Does the fishing pressure induce fish to mature early? An evaluation of the reproductive biology of Nemipterus japonicus (Bloch, 1791) from the Malabar Coast of India

Does the fishing pressure induce fish to mature early? An evaluation of the reproductive biology of Nemipterus japonicus (Bloch, 1791) from the Malabar Coast of India | 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 Does the fishing pressure induce fish to mature early? An evaluation of the reproductive biology of Nemipterus japonicus (Bloch, 1791) from the Malabar Coast of India V. Mahesh, P. K. Asokan, T. M. Najmudeen, K. Vinod, N. R. Kalavathi, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4544806/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract In fisheries management, a comprehensive comprehension of the reproductive biology of fish species is imperative, with specific emphasis on factors such as sexual maturation, the dynamics of the reproductive cycle, and the quantitative assessment of fecundity. To elucidate the reproductive dynamics of Nemipterus japonicus captured along the Malabar coast, encompassing parameters such as the sex ratio, sexual maturation, fecundity, and reproductive periodicity, a rigorous investigation was conducted spanning the period from 2017 to 2021. Sampled individuals of N. japonicus exhibited total lengths ranging from 5.5 to 35.2 cm. The exponent value (b = 2.991) observed in this current study exhibited a high degree of proximity to 3, indicative of an isometric growth pattern. The collective sex ratio stood at 1:1.3, signifying a higher prevalence of females than males. Attainment of 50% sexual maturation (L m50 ) occurred at a total length of 15 cm for males and 15.5 cm for females which is earlier than the reported length. Monthly changes in the gonadosomatic index exhibited elevated values from September to December, reaching their zenith in October. The study ascertained N. japonicus matured significantly earlier than in the last decade and the spawning season shifted to lower temperature months for better reproductive output along the south-west coast of India. Nemipterus japonicus Length-weight Early maturity Spawning cycle Minimum legal size Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1. Introduction Nemipterus japonicus , often called Japanese threadfin bream belongs to the Nemipteridae family and constitutes a vital component of the demersal fish catches caught primarily by bottom trawl fishing. Most Nemipterus species usually inhabit areas close to sandy or muddy seabeds, at depths ranging from 5 to 80 m (Russell 1993 ; Kerdgari et al. 2009 ). A total of ten species from the Nemipterus genus have been documented in the waters of India. (Barman and Mishra 2009 ; Mahesh et al. 2022 ), of which N. randalli and N. japonicus are the predominant species along the Kerala coast. The average catch of Nemipterus spp. in Kerala is 40,000 tonnes which contributed 37% to the demersal fish landings and 7% to the total fish landings of the state (NMFDC 2017–2022). Due to its affordable price and meat quality, Japanese threadfin seabream ranks among the highly favoured and economically significant edible fish species, especially for surimi production. Regulations are based on the reproductive characteristics of species subject to the greatest fishing pressure. Knowledge of reproductive parameters encompassing the length-weight correlation, sex ratio dynamics, reproductive periodicity patterns, and the peak spawning season is essential for determining the closure of the fishing season and minimum harvest sizes. Owing to their significant implications within the realm of fisheries, a plethora of investigations have been undertaken concerning the length-weight relationship, as evidenced by scholarly contributions such as those by Murty ( 1984 ); Bakhsh ( 1994 ); Zacharia ( 1998 ); Rajkumar et al. ( 2003 ); Manojkumar ( 2004 ) and comprehensive investigations into diverse facets of nemipterid biology, with specific emphasis on Nemipterus japonicus , have been pursued. This scholarly exploration is evident in works by Kuthalingam ( 1965 ); Krishnamoorthi ( 1971 ); Vinci ( 1982 ); Murty ( 1984 ); Rao ( 1989 ); Gopal and Vivekanandan ( 1991 ); Rajkumar et al. ( 2003 ); Manojkumar ( 2004 ); Kizhakudan et al. ( 2008 ) along the Indian coast. A dearth of investigations on the length-weight relationship and reproductive biology of Nemipterus japonicus was observed along the Malabar coast. The current research endeavours to fill this gap by undertaking an evaluation of the length-weight relationship and reproductive biology of Nemipterus japonicus (Bloch 1791 ) along the Malabar Coast, thereby facilitating an in-depth comprehension of the species' reproductive cycle. 2. Materials and methods Between 2017 and 2022, a total of 5,970 Nemipterus japonicus encompassing a spectrum of total lengths varying from 5.5 to 35 cm were meticulously acquired from the five prominent fishing harbours of Kasaragod, Kannur, Calicut, and Malappuram districts situated along the south-eastern periphery of the Arabian Sea (Fig. 1 ). The specimens were collected every 10 days, landed from trawl boats, except in July, when mechanised fishing vessels are prohibited from operating. The specimens obtained were expeditiously preserved within insulated ice containers and transferred to the laboratory located at the Calicut Regional Station of the Central Marine Fisheries Research Institute, facilitating their subsequent in-depth examination and scholarly analysis. 2.1. Length-weight allometry The total length (TL) and body weight of all individual fish were meticulously measured with a precision of 1 mm and 0.1 g, respectively. The association between length and weight was quantified through the application of the formula denoted as W = a(L) b , where W signifies the total body weight in grams, L represents the total length in centimeters, 'a' embodies the coefficient of body weight, and 'b' denotes the exponent signifying allometric growth, as stipulated by Le Cren ( 1951 ). To compare the correlation between the length and weight of both male and female specimens, an analysis of covariance (ANCOVA) methodology was employed, as detailed by Snedecor and Cochran ( 1967 ). 