The potential influence of habitat composition on seasonal lobster movements and their distribution in the Great Bay Estuary, New Hampshire

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Watson III, Raymond E. Grizzle This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3844217/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 24 Oct, 2024 Read the published version in Estuaries and Coasts → Version 1 posted 5 You are reading this latest preprint version Abstract Although estuaries create many physiological challenges for lobsters ( Homarus americanus ), there may also be some advantages for lobsters residing in these unique systems. While some lobsters in the Great Bay Estuary (GBE) make seasonal migrations into and out of the GBE, many remain year-round, including ovigerous (egg-bearing) females. Furthermore, lobsters that are resident in the GBE tend to aggregate in specific areas. The overall goal of this study was to determine why lobsters (both ovigerous and non-ovigerous) tend to spend more time in certain areas of the GBE. Specifically, we set out to test the hypothesis for two disparate areas of GBE that have features potentially making them conducive habitats for long-term lobster residency. We used a combination of habitat mapping using underwater videography and diver surveys to compare areas where lobsters aggregated compared with those areas where lobster density was known to be low. Areas where lobsters spent the most time in GBE were similar to coastal marine habitats, comprised mostly of rocky (hardbottom) complexes interspersed with macroalgae. In contrast, areas with the fewest lobsters were primarily comprised of sandy, soft sediment. The strong relationship between complex, rocky habitats and lobster residency in GBE suggest that habitat quality in other estuaries might have a strong impact on the distribution, abundance, and residency of lobsters and increases the likelihood that some estuaries may support year-round resident lobster populations. Estuaries Homarus americanus lobster movements video analyses complex estuarine habitats Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction The American lobster ( Homarus americanus ) supports one of the most important and successful fisheries in the Gulf of Maine (LeBris et al. 2018; ASMFC 2020; ACCSP 2023). While most lobsters are harvested from coastal and offshore locales, lobsters are also found in a number of shallow bays and estuaries, including the Great Bay Estuary (herein, GBE) in New Hampshire (Thomas 1968 ; Munro and Therriault 1983 ; Able et al. 1988 ; Wahle 1993 ; Watson et al. 1999 ; Jones 2000 ; Short et al. 2001 ; Moore et al. 2020 ). Over the past couple of decades, commercial lobster harvesting in GBE has generated over 100,000 pounds of lobsters at a value more than $ 500,000 (NHFG 2008; 2009). While estuarine habitats often present physiologically-challenging conditions for lobsters, due to both dramatic decreases in salinity as a result of spring freshwater runoff and episodic storm events (Jury et al. 1994a ; b ), and very warm summer temperatures, estuaries also provide advantages to lobsters, including accelerated growth (i.e., molting, due to warmer temperatures), refugia from predation, or for use as nursery habitats (Munro and Therriault 1983 ; Lawton and Lavalli 1995 ; Moriysu et al. 1999; Short et al. 2001 ; Tang et al. 2015 ). To maximize the benefits of estuaries and reduce their exposure to stressful and potentially lethal conditions, lobsters use their sensory capabilities to detect and respond to both temperature and salinity to guide their movements so they can avoid unfavorable conditions (Crossin et al. 1998 ; Nielsen and McGaw 2016; Jury et al. 2019 ; Pauly et al. 2022 ) Both laboratory- and field-based studies suggest that lobsters can detect small changes in both temperature and salinity and will behaviorally thermoregulate by avoiding temperatures that are too low, or too high, and move when salinities drop below 12 psu as well as waters that are too warm (Vetrovs 1990 ; Jury et al. 1994a ; Jury et al. 1995 ; Crossin et al. 1998 ; Jury and Watson 2000 ; Dufort et al. 2001 ). These behavioral traits appear to drive seasonal movements in lobsters that are most dramatic in the fall and spring (Watson et al. 1999 ; Goldstein and Watson 2015 ; Moore et al. 2020 ). In the spring, when water temperatures exceed 12°C, lobsters in GBE tend to move up-estuary, toward the warmest areas (Silver and Brown 1975 ; Watson et al. 1999 ; Jury et al. 2018 ). As temperatures in the upper reaches of GBE exceed 22°C in summer, lobsters tend to move short distances down-estuary, toward slightly cooler waters (Jury et al. 2018 ). Finally, by fall, as the estuary cools faster than the coast, lobsters tend to move toward the coast (Watson et al. 1999 ; Langley 2017 ). While the seasonal movements of some lobsters out of the estuary toward coastal waters ensues, a large proportion of adult lobsters remain year-round within the GBE, including berried (i.e., egg-bearing or ovigerous) females. Moore et al. ( 2020 ) demonstrated that these resident females carry their eggs over the winter and spring months, and hatch in the summer after a 9-11month incubation period. This was confirmed with data derived from neuston tows documenting that lobster larvae (Stages I-IV) are present in the water column a month before these lobsters appear in coastal waters, which is consistent with the stages of the eggs carried by berried females captured in Great Bay vs coastal waters (NHFG 2009; Moore et al. 2020 ). These data, taken together, suggest that lobster larvae are released and disburse in the GBE and that some proportion of the population is derived from resident lobster reproduction. Data from previous studies of lobster movements in the GBE indicate that lobsters tend to prefer some areas over others (Howell et al. 1999 ; Watson et al. 1999 ; Langley et al. 2017; Jury et al. 2018 ; Moore et al. 2020 ). In one of the first studies of lobster movements in the GBE, Watson et al. ( 1999 ) used both tag-recapture and acoustic telemetry approaches to document the movements of lobsters throughout the entire estuary, over the course of a year. Lobsters that moved the most were those tagged and released furthest up in the GBE (see Fig. 1 ), while those further down-estuary tended to move the least. In a more recent study by Moore et al. ( 2020 ) ovigerous lobsters (n = 9) were tagged in in the fall in Little Bay (Fig. 1 ), and they remained in that area until the following spring when their eggs likely hatched. These data were further substantiated by sea sampling data that also revealed a high density of ovigerous lobsters that Little Bay, in comparison with other parts of the GBE. Thus, our working hypothesis for this study was that there are benthic habitat features in this area that make it attractive to lobsters. To our knowledge there have been few studies that use benthic habitat analyses to help better understand the distribution and movements of mobile decapod crustaceans, such as lobsters. In one such study, Stone and O’Clair ( 2002 ) used ultrasonic telemetry to track female Dungeness crabs ( Cancer magister ) over the course of a season in an Alaskan estuary and related then explained their seasonal movements in terms of habitat use. These authors concluded that female crabs utilized benthic sediments for brooding their eggs over the winter and then moved into more shallow rocky habitats in the spring, where dissolved oxygen levels were higher, to release their larvae. Likewise, Geraldi et al. ( 2009 ) used a combination of geo-referenced lobster-trap arrays and side-scan sonar data to demonstrate that lobsters showed fewer movements and higher site fidelity in areas of rocky habitat, compared with soft-sediment habitats which, in turn, affected their density and catch in a particular area. The major goal of this study was to further test the hypothesis that the movements of lobsters in a northern New England estuary are influenced by the benthic habitat they are exposed to which, in turn, increases their propensity to reside there. In this study we conducted dive surveys and benthic video surveys at two disparate