatial strategies, whereas pond-dwelling conspecifics rely on a single, fixed approach (Girvan and Braithwaite, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e1998\u003c/span\u003e). Overall, environmental heterogeneity appears to stimulate experience-dependent plasticity in cognition. The superior flexibility observed in wild rockfish thus likely reflects adaptive neural tuning to environmental complexity, highlighting the need for environmental enrichment in hatchery protocols to mitigate cognitive deficiency.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec24\" class=\"Section2\"\u003e \u003ch2\u003eBrain Volume and Neuronal Density\u003c/h2\u003e \u003cp\u003eThe brain is the central organ governing cognition, with the telencephalon mediating higher-order processing and the cerebellum coordinating balance and motor control. Several previous studies have reported reduced brain volumes in hatchery-reared fish compared with wild conspecifics, e.g. in rainbow trout (\u003cem\u003eOncorhynchus mykiss\u003c/em\u003e) and Chinook salmon (\u003cem\u003eO. tshawytscha\u003c/em\u003e) (Marchetti and Nevitt, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2003\u003c/span\u003e; Kihslinger et al., \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e2006\u003c/span\u003e). Previous studies on brain-size selected guppies (\u003cem\u003ePoecilia reticulata\u003c/em\u003e) also indicate that brain size can be associated with spatial cognition tasks (Kotrschal et al. \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). In our study, however, wild and hatchery-reared marbled rockfish exhibited similar mean telencephalon and cerebellum volumes.\u003c/p\u003e \u003cp\u003eSimilarly, our histological analysis revealed no significant difference in neuronal density. However, subtle cellular-level variations such as total neuron number, soma size, or neuropil volume, undetectable using the current assessment protocol, may still underlie cognitive differences. We therefore do not reject the possibility that there may be an underlying neurological explanation to the observed cognitive differences. Future research employing advanced neuroimaging or molecular techniques could help elucidate such fine-scale neural correlates of cognition and the wild vs. hatchery-reared marbled rockfish system could be a suitable model system worthy of further investigation.\u003c/p\u003e \u003c/div\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003eThis study provides comprehensive evidence that captivity impairs spatial cognition, behavioral lateralization, and cognitive flexibility in marbled rockfish. Wild individuals displayed pronounced lateralization, faster and more accurate spatial navigation, and superior reversal-learning performance, consistent with enhanced adaptability to dynamic reef environments. These findings imply the critical role of habitat heterogeneity in shaping cognitive and neural development in fish and highlight the potential of environmental enrichment to improve behavioral competence and post-release survival in hatchery-reared reef species.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor contributions\u0026nbsp;\u003c/strong\u003eC.L.: writing \u0026ndash; original draft, formal analysis, visualization, investigation. H.G.: writing \u0026ndash; original draft, writing \u0026ndash; review \u0026amp; editing, supervision, project administration, conceptualization, methodology, funding acquisition. Y.O.: investigation, visualization, validation, methodology, formal analysis, data curation. J.N.: writing \u0026ndash; review \u0026amp; editing, visualization, formal analysis. Y.H.: investigation. C.Z.: investigation. X.Z.: conceptualization. All authors have read and agreed to the published version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003eThis study was supported by the Natural Science Foundation of National Natural Science Foundation of China (32573485 and 32102755), Natural Science Foundation of Zhejiang Province (LGN22C190015).\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAbreu CC, Fernandes TN, Henrique EP, Pereira PDC, Marques SB, Herdeiro SLS, Oliveira FRR, Magalh\u0026atilde;es NGM, Anthony DC, Guerreiro-Diniz C, Melo MAD, Diniz DG, Picanco-Diniz CW (2019) Small-scale environmental enrichment and exercise enhance learning and spatial memory of Carassius auratus, and increase cell proliferation in the telencephalon: an exploratory study. Braz J Med Biol Res 52(5):e8026. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1590/1414-431X20198026\u003c/span\u003e\u003cspan address=\"10.1590/1414-431X20198026\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAdriaenssens B, Johnsson JI (2011) Learning and context-specific exploration behaviour in hatchery and wild brown trout. Appl Anim Behav Sci 132(1\u0026ndash;2):90\u0026ndash;99. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.applanim.2011.03.005\u003c/span\u003e\u003cspan address=\"10.1016/j.applanim.2011.03.005\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAhmed NI, Thompson C, Bolnick DI, Stuart YE (2017) Brain morphology of the threespine stickleback (\u003cem\u003eGasterosteus aculeatus\u003c/em\u003e) varies inconsistently with respect to habitat complexity: a test of the Clever Foraging Hypothesis. Ecol Evol 7(10). \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1002/ece3.2918\u003c/span\u003e\u003cspan address=\"10.1002/ece3.2918\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBisazza A, Dadda M (2005) Enhanced schooling performance in lateralized fishes. Proceedings of the Royal Society B 272(1573): 1677\u0026ndash;1681. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1098/rspb.2005.3145\u003c/span\u003e\u003cspan address=\"10.1098/rspb.2005.3145\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAraki H, Berejikian BA, Ford MJ, Blouin MS (2008) Fitness of hatchery-reared salmonids in the wild. Evol Appl 1:342\u0026ndash;355. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/j.1752-4571.2008.00026.x\u003c/span\u003e\u003cspan address=\"10.1111/j.1752-4571.2008.00026.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBarmack NH (2003) Central vestibular system: vestibular nuclei and posterior cerebellum. Brain Res Bull 60(5\u0026ndash;6):511\u0026ndash;541. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S0361-9230(03)00055-8\u003c/span\u003e\u003cspan address=\"10.1016/S0361-9230(03)00055-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBenzina N, N\u0026rsquo;Diaye K, Pelissolo A, Mallet L, Burgui\u0026egrave;re E (2021) A cross-species assessment of behavioral flexibility in compulsive disorders. Commun Biology 4(1):96. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1038/s42003-020-01611-y\u003c/span\u003e\u003cspan address=\"10.1038/s42003-020-01611-y\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBrockmark S, Adriaenssens B, Johnsson I (2010) Less is more: density influences the development of behavioural life skills in trout. Proceedings of the Royal Society B 277(1696): 3035\u0026ndash;3043\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBrown AA, Spetch ML, Hurd PL (2007) Growing in circles: rearing environment alters spatial navigation in fish. Psychol Sci 18(7):569\u0026ndash;573. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1098/rspb.2010.0561\u003c/span\u003e\u003cspan address=\"10.1098/rspb.2010.0561\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBrown AD, Sisneros JA, Jurasin T, Nguyen C, Coffin AB (2013) Differences in lateral line morphology between hatchery-and wild-origin steelhead. PLoS ONE 8(3):e59162. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1371/journal.pone.0059162\u003c/span\u003e\u003cspan address=\"10.1371/journal.pone.0059162\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBrown C (2003) Habitat-predator association and avoidance in rainbowfish (\u003cem\u003eMelanotaenia\u003c/em\u003e spp. Ecol Freshw Fish 12(2):118\u0026ndash;126. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1034/j.1600-0633.2003.00007.x\u003c/span\u003e\u003cspan address=\"10.1034/j.1600-0633.2003.00007.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBrown C, Braithwaite VA (2005) Effects of predation pressure on the cognitive ability of the poeciliid \u003cem\u003eBrachyraphis episcopi\u003c/em\u003e. Behav Ecol 16(2):482\u0026ndash;487. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1093/beheco/ari016\u003c/span\u003e\u003cspan address=\"10.1093/beheco/ari016\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBiegler R, Morris RG (1996) Landmark stability: studies exploring whether the perceived stability of the environment influences spatial representation. J Exp Biol 199(1):187\u0026ndash;193. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1242/jeb.199.1.187\u003c/span\u003e\u003cspan address=\"10.1242/jeb.199.1.187\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen L, Wang HX, Xu KD, Lv ZY, Huang B, Li Z, Liang J, Zhou YD, Li PF, Liu LW (2022) Analysis of current situation of proliferation and release of island and reef fishes in the coastal waters of Zhejiang. J Zhejiang Ocean University(Natural Science) 41(05):459\u0026ndash;465\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDadda M, Bisazza A (2006) Does brain asymmetry allow efficient performance of simultaneous tasks? Animal Behaviour. 72(3):523\u0026ndash;529. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.anbehav.2005.10.019\u003c/span\u003e\u003cspan address=\"10.1016/j.anbehav.2005.10.019\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDalesman S, Lukowiak K (2011) Social snails: the effect of social isolation on cognition is dependent on environmental context. J Exp Biol 214(24):4179\u0026ndash;4185. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1242/jeb.064857\u003c/span\u003e\u003cspan address=\"10.1242/jeb.064857\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDiniz DG, de Siqueira LS, Henrique EP, Pereira PDC, Diniz CG, de Abreu CC, de Morais Magalh\u0026atilde;es NG, da Silva Soares GL, Guimar\u0026atilde;es Paix\u0026atilde;o PE, Meneses JL, do Couto MVS, da, Costa Sousa S, dos Santos Cunha F, Pican\u0026ccedil;o Diniz CW, Fujimoto RY (2020) Environmental enrichment increases the number of telencephalic but not tectal cells of angelfish (\u003cem\u003ePterophyllum scalare\u003c/em\u003e): an exploratory investigation using optical fractionator. Environmental Biology of Fishes 103: 847\u0026ndash;857\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDunlap KD (2016) Fish neurogenesis in context: assessing environmental influences on brain plasticity within a highly labile physiology and morphology. Brain Behav Evol 87(3):156\u0026ndash;166. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1159/000446907\u003c/span\u003e\u003cspan address=\"10.1159/000446907\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEbbesson L, Braithwaite VA (2012) Environmental effects on fish neural plasticity and cognition. J Fish Biol 81(7):2151\u0026ndash;2174. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/j.1095-8649.2012.03486.x\u003c/span\u003e\u003cspan address=\"10.1111/j.1095-8649.2012.03486.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGe S, Sailor KA, Ming G, Song H (2008) Synaptic integration and plasticity of new neurons in the adult hippocampus. J Physiol 586(16):3759\u0026ndash;3765. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1113/jphysiol.2008.155655\u003c/span\u003e\u003cspan address=\"10.1113/jphysiol.2008.155655\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGirvan JR, Braithwaite VA (1998) Population differences in spatial learning in three-spined sticklebacks. Proceedings of the Royal Society of London B 265(1399): 913\u0026ndash;918. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1098/rspb.1998.0378\u003c/span\u003e\u003cspan address=\"10.1098/rspb.1998.0378\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGrieves RM, Jeffery KJ (2017) The representation of space in the brain. Behavioural Processes 135: 113\u0026ndash;131. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.beproc.2016.12.012\u003c/span\u003e\u003cspan address=\"10.1016/j.beproc.2016.12.012\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eG\u0026uuml;nt\u0026uuml;rk\u0026uuml;n O (2012) The convergent evolution of neural substrates for cognition. Psychol Res 76(2):212\u0026ndash;219\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGuo HY, N\u0026auml;slund J, Thomassen RT, Larsen MH (2022) Social isolation affects intra-specific interaction behaviour and reduces the size of the cerebellar brain region in juvenile Atlantic salmon \u003cem\u003eSalmo salar\u003c/em\u003e. J Fish Biol 101(3):711\u0026ndash;721. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/jfb.15142\u003c/span\u003e\u003cspan address=\"10.1111/jfb.15142\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGuo HY, Zhang XF, N\u0026auml;slund J, Peng LY, Liu CH, Tian MJ, Chai XJ, Zhang DY, Zhang XM (2022) Differences in external morphology, body composition and swimming performance between hatchery-and wild-origin marbled rockfish (\u003cem\u003eSebastiscus marmoratus\u003c/em\u003e). Front Mar Sci 9:912129. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3389/fmars.2022.912129\u003c/span\u003e\u003cspan address=\"10.3389/fmars.2022.912129\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHuber R, van Staaden MJ, Kaufan LS, Liem KF (1997) Microhabitat use, trophic patterns, and the evolution of brain structure in African cichlids. Brain, Behavior and Evolution 50,(3), 167\u0026ndash;182\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJohnsson JI, Brockmark S, N\u0026auml;slund J (2014) Environmental effects on behavioural development consequences for fitness of captive-reared fishes in the wild. J Fish Biol 85(6):1946\u0026ndash;1971. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/jfb.12547\u003c/span\u003e\u003cspan address=\"10.1111/jfb.12547\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKihslinger RL, Nevitt GA (2006) Early rearing environment impacts cerebellar growth in juvenile salmon. Journal of Experimental Biology, 2006, 209(3): 504\u0026ndash;509. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1242/jeb.02019\u003c/span\u003e\u003cspan address=\"10.1242/jeb.02019\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKihslinger RL, Lema SC, Nevitt GA (2006) Environmental rearing conditions produce forebrain differences in wild Chinook salmon \u003cem\u003eOncorhynchus tshawytscha\u003c/em\u003e. Comp Biochem Physiol A: Mol Integr Physiol 145(2):145\u0026ndash;151. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.cbpa.2006.06.041\u003c/span\u003e\u003cspan address=\"10.1016/j.cbpa.2006.06.041\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKotrschal A, Corral-Lopez A, Amcoff M, Kolm N (2015) A larger brain confers a benefit in a spatial mate search learning task in male guppies. Behav Ecol 26(2):527\u0026ndash;532. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1093/beheco/aru227\u003c/span\u003e\u003cspan address=\"10.1093/beheco/aru227\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLorenzen K, Beveridge MC, Mangel M (2012) Cultured fish: integrative biology and management of domestication and interactions with wild fish. Biol Rev 87(3):639\u0026ndash;660. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/j.1469-185X.2011.00215.x\u003c/span\u003e\u003cspan address=\"10.1111/j.1469-185X.2011.00215.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLucon-Xiccato T, Bisazza A (2017) Sex differences in spatial abilities and cognitive flexibility in the guppy. Anim Behav 123:53\u0026ndash;60. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.anbehav.2016.10.026\u003c/span\u003e\u003cspan address=\"10.1016/j.anbehav.2016.10.026\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMakino H, Masuda R, Tanaka M (2015) Environmental stimuli improve learning capability in striped knifejaw juveniles: the stage-specific effect of environmental enrichment and the comparison between wild and hatchery-reared fish. Fish Sci 81:1035\u0026ndash;1042\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMarchetti MP, Nevitt GA (2003) Effects of hatchery rearing on brain structures of rainbow trout, \u003cem\u003eOncorhynchus mykiss\u003c/em\u003e. Environ Biol Fish 66:9\u0026ndash;14\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMazzei R, Lampe M, Ohnesorge A, Pajot A, Soares MC, Bshary R (2019) Ecological differences in the facultative Caribbean cleaning goby \u003cem\u003eElacatinus prochilos\u003c/em\u003e do not predict learning performance in discriminatory two-choice tasks. Anim Cogn 22(6):1039\u0026ndash;1050. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s10071-019-01295-w\u003c/span\u003e\u003cspan address=\"10.1007/s10071-019-01295-w\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eN\u0026auml;slund J (2021) Reared to become wild-like: addressing behavioral and cognitive deficits in cultured aquatic animals destined for stocking into natural environments-a critical review. Bull Mar Sci 97(4):489\u0026ndash;538. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.5343/bms.2020.0039\u003c/span\u003e\u003cspan address=\"10.5343/bms.2020.0039\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOdling-Smee L, Braithwaite VA (2003a) The role of learning in fish orientation. Fish Fish 4(3):235\u0026ndash;246. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1046/j.1467-2979.2003.00127.x\u003c/span\u003e\u003cspan address=\"10.1046/j.1467-2979.2003.00127.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOdling-Smee L, Braithwaite VA (2003b) The influence of habitat stability on landmark use during spatial learning in the three-spined stickleback. Anim Behav 65(4):701\u0026ndash;707. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1006/anbe.2003.2082\u003c/span\u003e\u003cspan address=\"10.1006/anbe.2003.2082\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePillans RD, Bearham D, Boomer A, Downie R, Patterson TA, Thomson DP, Babcock R (2014) Multi year observations reveal variability in residence of a tropical demersal fish, \u003cem\u003eLethrinus nebulosus\u003c/em\u003e: implications for spatial management. PLoS One, 2014, 9(9): e105507. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1371/journal.pone.0105507\u003c/span\u003e\u003cspan address=\"10.1371/journal.pone.0105507\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePoucet B (1993) Spatial cognitive maps in animals: new hypotheses on their structure and neural mechanisms. Psychol Rev 100(2):163\u0026ndash;182. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1037/0033-295X.100.2.163\u003c/span\u003e\u003cspan address=\"10.1037/0033-295X.100.2.163\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePrado VF, Janickova H, Al-Onaizi MA, Prado MA (2017) Cholinergic circuits in cognitive flexibility. Neuroscience 345:130\u0026ndash;141. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.neuroscience.2016.09.013\u003c/span\u003e\u003cspan address=\"10.1016/j.neuroscience.2016.09.013\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eQi YL, Liu CH, Yuan GZ, Guo HY, N\u0026auml;slund J, Wang YC, Ru JF, Ou YY, Chai XJ, Zhang XM (2024) Disparities in body color adaptability and ambient light color preference between wild and hatchery-reared marbled rockfish (\u003cem\u003eSebastiscus marmoratus\u003c/em\u003e). Animals 14(11):1701. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/ani14111701\u003c/span\u003e\u003cspan address=\"10.3390/ani14111701\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRogers LJ (2014) Asymmetry of brain and behavior in animals: Its development, function, and human relevance. genesis 52(6): 555\u0026ndash;571. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1002/dvg.22741\u003c/span\u003e\u003cspan address=\"10.1002/dvg.22741\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRogers LJ (2021) Brain lateralization and cognitive capacity. Animals 11(7): 1996. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/ani11071996\u003c/span\u003e\u003cspan address=\"10.3390/ani11071996\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRogers LJ, Andrew R (2002) Comparative vertebrate lateralization. Cambridge University Press, 2002\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRogers LJ, Zucca P, Vallortigara G (2004) Advantages of having a lateralized brain. Proceedings of the Royal Society of London B, 2004, 271(suppl_6): S420-S422. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1098/rsbl.2004.0200\u003c/span\u003e\u003cspan address=\"10.1098/rsbl.2004.0200\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSalvanes AGV, Moberg O, Ebbesson LO, Nilsen TO, Jensen KH, Braithwaite VA (2013) Environmental enrichment promotes neural plasticity and cognitive ability in fish. Proceedings of the Royal Society B 280(1767): 20131331. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1098/rspb.2013.1331\u003c/span\u003e\u003cspan address=\"10.1098/rspb.2013.1331\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSchneider CA, Rasband WS, Eliceiri KW (2012) NIH image to ImageJ: 25 years of image analysis. Nature Methods, 2012, 9, 671\u0026ndash;675\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSheenaja KK, Thomas KJ (2011) Influence of habitat complexity on route learning among different populations of climbing perch (\u003cem\u003eAnabas testudineus\u003c/em\u003e Bloch, 1792). Mar Freshw Behav Physiol 44:349\u0026ndash;358. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1080/10236244.2011.642503\u003c/span\u003e\u003cspan address=\"10.1080/10236244.2011.642503\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSommer-Trembo C, Petry AC, Silva GG, Vurusic SM, Gismann J, Baier J, Krause S, de Araujo Cardoso Iorio J, Riesch R, Plath M (2017) Predation risk and abiotic habitat parameters affect personality traits in extremophile populations of a neotropical fish (\u003cem\u003ePoecilia vivipara\u003c/em\u003e). Ecol Evol 7(16):6570\u0026ndash;6581. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1002/ece3.3165\u003c/span\u003e\u003cspan address=\"10.1002/ece3.3165\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSovrano VA, Baratti G, Lee SA (2020) The role of learning and environmental geometry in landmark-based spatial reorientation of fish (\u003cem\u003eXenotoca eiseni\u003c/em\u003e). PLoS ONE 15(3):e229608. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1371/journal.pone.0229608\u003c/span\u003e\u003cspan address=\"10.1371/journal.pone.0229608\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSovrano VA, Baratti G, Potrich D (2018) A detour task in four species of fishes. Front Psychol 9:2341. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3389/fpsyg.2018.02341\u003c/span\u003e\u003cspan address=\"10.3389/fpsyg.2018.02341\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSundstr\u0026ouml;m LF, Johnsson JI (2001) Experience and social environment influence the ability of young brown trout to forage on live novel prey. Anim Behav 61(1):249\u0026ndash;255. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1006/anbe.2000.1593\u003c/span\u003e\u003cspan address=\"10.1006/anbe.2000.1593\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTriki Z, Emery Y, Teles MC, Oliveira RF, Bshary R (2020) Brain morphology predicts social intelligence in wild cleaner fish. Nat Commun 11(1):6423. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1038/s41467-020-20130-2\u003c/span\u003e\u003cspan address=\"10.1038/s41467-020-20130-2\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eValente AE, Huang K, Portugues R, Engert F (2012) Ontogeny of classical and operant learning behaviors in zebrafish. Learn Mem 19(4):170\u0026ndash;177. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://www.learnmem.org/cgi/doi/\u003c/span\u003e\u003cspan address=\"http://www.learnmem.org/cgi/doi/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1101/lm.025668.112\u003c/span\u003e\u003cspan address=\"10.1101/lm.025668.112\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eVallortigara G, Rogers L (2005) Survival with an asymmetrical brain: advantages and disadvantages of cerebral lateralization. Behav Brain Sci 28(4):575\u0026ndash;588. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1017/S0140525X0528010X\u003c/span\u003e\u003cspan address=\"10.1017/S0140525X0528010X\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang ZH, Zhong JM, Zhang SY, Wang K, Lin J, Zhang J, Shen H (2019) Habitat use of juvenile rockfish (\u003cem\u003eSebastiscus marmoratus\u003c/em\u003e) in mussel farming waters: a preliminary study. J Fisheries China 43(09):1900\u0026ndash;1913\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWarburton K (1990) The use of local landmarks by foraging goldfish. Anim Behav 40(3):500\u0026ndash;505. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S0003-3472(05)80530-5\u003c/span\u003e\u003cspan address=\"10.1016/S0003-3472(05)80530-5\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWu CW (1999) Biological Studies on \u003cem\u003eSebastiscus marmoratus\u003c/em\u003e off Zhoushan. J Zhejiang Ocean Univ (Natural Science) (03): 185\u0026ndash;190\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYashina K, Tejero-Cantero L, Herz A, Baier H (2019) Zebrafish exploit visual cues and geometric relationships to form a spatial memory. iScience 19(C):119\u0026ndash;134\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang ZH, Fu YQ, Shen FY, Zhang Z, Guo HY, Zhang XM (2021) Barren environment damages cognitive abilities in fish: Behavioral and transcriptome mechanisms. Sci Total Environ 794:148805. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.scitotenv.2021.148805\u003c/span\u003e\u003cspan address=\"10.1016/j.scitotenv.2021.148805\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhao DP, Li BG (2016) Current research status on behavioral laterality in Chinese nonhuman primates. Acta Theriol Sinica 036(002):232\u0026ndash;240. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.16829/j.slxb.201602012\u003c/span\u003e\u003cspan address=\"10.16829/j.slxb.201602012\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"animal-cognition","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"anco","sideBox":"Learn more about [Animal Cognition](http://link.springer.com/journal/10071)","snPcode":"10071","submissionUrl":"https://submission.nature.com/new-submission/10071/3","title":"Animal Cognition","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Sebastiscus marmoratus, behavioral lateralization, spatial cognition, cognitive flexibility, brain morphology","lastPublishedDoi":"10.21203/rs.3.rs-8422304/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8422304/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eHatchery-reared fish typically display marked behavioral differences compared to wild conspecifics. For reef-dwelling species, spatial cognition is critical to navigate complex and dynamic habitats. If captive rearing influences these abilities in fish reared for release into nature, then optimization of rearing environments and practices may be necessary. We compared hatchery-reared and wild marbled rockfish (\u003cem\u003eSebastiscus marmoratus\u003c/em\u003e) in laboratory spatial cognition tests aimed at investigating differences in navigation strategies, behavioral lateralization, and cognitive flexibility. These tests were complemented by neuroanatomical analyses of brain regions involved in spatial processing. Hatchery-reared fish showed no consistent turning directionality, whereas wild fish had a general population-level lateralization (right-turning bias). In maze tests, wild fish navigated significantly faster and achieved higher success rates than hatchery fish. During reversal learning, wild fish adapted more efficiently, demonstrating better cognitive flexibility. Both hatchery-reared and wild fish predominantly relied on egocentric (turn-based) strategies, with limited use of allocentric (landmark-based) cues. No significant differences were detected in the relative volumes of the telencephalon or cerebellum, or in neuronal density. These findings indicate that captive rearing can impair spatial cognition and behavioral flexibility in fish, which could reduce environmental adaptability and may help explain the poor post-release survival of hatchery-reared reef species.\u003c/p\u003e","manuscriptTitle":"Cognitive costs of captivity: hatchery-reared marbled rockfish have impaired spatial cognition","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-29 18:51:55","doi":"10.21203/rs.3.rs-8422304/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"57397203137414525811548637049713730545","date":"2026-04-24T14:51:19+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-16T18:01:09+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"53829114004565104239711783702331433522","date":"2026-03-12T14:44:18+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"278745416855069966599511853446494815312","date":"2026-03-04T09:22:46+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-01-27T18:53:44+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-12-23T12:50:27+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-12-23T12:44:55+00:00","index":"","fulltext":""},{"type":"submitted","content":"Animal Cognition","date":"2025-12-22T07:35:55+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"animal-cognition","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"anco","sideBox":"Learn more about [Animal Cognition](http://link.springer.com/journal/10071)","snPcode":"10071","submissionUrl":"https://submission.nature.com/new-submission/10071/3","title":"Animal Cognition","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"0bbc5edc-0eca-4b76-8a8e-6316f909900a","owner":[],"postedDate":"January 29th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-01-29T18:51:56+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-29 18:51:55","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8422304","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8422304","identity":"rs-8422304","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}