2.2. Reproductive biology Sex ratios were derived from monthly estimates of male and female numbers within the sample. The categorization of fish maturity phases hinged upon evaluating the spatial occupancy of the testes or ovaries and their macroscopic attributes. Employing the delineations outlined by the International Council for the Exploration of the Sea (ICES) in Lovern and Wood's seminal work from 1937, the gonadal stages were delineated as immature, virgin developing/spent recovering, early maturing, late maturing, mature, running, and spent. Stage III onwards is considered as mature fish. The weight of gonads was measured to the nearest 0.01 g. To ascertain fecundity, the ovaries were conserved in customised Gilson's fluid (Bagenal and Braum 1978 ). The fraction of mature fish in each length class was logistically fitted to calculate the length at first maturity (L m50 ) (King 2007 ). The calculation of the gonadosomatic index (GSI) was conducted by factoring in both the weight of the gonads and the total weight of the fish, employing the subsequent formula: GSI = (GW/SW) * 100, wherein GW and SW correspond to the gonadal and somatic weights, respectively. Excess moisture was removed from preserved ovaries and segments extracted from the anterior, middle, and posterior portions of ovaries exhibiting mature and running characteristics were employed as subsamples. Fecundity (F) was quantified through the application of the subsequent formula: F = [(Nss×Wo) /Wss], wherein Nss symbolizes the oocyte count within the subsample, Wo denotes the overall weight of the ovary, and Wss represents the cumulative weight of the subsample. 3. Results 3.1. Length-weight allometric relationship In order to establish the length-weight allometric relationship, a dataset encompassing 5,970 fish specimens was employed, characterized by a range of total lengths (TL) spanning from 5.5 to 35.2 cm, and corresponding total weights (W) spanning from 2.2 to 498 g. All data were pooled and a common relationship was obtained for all sampled fishes including the undetermined sex specimens. Within this comprehensive dataset (illustrated in Fig. 2 ), the length-weight relationships were deduced as follows: Log W = -4.35246 + 2.99158 Log L (r = 0.98799) 3.2. Sex distribution proportion On a monthly basis, the sex ratios of male and female individuals were calculated from a dataset of 5,675 fish with a total length (TL) exceeding 10 cm (individuals differentiated as male and female). The collective sex ratio was determined to be 1:1.3, implying a higher occurrence of females within the population. Throughout the duration of the study, female specimens consistently outweighed their male counterparts in the sample, except for the months of February and June, as depicted in Fig. 3 . 3.3. Attainment of sexual maturity Within every length category, the point of sexual maturity was ascertained for both males and females. The length at which 50% of males and females achieved sexual maturity was computed to be 15 cm and 15.5 cm in total length (TL), respectively. Notably, the most diminutive sexually mature male measured 11.4 cm, while the smallest sexually mature female measured 11.7 cm (Fig. 4 ). 3.4. Spawning Season and Gonado-Somatic Index (GSI) Mature fish with maturity stages V & VI were documented between September and December, with their highest concentration observed in October. Monthly fluctuations in the gonadosomatic index (GSI) by sex are illustrated in Fig. 5 . In both male and female specimens, the GSI exhibited a rising trend from May, maintaining elevated levels until October, followed by a gradual decline starting in November. Consequently, the period from September to December, with a zenith in October, was identified as the spawning season, indicating heightened spawning activity within this interval. 3.5. Fecundity Fecundity exhibited a positive correlation with increasing length and weight. The absolute fecundity spanned from 15,870 to 1,72,968 individuals. The average fecundity was determined to be 76,592 eggs. Mature to running phases ova ranging in size from 230 to 455 µm with a mode of 280–320 µm were observed. 4. Discussion The b value's mean (2.991) in the present investigation is closely approximated 3, signifying the species' isometric growth. Along the Kerala coast, an allometric coefficient (2.84) was documented for N. japonicus encompassing both sexes (Vinci and Nair 1974 ). The species has manifested both isometric and allometric growth dynamics during distinct temporal phases. Isometric growth patterns for N. japonicus were obtained from Madras (Vivekanandan and James 1986 ), Mumbai, Ratnagiri, Panaji (Pawar et al. 2011 ) and Veraval coast (Raje 2002 ; Manojkumar 2004 ). Allometric growth patterns have been reported from the Kakinada coast (Murty 1984 ), Veraval (Gopal and Vivekanandan 1991 ) and Mangaluru coast (Rajesh et al. 2011 ). Body shape exhibits a direct correlation with mass, a trait governed by ecological determinants including temperature, food accessibility, and reproductive circumstances, alongside additional variables like gender, age, fishing season, and fishing locale. In the current investigation, the sex ratio exhibited a marginal deviation from the anticipated 1:1 ratio, implying the prevalence of female specimens within commercial harvests. The comparable predominance of female individuals within trawl catches of N. japonicus has been documented by Acharya ( 1990 ) in the vicinity of the Bombay coast, Manojkumar ( 2004 ) off the Veraval coast, Rao