areas within the GBE system to determine if the movements and distribution of lobsters reported in previous studies (Langley et al. 2017; Moore et al. 2020 ) were correlated with specific habitat types. Methods Study site GBE is a large, tidally mixed basin that comprises 23 km 2 of surface water and over 160 km of coastline and is linked to the ocean through the Piscataqua River estuarine complex in New Hampshire and Maine (Reichard and Ceilikko 1978; Brown and Arellano 1979 ; Jones 2000 ; Fig. 1 ). Both Great Bay (GB) and Little Bay (LB) possess habitats that are generally characterized by extensive mud flats and oyster farms, and sparse eelgrass ( Zostera marina ) beds (Short 1992 ; Grizzle pers. obs.). Seasonal trends in water temperatures and salinities are well characterized in GBE (15–30 psu, 2–24°C; Fig. 1 in Jury et al. ( 1995 ); Fig. 2 in Howell et al. ( 1999 ); Fig. 1 in Watson et al. ( 1999 ); Fig. 3 in Fulton et al. ( 2013 ), and Fig. 2 and Fig. S1 in Moore et al. 2020 ), with a gradient of decreasing salinity and increasing temperatures from the coast to areas further up into the estuary. It should also be noted that in a typical year salinities average > 20 psu during most months, except in April when salinities often decrease to 15–19 psu due to the spring runoff from spring ice melt. Underwater video mapping Underwater video mapping was conducted in the fall of 2009 at four selected areas within the Little Bay-Piscataqua River complex (Fig. 1 ). These areas were chosen because they overlapped with the locations where lobsters were tagged and tracked using ultrasonic telemetry in 2007–2009 (see Langley 2017 ; Moore et al. 2020 ). Specifically, these areas consisted of sections of benthic habitats around the peripheries of Goat Island (GI) (north and south), Fox Point (FP), and Little Bay (LB), within a depth range of 3–15 m (average = 6.5 m, details in Fig. 1 ). Underwater video mapping was conducted using a custom-made underwater videography system consisting of a Sea-Drop 650 underwater color camera with 45 m of cable mounted on a custom stainless-steel sled (see Grizzle et al. 2008 for details). Video was viewed live with an onboard LCD screen and recorded to a hard-drive using a SEA-DVR mini digital video recorder and a SEA-TRAK™ GPS video overlay, which was selected for later spatial analysis using ArcGIS v. 9.3 (ESRI Corp. Redlands, CA). All video components were purchased and customized from an underwater video specialty manufacturer (SeaViewer Inc., Tampa, FL). The benthic camera-sled system was typically deployed with a steel cable on a manually operated winch from a small research vessel. After positioning the camera at a height suitable for obtaining adequate image quality and swath width (typically about 0.5 m above the bottom), the unit was slowly towed (∼ 1.5 knots) alongside the vessel so that it remained approximately directly below the winch. Video images were viewed in real-time to allow for quick adjustments of the camera throughout the survey. For purposes of this study, continuous video imagery was designed around a sampling grid that was acquired from 3–5 parallel transects across each study area, and an additional set of 3–5 transects set perpendicular in our four study locations. A total of 40–55 minutes of video imagery were recorded for each location. Video and habitat analysis All digital videos were uploaded from a hard-drive to a Mac-minicomputer (Apple Inc., Cupertino, CA). Still digital images from the video recordings were captured at 30-second intervals using QuickTime Pro v.7.0 (Apple, Inc.) and saved as individual JPEG files. A total of 50–75 representative images were saved for each site. All still images were then imported into a random-point count software program (Coral Point Count with Excel extensions, CPCe v. 3.6, see: http://www.nova.edu/ocean/cpce/ ) that assigns points to prominent bottom habitat features (e.g., rubble, algae, sand, rock, etc.) so their composition can be quantified (see Kohler and Gill 2006 for details). CPCe uses a matrix of randomly distributed points overlaid on digital images to quantify the proportion of substrate types and then it statistically compiles these values to estimate the proportion of biota present. For this analysis, a stratified random design (5 rows, 5 columns, and 1 point per cell) was chosen, with a total of 25 points for each image. Preset habitat features were customized to six categories, representative of local benthic habitats (verified by SCUBA surveys in the same survey areas) and included: cobble, rubble, boulder, sand, macroalgae, and other (e.g., soft sediment). Habitat features were classified according to methods and descriptions in both Wahle and Steneck ( 1991 ) and Wahle ( 1993 ). CPCe analysis gives the average % cover (± sem) for each image as well as ascribing a Shannon-Weiner diversity index based on comparisons of each of the six habitat types defined for each image. A Shannon-Weiner index ( H ), in this case, takes into account the proportion of each habitat (evenness) and the amount of each habitat feature (richness) represented by the following function: H = - \({\sum }_{\varvec{i}=1}^{\varvec{S}}{\varvec{p}}_{\varvec{i}}\mathbf{l}\mathbf{n}\left({\varvec{p}}_{\varvec{i}}\right)\) Where H is the diversity index, s is the number of species, and p i is the proportion of individuals of the total sample belonging to the i th species (Smith and Smith 2001 ). Data compiled by the CPCe algorithm from each of the four sites were pooled into two sites demarcated by Fox Point (FP): 1) Goat Island and down-estuary of FP; and 2) FP and up-estuary to Little Bay (Fig. 1 ). Overall differences between sites were analyzed as a two-factor nested ANOVA (model I) using SPSS v. 18.0 (SPSS Inc., Chicago, Illinois). A generalized linear model (GLM, univariate) was fit for 2 factors: location (2 levels), and habitat types (6 levels) with the dependent variable, percent cover. Raw data were arc-sin transformed to meet the parametric assumptions of homogeneity of variance and normality. Differences among habitat features in the interaction term (location*habitat type) were assessed using a series of post-hoc Tukey’s HSD tests at an α = 0.05. Differences in diversity indices ( H ) were tested using a one-way ANOVA between each of the two sites. All graphical output is represented as the mean ± sem. Diver surveys For each of our video-surveyed areas, two SCUBA surveys were conducted with the goal of: 1) confirming and comparing major habitat types seen by the video analysis; and 2) estimating the abundance of lobsters. For the first goal, two divers surveyed a 2 m swath along 25 m transects placed out from a center point in each of the four cardinal compass directions. Habitat types (previously described) were quantified as percent cover calculated as a proportion of each habitat along the transect. For the second goal, divers conducted 30-minute visual surveys in each of the four areas to count all lobsters encountered. Coverages for each habitat type were compared to similar data from the video surveys using a series of one-way ANOVA analyses at an α = 0.05. Results Overall, a total of 97 images were extracted and analyzed from videos at site-1 (GI - FP down-estuary) and 91 images from site-2 (LB – FP upstream). In general, the habitat composition was different between the two locations (Fig. 2 ). The LB site was characterized by large bare areas of sand and mud, interspersed with small patches of cobble and boulders. In contrast, the bottom around GI was rocky with complex macroalgal patches and some sandy areas (Fig. 3 ). Habitat analysis and diversity indices The total percentage cover of all habitat types indicated a mix of cobble, boulder, and sand from Fox Point to Goat Island, compared to more sand, some cobble and few rocks from Fox Point up-estuary into Little Bay (Table 1 ). Pooled data between GI and FP (downriver) and LB and FP (upriver), indicated a significant difference between sites with respect to habitat coverage ( F = 49.04; df = 5, 304; p = 0.001; 1- β = 1.00) and the interaction of location with habitat ( F = 4.720; df = 5, 304; p = 0.001; 1- β = 0.98) (Table 2 ). Post-hoc comparisons