et al. ( 2017 ) along the northeastern Indian coast, and Sarman et al. (2018) off the Saurashtra coastline. The findings of the present investigation revealed a male-biased precocity in sexual maturation. Approximately 50% of the male fish attained maturity at a length of 15 cm, while the corresponding length for females was slightly greater, at 15.5 cm. Krishnamoorthi ( 1971 ) documented the initial spawning length of N. japonicus off the Andhra-Orissa coast as 16–17 cm, with the second spawning occurring at around 22 cm. Notably, reports from the Veraval coast by Gopal and Vivekanandan ( 1991 ) as well as Manojkumar ( 2004 ) indicated sexual maturity lengths for N. japonicus ranging from 18 to 18.3 cm. Furthermore, Rajesh et al. ( 2013 ) reported the first sexual maturity length for males and females as 16.5 cm and 17.5 cm, respectively, in the context of the Mangaluru coast. According to CMFRI 2015, a study conducted between 2011 and 2013 found that the species matures at 14-14.5 cm off the coast of Chennai, Tamil Nadu. Rao et al. ( 2017 ) recorded the length at which females attained maturity as 15.1 cm along the northeastern coast of India. Conversely, Sarman et al. (2018) ascertained the length at initial sexual maturity for N. japonicus off the Saurashtra coast as 24 cm. Disparities in maturity length observed across distinct geographical areas are likely attributed to environmental factors. Consequently, it can be inferred that the biological traits of species within an ecosystem are subject to spatial and temporal variations. In the current investigation, the period of spawning activity encompassed the months from September to December, with the acme of Gonado-Somatic Index (GSI) values observed in October, signifying the zenith of the spawning season. Previous studies showed that the peak spawning period was between September and November off Visakhapatnam (Rajkumar et al. 2003 ). Manojkumar ( 2004 ) noted a spawning period spanning from October to February along the west coast of India. Kizhakudan et al. ( 2008 ) identified a spawning season spanning September to December off the Saurashtra coast and Rao et al. ( 2017 ) delineated a spawning season from August to February in the northern regions (Digha and Paradeep) and September to March in the southern regions (Visakhapatnam and Kakinada) of the northwestern coast. Sarman et al. (2018) documented the continuous year-round spawning of N. japonicus , with the apex of spawning activity occurring in December and January along the Saurashtra coast. Bakhsh ( 1994 ) deduced that the spawning behaviour of the threadfin bream exhibits regional divergence over extended timeframes, with influences such as wind patterns and ocean currents exerting a more direct effect on this behaviour as opposed to temperature. The investigation at hand revealed that N. japonicus had a fecundity range of 15,870 to 1,72,968 eggs, exhibiting an average of 76,592 eggs with ova diameters spanning from 230 to 455 µm. In diverse regions of India, studies examining N. japonicus fecundity have reported ranges of 10,260 to 1,84,946 eggs (Raje 2002 ), and 14,212 to 46,387 eggs (Manojkumar 2004 ) along the Veraval coast, as well as 10,472 to 65,225 eggs with a mean of 33,752 eggs off the Mangaluru coast (Rajesh et al. 2013 ), 13,176 to 1,30,798 eggs along the north-eastern coast (Rao et al. 2017 ), and a fecundity range of 14,806 to 1,65,032 eggs along the Saurashtra coast (Sarman et al. 2018). Notably, the fish size has been identified as the underlying determinant for the fecundity variation observed across distinct regions. 5. Conclusion The conducted investigation provided comprehensive insights into the reproductive biology of N. japonicus along the Northern Kerala coast (also known as the Malabar coast), marking the initial instance of such elucidation. Biological information is imperative to frame management measures in multispecies fisheries. The study signposted that N. japonicus matured significantly earlier (15-15.5 cm TL) compared to the last decade on the southwest coast. Shift in the spawning season to a lower temperature (Oct-Dec) months for better reproductive output is also evident for the climate change impact on tropical fishes. A similar observation was recorded along the east coast on the shift in the spawning peak of N. japonicus to cooler months in the recent decade. The outcome of the study aid to plan better management and conservation strategies for fishery resources. The study advocates the trawl fishing ban or effort reduction in such areas at peak spawning season and/or strongly recommends increasing the minimum legal size (MLS) to 16 cm for N. japonicus landings along the southwestern coast of India can benefit the sustainable harvest of the resource by a decrease in the recruitment overfishing. Declarations Acknowledgement: The authors extend their sincere appreciation to the Director of ICAR-CMFRI, Kochi, for unwavering support and encouragement throughout the duration of the study. Declaration of competing interest: The authors declare no conflicts of financial interest or personal affiliations that could be perceived to have influenced the research presented in this manuscript. Declaration of generative AI and AI-assisted technologies in the writing process: During the preparation of this work, the author(s) used ChatGPT to improve the readability. After using this tool/service, the author(s) reviewed and edited the content as needed and take(s) full responsibility for the content of the publication. Ethical Approval (applicable for both human and/ or animal studies): This declaration is “not applicable” to the study conducted since the sampling was done from commercial landings and the species do not belong to endangered and protected in the wild under the Indian Wildlife Protection Act. References Acharya P (1990) Studies on maturity, spawning and fecundity of Nemipterus japonicus (Bloch) off Bombay coast. J Ind Fish Ass 20: 51-57 Bagenal TB, Braum E, (1978) Eggs and early life history. In: Bagenal T (Ed) Methods of Assessment of Fish Production in Fresh Waters, IBP Handbook 3, Blackwell Scientific, Oxford, pp. 165-201 Bakhsh AA (1994) The Biology of Threadfin Bream, Nemipterus japonicus (Bloch) from the Jizan Region of the Red Sea. J King Abdulaziz Univ Mar Sci 7: 179-189 Barman RP, Mishra SS (2009) A Pictorial Guide to the Fishes of the family Nemipteridae of India. Zool Surv India, Kolkata Bloch M E (1791) Naturgeschichte der ausländischen Fische. 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Asokan","email":"","orcid":"","institution":"Calicut Regional Station, ICAR-Central Marine Fisheries Research Institute","correspondingAuthor":false,"prefix":"","firstName":"P.","middleName":"K.","lastName":"Asokan","suffix":""},{"id":319467010,"identity":"9178f2e6-8090-4ff2-aa14-5cab9785f13d","order_by":2,"name":"T. M. Najmudeen","email":"","orcid":"","institution":"ICAR-Central Marine Fisheries Research Institute","correspondingAuthor":false,"prefix":"","firstName":"T.","middleName":"M.","lastName":"Najmudeen","suffix":""},{"id":319467011,"identity":"71f8924a-40d0-4a75-8e4e-8a8cc7829832","order_by":3,"name":"K. Vinod","email":"","orcid":"","institution":"Calicut Regional Station, ICAR-Central Marine Fisheries Research Institute","correspondingAuthor":false,"prefix":"","firstName":"K.","middleName":"","lastName":"Vinod","suffix":""},{"id":319467012,"identity":"100865a3-0f08-4618-a5e8-294bca7dcc1e","order_by":4,"name":"N. R. Kalavathi","email":"","orcid":"","institution":"College of Fisheries, Mangaluru","correspondingAuthor":false,"prefix":"","firstName":"N.","middleName":"R.","lastName":"Kalavathi","suffix":""},{"id":319467014,"identity":"87347258-c591-46fd-a839-0b1929853f36","order_by":5,"name":"P. U. Zacharia","email":"","orcid":"","institution":"ICAR-Central Marine Fisheries Research Institute","correspondingAuthor":false,"prefix":"","firstName":"P.","middleName":"U.","lastName":"Zacharia","suffix":""},{"id":319467016,"identity":"7a87ca13-28f0-4cff-9b55-4dea03e4cd96","order_by":6,"name":"M. Vijisha","email":"","orcid":"","institution":"Calicut Regional Station, ICAR-Central Marine Fisheries Research Institute","correspondingAuthor":false,"prefix":"","firstName":"M.","middleName":"","lastName":"Vijisha","suffix":""},{"id":319467017,"identity":"16c0894c-eacd-4c15-b2a4-7d37bec90b6e","order_by":7,"name":"P. V. Gopalan","email":"","orcid":"","institution":"Calicut Regional Station, ICAR-Central Marine Fisheries Research Institute","correspondingAuthor":false,"prefix":"","firstName":"P.","middleName":"V.","lastName":"Gopalan","suffix":""}],"badges":[],"createdAt":"2024-06-07 08:38:51","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4544806/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4544806/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":59524671,"identity":"ab9c8967-630d-455f-9cad-11367b1711b7","added_by":"auto","created_at":"2024-07-02 20:48:21","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":66932,"visible":true,"origin":"","legend":"\u003cp\u003eMajor fishing harbours along the Malabar coast.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-4544806/v1/b756b77c13e86875cffea39a.png"},{"id":59525813,"identity":"e28117ac-8b39-4070-92e3-9e27ce9dfb03","added_by":"auto","created_at":"2024-07-02 20:56:21","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":30772,"visible":true,"origin":"","legend":"\u003cp\u003eRelationship between length and weight of \u003cem\u003eN. japonicus \u003c/em\u003e(sexes combined)\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-4544806/v1/214a7766211ba27267af878f.png"},{"id":59524672,"identity":"3775bf6e-39d6-4b52-8ab6-d593733bae1b","added_by":"auto","created_at":"2024-07-02 20:48:21","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":24840,"visible":true,"origin":"","legend":"\u003cp\u003eFluctuations in the monthly sex ratio of\u003cem\u003e N. japonicus\u003c/em\u003e\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-4544806/v1/247f8e92ba536c68e73804c5.png"},{"id":59525812,"identity":"948df24e-8d4a-4fee-b3e7-c3f4afc1fd78","added_by":"auto","created_at":"2024-07-02 20:56:21","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":60571,"visible":true,"origin":"","legend":"\u003cp\u003eAttainment of Maturity Length for\u003cem\u003e N. japonicus\u003c/em\u003e along the northern Kerala coast\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-4544806/v1/a1a184d3839f1a47746ad9a6.png"},{"id":59524675,"identity":"084ff5cc-e4a7-4088-a941-eacdc98d17e6","added_by":"auto","created_at":"2024-07-02 20:48:21","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":24140,"visible":true,"origin":"","legend":"\u003cp\u003eTemporal Changes in the Gonado-Somatic Index of \u003cem\u003eN. japonicus\u003c/em\u003e\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-4544806/v1/dc3bcaf67231e798d501bdca.png"},{"id":64071620,"identity":"7962c338-b400-41e9-82b2-1c007b5fc9a8","added_by":"auto","created_at":"2024-09-06 07:23:52","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":566419,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4544806/v1/1f03f789-612c-4366-b3a1-5608ecb385a2.