of each of the 6 habitat types examined showed that three (boulder, sand, and macroalgae), were markedly different in overall percent cover at GI compared to LB (Tukey’s HSD, p = 0.001; Fig. 4 ). Average sand and macroalgal coverages in LB were 74.4 and 14.1%, respectively, compared with 11.5 and 23.6% for GI (Fig. 5 ). Table 1 Averages (± sem) for total %-coverage between areas that were mapped using videography. Also see Fig. 4 for images and spatial references to each specific location examined Location : Goat Island Fox Point (downriver) Fox Point (upriver) Little Bay Habitat : cobble 38.63 ± 6.63 62.35 ± 6.24 49.17 ± 6.81 30.25 ± 7.33 rubble 5.38 ± 1.98 3.53 ± 1.44 1.08 ± 0.57 7.00 ± 2.44 boulder 8.63 ± 3.07 18.59 ± 4.66 1.17 ± 1.01 4.5 ± 2.43 macroalgae 15.5 ± 2.86 6.24 ± 2.82 3.42 ± 1.08 8.5 ± 2.02 sand 30.38 ± 5.78 8.12 ± 3.91 42.92 ± 6.11 49.63 ± 7.17 other 1.5 ± 0.67 1.18 ± 0.52 2.25 ± 0.75 0.13 ± 0.13 Total 100.00 100.00 100.00 100.00 Table 2 ANOVA summary table for the analysis of habitat type differences between the up-estuary area between Fox Point a portion of Little Bay and down-estuary from Fox Point to the area around Goat Island Source of variation df MS F p 1-β location 1 0.570 3.83 0.051 0.50 habitat type 5 7.311 49.04 0.001 1.00 location*habitat type 5 0.704 4.72 0.001 0.98 within Groups (Error) 304 0.149 Total 315 8.734 Overall, Shannon-Weiner indices ( H ) were higher and significantly different at GI ( H AVG = 0.75 ± 0.041, n = 55) compared with LB ( H AVG = 0.56 ± 0.49, n = 51) (1-way ANOVA; F = 8.312; df = 1, 102; p = 0.005), indicating a more diverse and even habitat composition around GI than in LB. Diver surveys SCUBA surveys at both study areas verified that the habitat videos captured during the underwater video surveys were representative of the six habitat types that could be quantified by divers (one-way ANOVAs, p > 0.05; Fig. 5 ). A total of 22 lobsters were counted at LB dive sites compared with 53 lobsters at GI. Discussion Elements of habitat quality and associated spatial patterns in an area can appreciably shape the distribution, movements, and population structure of local marine species, including large mobile decapod crustaceans (Pitman and McAlpine 2003; Nathan 2008 ; Chang et al. 2010 ; Florko et al. 2021 ). The impetus for this study was to determine if differences in habitat composition were related to where lobsters are known to reside in GBE as well as those areas where lobsters are in comparably lower numbers, and we used habitat as a proxy for examining this hypothesis. Although larger scale bathymetry and general habitat features of the GBE have been mapped (NOAA-NCEI 2018; CCOM-JHC 2022), this study was aimed at quantifying and describing habitat features that were associated with known areas of lobster residency at a more detailed biological resolution (i.e., microhabitat) through a combination of video and dive surveys. Overall, our findings suggest that habitat composition was markedly different between areas on the up-estuary, south side of Fox Point, in LB, and the region slightly down-estuary, northeast of Fox Point, near GI, where lobsters are known to reside and often overwinter (Langley 2017 ; Moore et al. 2020 ). Habitats in the vicinity of GI were more complex than in LB, and best described as ‘ocean-like’; with patches of kelp interspersed with cobble and boulder fields (Becker 1994 ; Grizzle 2005 ). Mathieson et al. ( 1981 ; 1983 ) described a variety of flora associated with these habitats including subtidal kelp ( Laminaria digitata ) beds (i.e., estuarine tidal rapids) that are more typical of coastal nearshore areas than estuaries. Although the areas in LB south of FP contained some patches of cobble, especially closer to FP, most of the region that was surveyed was made up-estuary of extensive sand and mud flats. Becker ( 1994 ) conducted a more extensive SCUBA survey of habitat composition in LB and an adjacent cove just downstream of our GI survey site and she found a measurable difference in bottom cover between the two sites. Becker ( 1994 ) also quantified over 15 types of bottom cover, including six types of cobble and boulder size compositions, and reported that > 80% of the coverage in the lower reaches of GBE were composed of cobble-boulder complexes, compared with 80% soft-sediment coverage upstream of FP. It was somewhat surprising that cobble habitat was not statistically different between the two sites examined in the current study, but this may be due to the size of the areas examined, which were much smaller in our study than those surveyed by Becker, and the criteria used to identify cobble features. What is generally termed ‘rocky habitat’ (i.e., boulder and cobble) was analyzed as separate categories for our study (Table 1 ), but sometimes they are combined. For example, Selgrath et al. ( 2007 ) defines cobble as “a mixture of unconsolidated pebbles, cobbles, and boulders, 1-400 cm”. When we carried out an additional ANOVA analysis between our two study sites, in which we combined cobble and boulder into one type of cover, we found a significant difference (one-way ANOVA, p = 0.018); with a total coverage of 66% and 48% for GI and FP, respectively. Use of complex habitats by lobsters It was not surprising that we found an order of magnitude more lobsters in the complex habitats around GI, than up-estuary in LB. The affinity of lobsters for complex habitats has been documented in many other cases (e.g., Karnofsky 1989; Chang et al. 2010 ) and Becker ( 1994 ) in our study area. Becker also reported that > 50% of all lobsters found in dive surveys downstream of FP were between 40–60 mm carapace length (CL), including a number of very small, newly recruited, lobsters (10–30 mm CL). Complex habitats such as cobble, boulder, and algal beds provide shelter and foraging for juvenile lobsters (Wahle and Steneck 1991 ; see Lawton and Lavalli 1995 , for review) and some studies suggest a positive correlation between complex habitats and the presence of a variety of sizes of lobsters (Acosta 1999 ; Selgrath et al. 2007 ; Young et al. 2016 ). Often referred to as microhabitat features, such areas can support a variety of flora and fauna, which influence the distribution of organisms in particular areas (Saunders et al. 1991 ). The higher diversity index ( H) in habitat coverage at GI compared with LB is consistent with diver observations and video images of the complex habitats in the area around GI. Lobster movements and their distribution in Little Bay While it has been well documented that some lobsters from the coast and the connecting Piscataqua River transit up into the GBE during the summer months, and some lobsters do the reverse in the fall (Watson et al. 1999 ), it remains unclear how many lobsters reside year around in the GBE. In 2007, over 30 lobsters (70–90 mm CL) were tagged at GI and, although some moved a short distance (~ 0.5 km) toward the coast, most remained near their original tagging location for a full season (Langley 2017 ). By comparison, lobsters tagged and released in 2008 in LB showed a net movement toward GI, suggesting the habitat near GI is more favorable than in LB. Subsequently, Moore et al. ( 2020 ) used acoustic telemetry to track a total of nine ovigerous females captured near GI in October and they all remained in that area throughout the winter and into the spring, when their eggs likely hatched. While there are few, if any, reports of year-round resident adult lobster populations in estuarine systems (e.g., Wahle 1993 ), our results appear to suggest that some proportion of lobsters in the GBE reside there year-round and contribute new recruits as well, helping to further the connectivity and ecological importance of estuarine coastal habitats for some lobster populations. Furthermore, our data reinforce the possibility that a proportion of adult lobsters in GBE prefer complex habitats surrounding GI, especially while they overwinter. Although environmental cues and conditions (e.g., temperature, salinity) are likely to affect lobster movements and the habitat suitability of certain regions of the GBE (Watson et al. 1999 ; Goldstein and Watson 2015 ; Jury et al. 2018 ; Moore et al. 2020 ), appropriate bottom features (e.g., hardbottom, kelp beds, cobble) may also influence lobster residency. For example, Geraldi et al. ( 2009 ) found that lobsters caught in rocky, complex substrates moved far less than those captured and released in soft sediment habitats. Specifically, 82% of lobsters caught on rocky substrate were again caught in the same habitat. Furthermore, this study suggested that some areas of sediment between bedrock outcroppings or deep channels may serve as habitat corridors for short- or long-term movements of lobsters seeking sheltering habitats (Geraldi et al. 2009 ). Additionally, both Estrella and Morrissey ( 1997 ) and Watson et al. ( 1999 ) found that lobsters were more likely to move (and did so rapidly) when presented with suboptimal habitats on outer Cape Cod and in Great Bay Estuary, respectively. Clearly, more work is needed to better determine the relationship between habitat bottom type, marine landscape, and movements of lobsters (both transient and resident) as a key consideration for continued and improved lobster management. Impact of habitat on lobster movements The present study expands upon previous studies of lobster movements and reproduction in the GBE (references herein) and demonstrates that lobsters in the GBE tend to concentrate and reside in regions of preferred habitat, such as in the vicinity of GI, where the benthic conditions resemble those along the NH (southern Gulf of Maine) coastline. Thus, locations such as these provide direct benefits to local lobster populations and the fishery. For example, Rowe ( 2002 ) found that no-take reserves in Bonavista Bay, Newfoundland in suitable lobster habitat increased lobster density, most likely by offering a high density of shelters for egg-producing females. Similarly, Selgrath et al. ( 2007 ) reported that patchy environments (particularly edges), that included cobble and seagrass, were integral to the survival and distribution of lobsters over a range of sizes. Similar fragmented and insular habitats (such as estuaries) are also known to hold significant refuge value, serve as movement conduits, and influence predator-prey dynamics for a variety of crustaceans including lobsters (Acosta 1999 ; Micheli and Peterson 1999 ; Hovel and Lipcius 2001 ; Grabowski et al. 2008 ; Hovel and Wahle 2010 ; Yeager and Hovel 2017 ). There are several reasons why complex estuarine habitats, such as those around GI likely benefit lobsters in the GBE. First, they provide safe habitats for ovigerous females because of the abundance of suitable shelters. Second, conditions during the winter tend to be relatively calmer (i.e., less impact from storms), compared with most areas along the coast. Goldstein and Watson ( 2015 ) found that lobsters along the New Hampshire coast (mouth of the Piscataqua River) tended to move offshore in the fall, as storms became severe enough to cause considerable turbulence. Third, in the spring, the GBE exhibits a much faster rate of temperature increase in the spring compared with coastal waters, so, as documented by Moore et al. ( 2020 ) larvae hatch sooner and gain an accelerated start on their planktonic development phase. And finally, the larvae that hatch here might also be retained and settle in a more suitable habitat for their development. Previous research has shown that ocean surface drifters released around FP and GI tended to be retained locally over a period of 2–3 weeks (Goldstein 2012 ; Moore et al. 2020 ), so at least a share of larvae released in this area might settle in the cobble fields and macroalgal beds that are preferred by early benthic phase lobsters (Wahle and Steneck 1991 ; 1992 ). As such, the present study strongly suggests that these areas could be considered essential lobster nursery habitat (Dahlgren et al. 2006 ), at least for estuarine lobsters. Declarations Funding Support for this project was provided by the UNH Graduate School Summer Fellowship Program, the Great Bay Steward’s Foundation, as well as a NOAA-NERR Graduate Research Fellowship to JSG. Acknowledgements We are grateful to Dave Shay, Krystin Ward, and Kate Masury for their help and support in the field. We thank Jacob Aman at Wells NERR for his GIS expertise with Fig. 1. 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Geraldi, N. R., R. A. Wahle, and M. Dunnington. 2009. Habitat effects on American lobster ( Homarus americanus ) movement and density: insights from georeferenced trap arrays, seabed mapping, and tagging. Canadian Journal of Fisheries and Aquatic Sciences 66: 460–470. Goldstein, J. S. 2012. The impact of seasonal movements by ovigerous American lobsters ( Homarus americanus ) on egg development and larval release. Doctoral Dissertations, 648. 1–332. https://scholars.unh.edu/dissertation/648 . Goldstein, J. S., and W. H. Watson. 2015. Quantifying the influence of natural inshore and offshore thermal regimes on egg development in the North American lobster, Homarus americanus. Biological Bulletin 228: 1–12. Grabowski, J. H., A. R. Hughes, and D. L. Kimbro. 2008. Habitat complexity influences cascading effects of multiple predators. Ecology 89: 3413–3422. Grizzle, R. E. 2005. Spaulding Turnpike Environmental Impact Study . 14p ed. UNH Jackson Estuarine Laboratory. Grizzle, R. E., M. A. Brodeur, H. A. Abeels, and J. K. Greene. 2008. Bottom habitat mapping using towed underwater videography: Subtidal oyster reefs as an example application. Journal of Coastal Research 24: 103–109. Hovel, K. A., and R. A. Wahle. 2010. Effects of habitat patchiness on American lobster movement across a gradient of predation risk and shelter competition. Ecology 91: 1993–2002. Hovel, K. A., and R. N. Lipcius. 2001. Habitat fragmentation in a seagrass landscape: Patch size and complexity control blue crab survival. Ecology 82: 1814–1829. Howell, W. H., W. H. Watson III, and S. H. Jury. 1999. Skewed sex ratio in an estuarine lobster ( Homarus americanus ) population. Journal of Shellfish Research 18: 193–201. Jones, S. H. 2000. A technical characterization of estuarine and coastal New Hampshire. New Hampshire Estuaries Project. PREP Publications. 280 p. http://scholars.unh.edu/prep/294 . Jury, S. H., and W. H. Watson III. 2000. Thermosensitivity of the American lobster, Homarus americanus . 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The effects of reduced salinity on lobster ( Homarus americanus Milne Edwards) metabolism: implications for estuarine populations. Journal of Experimental Marine Biology and Ecology 176: 167–185. Karnofsky, E. B., J. Atema, and R. H. Elgin. 1989. Field observations of social behavior, shelter use, and foraging in the lobster, Homarus americanus . Biological Bulletin 176: 239–246. Kohler, K. E., and S. M. Gill. 2006. Coral Point Count with Excel extensions (CPCe): A Visual Basic program for the determination of coral and substrate coverage using random point count methodology. Computers and Geosciences 32: 1259–1269. Langley, T. G. 2017. Seasonal movements and activity levels of American lobsters ( Homarus americanus ) in an estuary. MS thesis. University of New Hampshire. 71 p. Lawton, P., and K. L. Lavalli. 1995. Postlarval, juvenile, adolescent, and adult ecology. In Biology of the lobster Homarus americanus , ed. J. R. Factor. 47–81. San Diego: Academic Press. Le Bris, A., K. E. Mills, R. A. Wahle, Y. Chen, and M. A. Alexander. J.A., Andrew. Schuetz, J. G., and J. D. Scott. 2018. Climate vulnerability and resilience in the most valuable North American fishery. Proceedings of the National Academy of. Sciences 115: 1831–1836. Mathieson, A. C., C. D. Neefus, and E. Penniman. 1983. Benthic ecology in an estuarine tidal rapid. Botanic Marina 26: 213–230. Mathieson, A. C., N. B. Reynolds, and E. J. Hehre. 1981. Investigations of New England marine algae II. The species composition, distribution, and zonation of seaweeds in Great Bay Estuary system and the adjacent open coast of New Hampshire. Botanic Marina 24: 533–545. Micheli, F., and C. H. Peterson. 1999. Estuarine vegetated habitats as corridors for predator movements. Conservation Biology 869–881. Moore, E. M., T. G. Langley, J. S. Goldstein, and W. H. Watson III. 2020. American lobster, Homarus americanus , reproduction and recruitment in a New England Estuary. Estuaries and Coasts . 