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Does the fishing pressure induce fish to mature early? An evaluation of the reproductive biology of Nemipterus japonicus (Bloch, 1791) from the Malabar Coast of India","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003e \u003cem\u003eNemipterus japonicus\u003c/em\u003e, often called Japanese threadfin bream belongs to the Nemipteridae family and constitutes a vital component of the demersal fish catches caught primarily by bottom trawl fishing. Most \u003cem\u003eNemipterus\u003c/em\u003e species usually inhabit areas close to sandy or muddy seabeds, at depths ranging from 5 to 80 m (Russell \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e1993\u003c/span\u003e; Kerdgari et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). A total of ten species from the \u003cem\u003eNemipterus\u003c/em\u003e genus have been documented in the waters of India. (Barman and Mishra \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2009\u003c/span\u003e; Mahesh et al. \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), of which \u003cem\u003eN. randalli\u003c/em\u003e and \u003cem\u003eN. japonicus\u003c/em\u003e are the predominant species along the Kerala coast. The average catch of \u003cem\u003eNemipterus\u003c/em\u003e spp. in Kerala is 40,000 tonnes which contributed 37% to the demersal fish landings and 7% to the total fish landings of the state (NMFDC 2017\u0026ndash;2022). Due to its affordable price and meat quality, Japanese threadfin seabream ranks among the highly favoured and economically significant edible fish species, especially for surimi production.\u003c/p\u003e \u003cp\u003eRegulations are based on the reproductive characteristics of species subject to the greatest fishing pressure. Knowledge of reproductive parameters encompassing the length-weight correlation, sex ratio dynamics, reproductive periodicity patterns, and the peak spawning season is essential for determining the closure of the fishing season and minimum harvest sizes. Owing to their significant implications within the realm of fisheries, a plethora of investigations have been undertaken concerning the length-weight relationship, as evidenced by scholarly contributions such as those by Murty (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e1984\u003c/span\u003e); Bakhsh (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e1994\u003c/span\u003e); Zacharia (\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e1998\u003c/span\u003e); Rajkumar et al. (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2003\u003c/span\u003e); Manojkumar (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2004\u003c/span\u003e) and comprehensive investigations into diverse facets of nemipterid biology, with specific emphasis on \u003cem\u003eNemipterus japonicus\u003c/em\u003e, have been pursued. This scholarly exploration is evident in works by Kuthalingam (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1965\u003c/span\u003e); Krishnamoorthi (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e1971\u003c/span\u003e); Vinci (\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e1982\u003c/span\u003e); Murty (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e1984\u003c/span\u003e); Rao (\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e1989\u003c/span\u003e); Gopal and Vivekanandan (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e1991\u003c/span\u003e); Rajkumar et al. (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2003\u003c/span\u003e); Manojkumar (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2004\u003c/span\u003e); Kizhakudan et al. (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2008\u003c/span\u003e) along the Indian coast. A dearth of investigations on the length-weight relationship and reproductive biology of \u003cem\u003eNemipterus japonicus\u003c/em\u003e was observed along the Malabar coast. The current research endeavours to fill this gap by undertaking an evaluation of the length-weight relationship and reproductive biology of \u003cem\u003eNemipterus japonicus\u003c/em\u003e (Bloch \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1791\u003c/span\u003e) along the Malabar Coast, thereby facilitating an in-depth comprehension of the species' reproductive cycle.\u003c/p\u003e"},{"header":"2. Materials and methods","content":"\u003cp\u003eBetween 2017 and 2022, a total of 5,970 \u003cem\u003eNemipterus japonicus\u003c/em\u003e encompassing a spectrum of total lengths varying from 5.5 to 35 cm were meticulously acquired from the five prominent fishing harbours of Kasaragod, Kannur, Calicut, and Malappuram districts situated along the south-eastern periphery of the Arabian Sea (Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e). The specimens were collected every 10 days, landed from trawl boats, except in July, when mechanised fishing vessels are prohibited from operating. The specimens obtained were expeditiously preserved within insulated ice containers and transferred to the laboratory located at the Calicut Regional Station of the Central Marine Fisheries Research Institute, facilitating their subsequent in-depth examination and scholarly analysis.\u003c/p\u003e\n\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003e2.1. Length-weight allometry\u003c/h2\u003e\n \u003cp\u003eThe total length (TL) and body weight of all individual fish were meticulously measured with a precision of 1 mm and 0.1 g, respectively. The association between length and weight was quantified through the application of the formula denoted as W\u0026thinsp;=\u0026thinsp;a(L)\u003csup\u003eb\u003c/sup\u003e, where W signifies the total body weight in grams, L represents the total length in centimeters, \u0026apos;a\u0026apos; embodies the coefficient of body weight, and \u0026apos;b\u0026apos; denotes the exponent signifying allometric growth, as stipulated by Le Cren (\u003cspan class=\"CitationRef\"\u003e1951\u003c/span\u003e). To compare the correlation between the length and weight of both male and female specimens, an analysis of covariance (ANCOVA) methodology was employed, as detailed by Snedecor and Cochran (\u003cspan class=\"CitationRef\"\u003e1967\u003c/span\u003e).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\n \u003ch2\u003e2.2. Reproductive biology\u003c/h2\u003e\n \u003cp\u003eSex ratios were derived from monthly estimates of male and female numbers within the sample. The categorization of fish maturity phases hinged upon evaluating the spatial occupancy of the testes or ovaries and their macroscopic attributes. Employing the delineations outlined by the International Council for the Exploration of the Sea (ICES) in Lovern and Wood\u0026apos;s seminal work from 1937, the gonadal stages were delineated as immature, virgin developing/spent recovering, early maturing, late maturing, mature, running, and spent. Stage III onwards is considered as mature fish. The weight of gonads was measured to the nearest 0.01 g.\u003c/p\u003e\n \u003cp\u003eTo ascertain fecundity, the ovaries were conserved in customised Gilson\u0026apos;s fluid (Bagenal and Braum \u003cspan class=\"CitationRef\"\u003e1978\u003c/span\u003e). The fraction of mature fish in each length class was logistically fitted to calculate the length at first maturity (L\u003csub\u003em50\u003c/sub\u003e) (King \u003cspan class=\"CitationRef\"\u003e2007\u003c/span\u003e). The calculation of the gonadosomatic index (GSI) was conducted by factoring in both the weight of the gonads and the total weight of the fish, employing the subsequent formula: GSI = (GW/SW) * 100, wherein GW and SW correspond to the gonadal and somatic weights, respectively.\u003c/p\u003e\n \u003cp\u003eExcess moisture was removed from preserved ovaries and segments extracted from the anterior, middle, and posterior portions of ovaries exhibiting mature and running characteristics were employed as subsamples. Fecundity (F) was quantified through the application of the subsequent formula: F = [(Nss\u0026times;Wo) /Wss], wherein Nss symbolizes the oocyte count within the subsample, Wo denotes the overall weight of the ovary, and Wss represents the cumulative weight of the subsample.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003e3.1. Length-weight allometric relationship\u003c/h2\u003e \u003cp\u003eIn order to establish the length-weight allometric relationship, a dataset encompassing 5,970 fish specimens was employed, characterized by a range of total lengths (TL) spanning from 5.5 to 35.2 cm, and corresponding total weights (W) spanning from 2.2 to 498 g. All data were pooled and a common relationship was obtained for all sampled fishes including the undetermined sex specimens. Within this comprehensive dataset (illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e), the length-weight relationships were deduced as follows:\u003c/p\u003e \u003cp\u003eLog W = -4.35246\u0026thinsp;+\u0026thinsp;2.99158 Log L (r\u0026thinsp;=\u0026thinsp;0.98799)\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e3.2. Sex distribution proportion\u003c/h2\u003e \u003cp\u003eOn a monthly basis, the sex ratios of male and female individuals were calculated from a dataset of 5,675 fish with a total length (TL) exceeding 10 cm (individuals differentiated as male and female). The collective sex ratio was determined to be 1:1.3, implying a higher occurrence of females within the population. Throughout the duration of the study, female specimens consistently outweighed their male counterparts in the sample, except for the months of February and June, as depicted in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003e3.3. Attainment of sexual maturity\u003c/h2\u003e \u003cp\u003eWithin every length category, the point of sexual maturity was ascertained for both males and females. The length at which 50% of males and females achieved sexual maturity was computed to be 15 cm and 15.5 cm in total length (TL), respectively. Notably, the most diminutive sexually mature male measured 11.4 cm, while the smallest sexually mature female measured 11.7 cm (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.4. Spawning Season and Gonado-Somatic Index (GSI)\u003c/h2\u003e \u003cp\u003eMature fish with maturity stages V \u0026amp; VI were documented between September and December, with their highest concentration observed in October. Monthly fluctuations in the gonadosomatic index (GSI) by sex are illustrated in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e. In both male and female specimens, the GSI exhibited a rising trend from May, maintaining elevated levels until October, followed by a gradual decline starting in November. Consequently, the period from September to December, with a zenith in October, was identified as the spawning season, indicating heightened spawning activity within this interval.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.5. Fecundity\u003c/h2\u003e \u003cp\u003eFecundity exhibited a positive correlation with increasing length and weight. The absolute fecundity spanned from 15,870 to 1,72,968 individuals. The average fecundity was determined to be 76,592 eggs. Mature to running phases ova ranging in size from 230 to 455 \u0026micro;m with a mode of 280\u0026ndash;320 \u0026micro;m were observed.\u003c/p\u003e \u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eThe b value's mean (2.991) in the present investigation is closely approximated 3, signifying the species' isometric growth. Along the Kerala coast, an allometric coefficient (2.84) was documented for \u003cem\u003eN. japonicus\u003c/em\u003e encompassing both sexes (Vinci and Nair \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e1974\u003c/span\u003e). The species has manifested both isometric and allometric growth dynamics during distinct temporal phases. Isometric growth patterns for \u003cem\u003eN. japonicus\u003c/em\u003e were obtained from Madras (Vivekanandan and James \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e1986\u003c/span\u003e), Mumbai, Ratnagiri, Panaji (Pawar et al. \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2011\u003c/span\u003e) and Veraval coast (Raje \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2002\u003c/span\u003e; Manojkumar \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2004\u003c/span\u003e). Allometric growth patterns have been reported from the Kakinada coast (Murty \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e1984\u003c/span\u003e), Veraval (Gopal and Vivekanandan \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e1991\u003c/span\u003e) and Mangaluru coast (Rajesh et al. \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). Body shape exhibits a direct correlation with mass, a trait governed by ecological determinants including temperature, food accessibility, and reproductive circumstances, alongside additional variables like gender, age, fishing season, and fishing locale.