10.1007/s12237-020-00759-4 . Moriyasu, M., W. Landsburg, E. Wade, and D. R. Maynard. 1999. The role of an estuary environment for regeneration of claws in the American lobster, Homarus americanus H. Milne Edwards, 1837 (Decapoda). Crustaceana 72: 415–433. Munro, J., and J. C. Therriault. 1983. Migrations saisonnieres du homard ( Homarus americanus ) entre la cote et les lagunes des Ilesde-la-Madeleine. Canadian Journal of Fisheries and Aquatic Sciences 40: 905–918. Nathan, R. 2008. An emerging movement ecology paradigm. Proceedings of the National Academy of Sciences 105: 19050–19051. New Hampshire Fish and Game (NHFG). 2009. Online marine resources. . Accessed 15 December 2022. New Hampshire Fish and Game (NHFG). 2008. Monitoring of the American lobster ( Homarus americanus ) resource and fishery in New Hampshire. 20p. Nielson, T. V., and I. J. McGaw. 2016. Behavioral thermoregulation and trade-offs in juvenile lobster Homarus americanus . Biological Bulletin 230: 35–50. NOAA National. 2022. Centers for Environmental Information (NOAA-NCEI). https:// data.noaa.gov/metaview/page?xml=NOAA/NESDIS/NGDC/MGG/DEM//iso/xml/great_bay_n130_30m.xml &view=getDataView&header=none# Pittman, S. J., and C. A. McAlpine. 2003. Movements of marine fish and decapod crustaceans: process, theory, and application. Advances in Marine Biology 44: 205–294. Pauly, D., U. S. Amarasinghe, E. Chu, K. Meirelles Felizola Freire, E. Vázquez, and M. J. Butler IV. 2022. The growth, respiration, and reproduction of crustaceans: a synthesis through the Gill-Oxygen Limitation Theory (GOLT). Journal of Crustacean Biology 42: 1–13. Reichard, R., and B. Celikkol. 1978. Hydrodynamic model of the Great Bay Estuary System, Part I. In Sea Grant Tech. Report. UNH-SG-153 , 108. Durham: Sea Grant Program, University of New Hampshire. Rowe, S. 2002. Population parameters of American lobster inside and outside no-take reserves in Bonavista Bay, Newfoundland. Fisheries Research 56: 167–175. Saunders, D. A., R. J. Hobbs, and C. R. Margules. 1991. Biological consequences of ecosystem fragmentation: a review. Conservation Biology 5: 18–32. Selgrath, J. C., K. A. Hovel, and R. A. Wahle. 2007. Effects of habitat edges on American lobster abundance and survival. Journal of Experimental Marine Biology and Ecology 353: 253–264. Short, F. T. 1992. The ecology of the Great Bay estuary, New Hampshire and Maine: an . estuarine profile and bibliography . National Oceanic and Atmospheric Administration, Silver Spring, MD. 222 p. Short, F. T., K. Matso, H. M. Hoven, J. Whitten, D. M. Burdick, and C. A. Short. 2001. Lobster use of eelgrass habitat in the Piscataqua River on the New Hampshire/Maine Border, USA. Estuaries 24: 277–284. Silver, A. L., and W. S. Brown. 1975. Great Bay Estuarine Field Program 1975 Data Report – Part 2: Temperature, Salinity and Density. UNH Sea Grant Technical Report. UNH-SG-163. 65 p. Smith, R. L., and T. M. Smith. 2001. Community Structure. In Ecology and Field Biology , San Francisco: Benjamin Cummings. Stone, R. P., and C. E. O’Clair. 2002. Behavior of female Dungeness crabs, Cancer magister , in a glacial southeast Alaska estuary: Homing, brooding-site fidelity, seasonal movements, and habitat use. Journal of Crustacean Biology 22: 481–492. Tang, F., T. Minch, K. Dinning, C. J. Martyniuk, R. Kilada, and R. Rochette. 2015. Size at age and body condition of juvenile American lobsters ( Homarus americanus ) living on cobble and mud in a mixed–bottom embayment in the Bay of Fundy. Marine Biology 162: 69–79. Thomas, M. L. H. 1968. Overwintering of American lobsters, Homarus americanus , in burrows in Bideford River, Prince Edward Island. Journal of Fisheries Research Board of Canada 25: 2725–2727. Vetrovs, A. 1990. The distribution of lobsters ( Homarus americanus ) in the Great Bay Estuary. MS thesis, University of New Hampshire, Durham. Wahle, R. A. 1993. Recruitment to American lobster populations along an estuarine gradient. Estuaries 16: 731–738. Wahle, R. A., and R. S. Steneck. 1992. Habitat restrictions in early benthic life: experiments on habitat selection and in situ predation with the American lobster. Journal of Experimental Marine Biology and Ecology 157: 91–114. Wahle, R. A., and R. S. Steneck. 1991. Recruitment habitats and nursery grounds of American lobster ( Homarus americanus Milne Edwards): A demographic bottleneck? Marine Ecology Progress Series 69: 231–243. Watson, I. I. I., W.H., A. Vetrovs, and W. H. Howell. 1999. Lobster movements in an estuary. Marine Biology 134: 65–75. Yeager, M. E., and K. A. Hovel. 2017. Structural complexity and fish body size interactively affect habitat optimality. Oecologia 185: 257–267. Young, M. A., D. Ierodiaconou, M. Edmunds, M. Hulands, and A. C. G. Schimel. 2016. Accounting for habitat and seafloor structure characteristics on southern rock lobster ( Jasus edwardsii ) assessment in a small marine reserve. Marine Biology . 10.1007/s00227-016-2914-y . Cite Share Download PDF Status: Published Journal Publication published 24 Oct, 2024 Read the published version in Estuaries and Coasts → Version 1 posted Reviewers agreed at journal 13 Feb, 2024 Reviewers invited by journal 29 Jan, 2024 Editor invited by journal 09 Jan, 2024 Editor assigned by journal 07 Jan, 2024 First submitted to journal 07 Jan, 2024 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. 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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-3844217","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":270174968,"identity":"3c9c1824-7573-4674-a45c-b88a8cc2de6a","order_by":0,"name":"Jason Seth Goldstein","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA/UlEQVRIiWNgGAWjYBACxgYg8YANSDAzMD74AKTZ2InRksDGIAHUwmw4A6SFmRirwFqAiqV5GMDW4QfM/ccvPkgoq6vjZ+c9IG3za5s8H9CFHz7m4HHYjJxig4RzhyUkm/kSjHP7bhu2AV0oOXMbPi08aRKJbQckDA7zGCTn9txmBGphY+bFp6X/DEhLnYQ9UMthy57b9oS1NKQfA2phljBg5jFsZvhxO5Gwlhk5zCC/SM44zGPM2NtwO7mNmbEZr18M+48/fPChrI6fv/+M+Y8ff27bzm9vPvjhIz4tDTwGSHa2QRyLWz0QyDOwP0Di/sGreBSMglEwCkYoAAAUQ03eFqzFhgAAAABJRU5ErkJggg==","orcid":"","institution":"Wells National Estuarine Research Reserve","correspondingAuthor":true,"prefix":"","firstName":"Jason","middleName":"Seth","lastName":"Goldstein","suffix":""},{"id":270174969,"identity":"4083a01f-463f-4298-a9da-ac091e87cd4c","order_by":1,"name":"Winsor H. Watson III","email":"","orcid":"","institution":"University of New Hampshire","correspondingAuthor":false,"prefix":"","firstName":"Winsor","middleName":"H. Watson","lastName":"III","suffix":""},{"id":270174970,"identity":"c18e2c1c-bc48-429d-b344-4bfa6b79cffc","order_by":2,"name":"Raymond E. Grizzle","email":"","orcid":"","institution":"University of New Hampshire","correspondingAuthor":false,"prefix":"","firstName":"Raymond","middleName":"E.","lastName":"Grizzle","suffix":""}],"badges":[],"createdAt":"2024-01-08 01:54:58","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3844217/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3844217/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s12237-024-01445-5","type":"published","date":"2024-10-24T15:57:03+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":50521943,"identity":"a6b437bf-0dc5-4067-91cf-21cd5775a8ef","added_by":"auto","created_at":"2024-02-01 19:14:30","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":4975749,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eA) \u003c/strong\u003eLocation of the Great Bay Estuary (GBE), New Hampshire (NH) within the context of the southern Gulf of Maine;\u003cstrong\u003e B) \u003c/strong\u003eStudy area within the GBE complex including Little Bay (primary site for lobster tagging and surveys) as well as the Piscataqua River, leading to Portsmouth, NH and seacoast; \u003cstrong\u003eC)\u003c/strong\u003e Little Bay study area with bathymetric depth contours where lobsters were tagged and tracked at two separate sites (triangle symbols) in 2007 and in 2008 for Little Bay and Goat Island, respectively (see details in Moore et al. 2020). Bathymetric data set derived from hydrographic survey soundings (data source: noaa.gov.ngdc.mgg.dem_great_bay_n130_30m; Great Bay NH [N130] bathymetric digital elevation model [30 m resolution]). Imagery service from Maxar Technologies and Earthstar Geographics (2023)\u003c/p\u003e","description":"","filename":"FIG1.png","url":"https://assets-eu.researchsquare.com/files/rs-3844217/v1/5edc11668e58926954a1e893.png"},{"id":50521940,"identity":"7c90d84f-21fb-4960-adfa-c426db1afddb","added_by":"auto","created_at":"2024-02-01 19:14:30","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1116420,"visible":true,"origin":"","legend":"\u003cp\u003eA comparison of typical bottom habitat between \u003cstrong\u003eA)\u003c/strong\u003e Little Bay (LB) and \u003cstrong\u003eB)\u003c/strong\u003e Goat Island (GI) within GBE. Both images were taken as still frame JPEGs from videos. Note the sand-dominated habitat at the LB site compared with rocky benthic habitat features at GI (depth ranges for both sites were 5-12 m). Similar images were imported into the CPCe software and the areas below the yellow vertical reference lines were analyzed. GPS overlays for all video (and images) provided geo-referencing for mapping areas covered using ArcGIS v. 9.3\u003c/p\u003e","description":"","filename":"F2.png","url":"https://assets-eu.researchsquare.com/files/rs-3844217/v1/cdf65335eeba9b6d7ad2ad34.png"},{"id":50521944,"identity":"27f20f5b-ed0e-4997-80c0-a6bda8a55070","added_by":"auto","created_at":"2024-02-01 19:14:30","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":17822803,"visible":true,"origin":"","legend":"\u003cp\u003eA photomontage of habitat composition between the two general study sites in the GBE: 1) Little Bay and upriver of Fox Point (blue and yellow dots; area = 256,947 m\u003csup\u003e2\u003c/sup\u003e, depth: 3-12 m) and; 2) Goat Island and downriver of Fox Point (green and red dots; area = 177,465 m\u003csup\u003e2\u003c/sup\u003e. Depth: 5-15 m). Digital images are representative of habitat features for each area and averaged from a compilation of still images extracted from video (details in methods). Points for each location were georeferenced to images and mapped using ArcGIS v. 9.3\u003c/p\u003e","description":"","filename":"FIG3.png","url":"https://assets-eu.researchsquare.com/files/rs-3844217/v1/14df627eb4540fc7ba703000.png"},{"id":50521941,"identity":"59fc69fe-0e85-4f7e-990d-3d9336c48348","added_by":"auto","created_at":"2024-02-01 19:14:30","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":175284,"visible":true,"origin":"","legend":"\u003cp\u003eMean coverage of the benthos for six different habitat types near Goat Island and Little Bay (pooled with Fox Pt data from either up-estuary or down-estuary). Habitat types were compiled from images derived from video surveys at each location and analyzed with a random-point count software package (CPCe). Data are presented as means ± sem. Different letters denote a significant difference between habitat types in the two locations (ANOVA, p \u0026lt; 0.05)\u003c/p\u003e","description":"","filename":"FIG4.png","url":"https://assets-eu.researchsquare.com/files/rs-3844217/v1/45062327813e7c8234029af8.png"},{"id":50521942,"identity":"33c3b1a9-df72-4700-ad89-bfe8e6599a84","added_by":"auto","created_at":"2024-02-01 19:14:30","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":144721,"visible":true,"origin":"","legend":"\u003cp\u003eA comparison of the habitat coverage at the Goat Island and Little Bay studies sites, as measured by SCUBA and video analyses. Data are presented as means ± sem. There were no significant differences between any of the habitat types between both methodologies that were used (ANOVA, p \u0026gt; 0.05)\u003c/p\u003e","description":"","filename":"FIG5.png","url":"https://assets-eu.researchsquare.com/files/rs-3844217/v1/85cc232de07b1ce946d6e675.png"},{"id":67682487,"identity":"ff019c0c-0a6c-4901-a277-576057443f54","added_by":"auto","created_at":"2024-10-28 16:14:32","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":41754783,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3844217/v1/4d7ca659-3ead-4972-a211-532b46a429ac.pdf"}],"financialInterests":"","formattedTitle":"The potential influence of habitat composition on seasonal lobster movements and their distribution in the Great Bay Estuary, New Hampshire","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe American lobster (\u003cem\u003eHomarus americanus\u003c/em\u003e) supports one of the most important and successful fisheries in the Gulf of Maine (LeBris et al. 2018; ASMFC 2020; ACCSP 2023). While most lobsters are harvested from coastal and offshore locales, lobsters are also found in a number of shallow bays and estuaries, including the Great Bay Estuary (herein, GBE) in New Hampshire (Thomas \u003cspan citationid=\"CR69\" class=\"CitationRef\"\u003e1968\u003c/span\u003e; Munro and Therriault \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e1983\u003c/span\u003e; Able et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e1988\u003c/span\u003e; Wahle \u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e1993\u003c/span\u003e; Watson et al. \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e1999\u003c/span\u003e; Jones \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2000\u003c/span\u003e; Short et al. \u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Moore et al. \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Over the past couple of decades, commercial lobster harvesting in GBE has generated over 100,000 pounds of lobsters at a value more than \u003cspan\u003e$\u003c/span\u003e500,000 (NHFG 2008; 2009). While estuarine habitats often present physiologically-challenging conditions for lobsters, due to both dramatic decreases in salinity as a result of spring freshwater runoff and episodic storm events (Jury et al. \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e1994a\u003c/span\u003e;\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003eb\u003c/span\u003e), and very warm summer temperatures, estuaries also provide advantages to lobsters, including accelerated growth (i.e., molting, due to warmer temperatures), refugia from predation, or for use as nursery habitats (Munro and Therriault \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e1983\u003c/span\u003e; Lawton and Lavalli \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e1995\u003c/span\u003e; Moriysu et al. 1999; Short et al. \u003cspan citationid=\"CR64\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Tang et al. \u003cspan citationid=\"CR68\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). To maximize the benefits of estuaries and reduce their exposure to stressful and potentially lethal conditions, lobsters use their sensory capabilities to detect and respond to both temperature and salinity to guide their movements so they can avoid unfavorable conditions (Crossin et al. \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1998\u003c/span\u003e; Nielsen and McGaw 2016; Jury et al. \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Pauly et al. \u003cspan citationid=\"CR57\" class=\"CitationRef\"\u003e2022\u003c/span\u003e)\u003c/p\u003e \u003cp\u003eBoth laboratory- and field-based studies suggest that lobsters can detect small changes in both temperature and salinity and will behaviorally thermoregulate by avoiding temperatures that are too low, or too high, and move when salinities drop below 12 psu as well as waters that are too warm (Vetrovs \u003cspan citationid=\"CR70\" class=\"CitationRef\"\u003e1990\u003c/span\u003e; Jury et al. \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e1994a\u003c/span\u003e; Jury et al. \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e1995\u003c/span\u003e; Crossin et al. \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e1998\u003c/span\u003e; Jury and Watson \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e2000\u003c/span\u003e; Dufort et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2001\u003c/span\u003e). These behavioral traits appear to drive seasonal movements in lobsters that are most dramatic in the fall and spring (Watson et al. \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e1999\u003c/span\u003e; Goldstein and Watson \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Moore et al. \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). In