\u003c/p\u003e \u003cp\u003eIn the current investigation, the sex ratio exhibited a marginal deviation from the anticipated 1:1 ratio, implying the prevalence of female specimens within commercial harvests. The comparable predominance of female individuals within trawl catches of \u003cem\u003eN. japonicus\u003c/em\u003e has been documented by Acharya (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1990\u003c/span\u003e) in the vicinity of the Bombay coast, Manojkumar (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2004\u003c/span\u003e) off the Veraval coast, Rao et al. (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2017\u003c/span\u003e) along the northeastern Indian coast, and Sarman et al. (2018) off the Saurashtra coastline.\u003c/p\u003e \u003cp\u003eThe findings of the present investigation revealed a male-biased precocity in sexual maturation. Approximately 50% of the male fish attained maturity at a length of 15 cm, while the corresponding length for females was slightly greater, at 15.5 cm. Krishnamoorthi (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e1971\u003c/span\u003e) documented the initial spawning length of \u003cem\u003eN. japonicus\u003c/em\u003e off the Andhra-Orissa coast as 16\u0026ndash;17 cm, with the second spawning occurring at around 22 cm. Notably, reports from the Veraval coast by Gopal and Vivekanandan (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e1991\u003c/span\u003e) as well as Manojkumar (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2004\u003c/span\u003e) indicated sexual maturity lengths for \u003cem\u003eN. japonicus\u003c/em\u003e ranging from 18 to 18.3 cm. Furthermore, Rajesh et al. (\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2013\u003c/span\u003e) reported the first sexual maturity length for males and females as 16.5 cm and 17.5 cm, respectively, in the context of the Mangaluru coast. According to CMFRI 2015, a study conducted between 2011 and 2013 found that the species matures at 14-14.5 cm off the coast of Chennai, Tamil Nadu. Rao et al. (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2017\u003c/span\u003e) recorded the length at which females attained maturity as 15.1 cm along the northeastern coast of India. Conversely, Sarman et al. (2018) ascertained the length at initial sexual maturity for \u003cem\u003eN. japonicus\u003c/em\u003e off the Saurashtra coast as 24 cm. Disparities in maturity length observed across distinct geographical areas are likely attributed to environmental factors. Consequently, it can be inferred that the biological traits of species within an ecosystem are subject to spatial and temporal variations.\u003c/p\u003e \u003cp\u003eIn the current investigation, the period of spawning activity encompassed the months from September to December, with the acme of Gonado-Somatic Index (GSI) values observed in October, signifying the zenith of the spawning season. Previous studies showed that the peak spawning period was between September and November off Visakhapatnam (Rajkumar et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2003\u003c/span\u003e). Manojkumar (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2004\u003c/span\u003e) noted a spawning period spanning from October to February along the west coast of India. Kizhakudan et al. (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2008\u003c/span\u003e) identified a spawning season spanning September to December off the Saurashtra coast and Rao et al. (\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2017\u003c/span\u003e) delineated a spawning season from August to February in the northern regions (Digha and Paradeep) and September to March in the southern regions (Visakhapatnam and Kakinada) of the northwestern coast. Sarman et al. (2018) documented the continuous year-round spawning of \u003cem\u003eN. japonicus\u003c/em\u003e, with the apex of spawning activity occurring in December and January along the Saurashtra coast. Bakhsh (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e1994\u003c/span\u003e) deduced that the spawning behaviour of the threadfin bream exhibits regional divergence over extended timeframes, with influences such as wind patterns and ocean currents exerting a more direct effect on this behaviour as opposed to temperature.\u003c/p\u003e \u003cp\u003eThe investigation at hand revealed that \u003cem\u003eN. japonicus\u003c/em\u003e had a fecundity range of 15,870 to 1,72,968 eggs, exhibiting an average of 76,592 eggs with ova diameters spanning from 230 to 455 \u0026micro;m. In diverse regions of India, studies examining \u003cem\u003eN. japonicus\u003c/em\u003e fecundity have reported ranges of 10,260 to 1,84,946 eggs (Raje \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2002\u003c/span\u003e), and 14,212 to 46,387 eggs (Manojkumar \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e2004\u003c/span\u003e) along the Veraval coast, as well as 10,472 to 65,225 eggs with a mean of 33,752 eggs off the Mangaluru coast (Rajesh et al. \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2013\u003c/span\u003e), 13,176 to 1,30,798 eggs along the north-eastern coast (Rao et al. \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2017\u003c/span\u003e), and a fecundity range of 14,806 to 1,65,032 eggs along the Saurashtra coast (Sarman et al. 2018). Notably, the fish size has been identified as the underlying determinant for the fecundity variation observed across distinct regions.