the spring, when water temperatures exceed 12\u0026deg;C, lobsters in GBE tend to move up-estuary, toward the warmest areas (Silver and Brown \u003cspan citationid=\"CR65\" class=\"CitationRef\"\u003e1975\u003c/span\u003e; Watson et al. \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e1999\u003c/span\u003e; Jury et al. \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). As temperatures in the upper reaches of GBE exceed 22\u0026deg;C in summer, lobsters tend to move short distances down-estuary, toward slightly cooler waters (Jury et al. \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Finally, by fall, as the estuary cools faster than the coast, lobsters tend to move toward the coast (Watson et al. \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e1999\u003c/span\u003e; Langley \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2017\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eWhile the seasonal movements of some lobsters out of the estuary toward coastal waters ensues, a large proportion of adult lobsters remain year-round within the GBE, including berried (i.e., egg-bearing or ovigerous) females. Moore et al. (\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) demonstrated that these resident females carry their eggs over the winter and spring months, and hatch in the summer after a 9-11month incubation period. This was confirmed with data derived from neuston tows documenting that lobster larvae (Stages I-IV) are present in the water column a month before these lobsters appear in coastal waters, which is consistent with the stages of the eggs carried by berried females captured in Great Bay vs coastal waters (NHFG 2009; Moore et al. \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). These data, taken together, suggest that lobster larvae are released and disburse in the GBE and that some proportion of the population is derived from resident lobster reproduction. Data from previous studies of lobster movements in the GBE indicate that lobsters tend to prefer some areas over others (Howell et al. \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e1999\u003c/span\u003e; Watson et al. \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e1999\u003c/span\u003e; Langley et al. 2017; Jury et al. \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Moore et al. \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). In one of the first studies of lobster movements in the GBE, Watson et al. (\u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e1999\u003c/span\u003e) used both tag-recapture and acoustic telemetry approaches to document the movements of lobsters throughout the entire estuary, over the course of a year. Lobsters that moved the most were those tagged and released furthest up in the GBE (see Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), while those further down-estuary tended to move the least. In a more recent study by Moore et al. (\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) ovigerous lobsters (n\u0026thinsp;=\u0026thinsp;9) were tagged in in the fall in Little Bay (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), and they remained in that area until the following spring when their eggs likely hatched. These data were further substantiated by sea sampling data that also revealed a high density of ovigerous lobsters that Little Bay, in comparison with other parts of the GBE. Thus, our working hypothesis for this study was that there are benthic habitat features in this area that make it attractive to lobsters.\u003c/p\u003e \u003cp\u003eTo our knowledge there have been few studies that use benthic habitat analyses to help better understand the distribution and movements of mobile decapod crustaceans, such as lobsters. In one such study, Stone and O\u0026rsquo;Clair (\u003cspan citationid=\"CR67\" class=\"CitationRef\"\u003e2002\u003c/span\u003e) used ultrasonic telemetry to track female Dungeness crabs (\u003cem\u003eCancer magister\u003c/em\u003e) over the course of a season in an Alaskan estuary and related then explained their seasonal movements in terms of habitat use. These authors concluded that female crabs utilized benthic sediments for brooding their eggs over the winter and then moved into more shallow rocky habitats in the spring, where dissolved oxygen levels were higher, to release their larvae. Likewise, Geraldi et al. (\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2009\u003c/span\u003e) used a combination of geo-referenced lobster-trap arrays and side-scan sonar data to demonstrate that lobsters showed fewer movements and higher site fidelity in areas of rocky habitat, compared with soft-sediment habitats which, in turn, affected their density and catch in a particular area.\u003c/p\u003e \u003cp\u003eThe major goal of this study was to further test the hypothesis that the movements of lobsters in a northern New England estuary are influenced by the benthic habitat they are exposed to which, in turn, increases their propensity to reside there. In this study we conducted dive surveys and benthic video surveys at two disparate areas within the GBE system to determine if the movements and distribution of lobsters reported in previous studies (Langley et al. 2017; Moore et al. \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) were correlated with specific habitat types.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy site\u003c/h2\u003e \u003cp\u003eGBE is a large, tidally mixed basin that comprises 23 km\u003csup\u003e2\u003c/sup\u003e of surface water and over 160 km of coastline and is linked to the ocean through the Piscataqua River estuarine complex in New Hampshire and Maine (Reichard and Ceilikko 1978; Brown and Arellano \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e1979\u003c/span\u003e; Jones \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2000\u003c/span\u003e; Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Both Great Bay (GB) and Little Bay (LB) possess habitats that are generally characterized by extensive mud flats and oyster farms, and sparse eelgrass (\u003cem\u003eZostera marina\u003c/em\u003e) beds (Short \u003cspan citationid=\"CR62\" class=\"CitationRef\"\u003e1992\u003c/span\u003e; Grizzle pers. obs.). Seasonal trends in water temperatures and salinities are well characterized in GBE (15\u0026ndash;30 psu, 2\u0026ndash;24\u0026deg;C; Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e in Jury et al. (\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e1995\u003c/span\u003e); Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e in Howell et al. (\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e1999\u003c/span\u003e); Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e in Watson et al. (\u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e1999\u003c/span\u003e); Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e in Fulton et al. (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2013\u003c/span\u003e), and Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e and Fig. S1 in Moore et al. \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2020\u003c/span\u003e), with a gradient of decreasing salinity and increasing temperatures from the coast to areas further up into the estuary. It should also be noted that in a typical year salinities average\u0026thinsp;\u0026gt;\u0026thinsp;20 psu during most months, except in April when salinities often decrease to 15\u0026ndash;19 psu due to the spring runoff from spring ice melt.