\u003c/p\u003e"},{"header":"5. Conclusion","content":"\u003cp\u003eThe conducted investigation provided comprehensive insights into the reproductive biology of \u003cem\u003eN. japonicus\u003c/em\u003e along the Northern Kerala coast (also known as the Malabar coast), marking the initial instance of such elucidation. Biological information is imperative to frame management measures in multispecies fisheries. The study signposted that \u003cem\u003eN. japonicus\u003c/em\u003e matured significantly earlier (15-15.5 cm TL) compared to the last decade on the southwest coast. Shift in the spawning season to a lower temperature (Oct-Dec) months for better reproductive output is also evident for the climate change impact on tropical fishes. A similar observation was recorded along the east coast on the shift in the spawning peak of \u003cem\u003eN. japonicus\u003c/em\u003e to cooler months in the recent decade. The outcome of the study aid to plan better management and conservation strategies for fishery resources. The study advocates the trawl fishing ban or effort reduction in such areas at peak spawning season and/or strongly recommends increasing the minimum legal size (MLS) to 16 cm for \u003cem\u003eN. japonicus\u003c/em\u003e landings along the southwestern coast of India can benefit the sustainable harvest of the resource by a decrease in the recruitment overfishing.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgement:\u003c/strong\u003e The authors extend their sincere appreciation to the Director of ICAR-CMFRI, Kochi, for unwavering support and encouragement throughout the duration of the study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of competing interest:\u0026nbsp;\u003c/strong\u003eThe authors declare no conflicts of financial interest or personal affiliations that could be perceived to have influenced the research presented in this manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of generative AI and AI-assisted technologies in the writing process:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDuring the preparation of this work, the author(s) used ChatGPT to improve the readability. After using this tool/service, the author(s) reviewed and edited the content as needed and take(s) full responsibility for the content of the publication.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eEthical Approval (applicable for both human and/ or animal studies):\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis declaration is \u0026ldquo;not applicable\u0026rdquo; to the study conducted since the sampling was done from commercial landings and the species do not belong to endangered and protected in the wild under the Indian Wildlife Protection Act.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAcharya P (1990) Studies on maturity, spawning and fecundity of Nemipterus japonicus (Bloch) off Bombay coast. J Ind Fish Ass 20: 51-57\u003c/li\u003e\n\u003cli\u003eBagenal TB, Braum E, (1978) Eggs and early life history. 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Indian J Fish 45(3): 265-270\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"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":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Nemipterus japonicus, Length-weight, Early maturity, Spawning cycle, Minimum legal size","lastPublishedDoi":"10.21203/rs.3.rs-4544806/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4544806/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn fisheries management, a comprehensive comprehension of the reproductive biology of fish species is imperative, with specific emphasis on factors such as sexual maturation, the dynamics of the reproductive cycle, and the quantitative assessment of fecundity. To elucidate the reproductive dynamics of \u003cem\u003eNemipterus japonicus\u003c/em\u003e captured along the Malabar coast, encompassing parameters such as the sex ratio, sexual maturation, fecundity, and reproductive periodicity, a rigorous investigation was conducted spanning the period from 2017 to 2021. Sampled individuals of \u003cem\u003eN. japonicus\u003c/em\u003e exhibited total lengths ranging from 5.5 to 35.2 cm. The exponent value (b\u0026thinsp;=\u0026thinsp;2.991) observed in this current study exhibited a high degree of proximity to 3, indicative of an isometric growth pattern. The collective sex ratio stood at 1:1.3, signifying a higher prevalence of females than males. Attainment of 50% sexual maturation (L\u003csub\u003em50\u003c/sub\u003e) occurred at a total length of 15 cm for males and 15.5 cm for females which is earlier than the reported length. Monthly changes in the gonadosomatic index exhibited elevated values from September to December, reaching their zenith in October. The study ascertained \u003cem\u003eN. japonicus\u003c/em\u003e matured significantly earlier than in the last decade and the spawning season shifted to lower temperature months for better reproductive output along the south-west coast of India.\u003c/p\u003e","manuscriptTitle":"Does the fishing pressure induce fish to mature early? An evaluation of the reproductive biology of Nemipterus japonicus (Bloch, 1791) from the Malabar Coast of India","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-02 20:48:16","doi":"10.21203/rs.3.rs-4544806/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"f0a65b88-c12d-40f7-befd-dba57c881326","owner":[],"postedDate":"July 2nd, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-09-06T07:15:45+00:00","versionOfRecord":[],"versionCreatedAt":"2024-07-02 20:48:16","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4544806","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4544806","identity":"rs-4544806","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}