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eUnderwater video mapping\u003c/h2\u003e \u003cp\u003eUnderwater video mapping was conducted in the fall of 2009 at four selected areas within the Little Bay-Piscataqua River complex (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). These areas were chosen because they overlapped with the locations where lobsters were tagged and tracked using ultrasonic telemetry in 2007\u0026ndash;2009 (see Langley \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Moore et al. \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Specifically, these areas consisted of sections of benthic habitats around the peripheries of Goat Island (GI) (north and south), Fox Point (FP), and Little Bay (LB), within a depth range of 3\u0026ndash;15 m (average\u0026thinsp;=\u0026thinsp;6.5 m, details in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eUnderwater video mapping was conducted using a custom-made underwater videography system consisting of a Sea-Drop 650 underwater color camera with 45 m of cable mounted on a custom stainless-steel sled (see Grizzle et al. \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e2008\u003c/span\u003e for details). Video was viewed live with an onboard LCD screen and recorded to a hard-drive using a SEA-DVR mini digital video recorder and a SEA-TRAK\u0026trade; GPS video overlay, which was selected for later spatial analysis using ArcGIS v. 9.3 (ESRI Corp. Redlands, CA). All video components were purchased and customized from an underwater video specialty manufacturer (SeaViewer Inc., Tampa, FL). The benthic camera-sled system was typically deployed with a steel cable on a manually operated winch from a small research vessel. After positioning the camera at a height suitable for obtaining adequate image quality and swath width (typically about 0.5 m above the bottom), the unit was slowly towed (\u0026sim; 1.5 knots) alongside the vessel so that it remained approximately directly below the winch. Video images were viewed in real-time to allow for quick adjustments of the camera throughout the survey. For purposes of this study, continuous video imagery was designed around a sampling grid that was acquired from 3\u0026ndash;5 parallel transects across each study area, and an additional set of 3\u0026ndash;5 transects set perpendicular in our four study locations. A total of 40\u0026ndash;55 minutes of video imagery were recorded for each location.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eVideo and habitat analysis\u003c/h2\u003e \u003cp\u003eAll digital videos were uploaded from a hard-drive to a Mac-minicomputer (Apple Inc., Cupertino, CA). Still digital images from the video recordings were captured at 30-second intervals using QuickTime Pro v.7.0 (Apple, Inc.) and saved as individual JPEG files. A total of 50\u0026ndash;75 representative images were saved for each site. All still images were then imported into a random-point count software program (Coral Point Count with Excel extensions, CPCe v. 3.6, see: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttp://www.nova.edu/ocean/cpce/\u003c/span\u003e\u003cspan address=\"http://www.nova.edu/ocean/cpce/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e) that assigns points to prominent bottom habitat features (e.g., rubble, algae, sand, rock, etc.) so their composition can be quantified (see Kohler and Gill \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2006\u003c/span\u003e for details). CPCe uses a matrix of randomly distributed points overlaid on digital images to quantify the proportion of substrate types and then it statistically compiles these values to estimate the proportion of biota present. For this analysis, a stratified random design (5 rows, 5 columns, and 1 point per cell) was chosen, with a total of 25 points for each image. Preset habitat features were customized to six categories, representative of local benthic habitats (verified by SCUBA surveys in the same survey areas) and included: cobble, rubble, boulder, sand, macroalgae, and other (e.g., soft sediment). Habitat features were classified according to methods and descriptions in both Wahle and Steneck (\u003cspan citationid=\"CR73\" class=\"CitationRef\"\u003e1991\u003c/span\u003e) and Wahle (\u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e1993\u003c/span\u003e). CPCe analysis gives the average % cover (\u0026plusmn; sem) for each image as well as ascribing a Shannon-Weiner diversity index based on comparisons of each of the six habitat types defined for each image. A Shannon-Weiner index (\u003cem\u003eH\u003c/em\u003e), in this case, takes into account the proportion of each habitat (evenness) and the amount of each habitat feature (richness) represented by the following function:\u003c/p\u003e \u003cp\u003e \u003cem\u003eH\u003c/em\u003e = -\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\({\\sum }_{\\varvec{i}=1}^{\\varvec{S}}{\\varvec{p}}_{\\varvec{i}}\\mathbf{l}\\mathbf{n}\\left({\\varvec{p}}_{\\varvec{i}}\\right)\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003cp\u003eWhere \u003cem\u003eH\u003c/em\u003e is the diversity index, \u003cem\u003es\u003c/em\u003e is the number of species, and \u003cem\u003ep\u003c/em\u003e\u003csub\u003e\u003cem\u003ei\u003c/em\u003e\u003c/sub\u003e is the proportion of individuals of the total sample belonging to the \u003cem\u003ei\u003c/em\u003e\u003csup\u003e\u003cem\u003eth\u003c/em\u003e\u003c/sup\u003e species (Smith and Smith \u003cspan citationid=\"CR66\" class=\"CitationRef\"\u003e2001\u003c/span\u003e). Data compiled by the CPCe algorithm from each of the four sites were pooled into two sites demarcated by Fox Point (FP): 1) Goat Island and down-estuary of FP; and 2) FP and up-estuary to Little Bay (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Overall differences between sites were analyzed as a two-factor nested ANOVA (model I) using SPSS v. 18.0 (SPSS Inc., Chicago, Illinois). A generalized linear model (GLM, univariate) was fit for 2 factors: location (2 levels), and habitat types (6 levels) with the dependent variable, percent cover. Raw data were arc-sin transformed to meet the parametric assumptions of homogeneity of variance and normality. Differences among habitat features in the interaction term (location*habitat type) were assessed using a series of post-hoc Tukey\u0026rsquo;s HSD tests at an α\u0026thinsp;=\u0026thinsp;0.05. Differences in diversity indices (\u003cem\u003eH\u003c/em\u003e) were tested using a one-way ANOVA between each of the two sites. All graphical output is represented as the mean \u0026plusmn; sem.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eDiver surveys\u003c/h2\u003e \u003cp\u003eFor each of our video-surveyed areas, two SCUBA surveys were conducted with the goal of: 1) confirming and comparing major habitat types seen by the video analysis; and 2) estimating the abundance of lobsters. For the first goal, two divers surveyed a 2 m swath along 25 m transects placed out from a center point in each of the four cardinal compass directions. Habitat types (previously described) were quantified as percent cover calculated as a proportion of each habitat along the transect. For the second goal, divers conducted 30-minute visual surveys in each of the four areas to count all lobsters encountered. Coverages for each habitat type were compared to similar data from the video surveys using a series of one-way ANOVA analyses at an α\u0026thinsp;=\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eOverall, a total of 97 images were extracted and analyzed from videos at site-1 (GI - FP down-estuary) and 91 images from site-2 (LB \u0026ndash; FP upstream). In general, the habitat composition was different between the two locations (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The LB site was characterized by large bare areas of sand and mud, interspersed with small patches of cobble and boulders. In contrast, the bottom around GI was rocky with complex macroalgal patches and some sandy areas (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eHabitat analysis and diversity indices\u003c/h2\u003e \u003cp\u003eThe total percentage cover of all habitat types indicated a mix of cobble, boulder, and sand from Fox Point to Goat Island, compared to more sand, some cobble and few rocks from Fox Point up-estuary into Little Bay (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Pooled data between GI and FP (downriver) and LB and FP (upriver), indicated a significant difference between sites with respect to habitat coverage (\u003cem\u003eF\u003c/em\u003e\u0026thinsp;=\u0026thinsp;49.04; \u003cem\u003edf\u003c/em\u003e\u0026thinsp;=\u0026thinsp;5, 304; \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001; 1-\u003cem\u003eβ\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1.00) and the interaction of location with habitat (\u003cem\u003eF\u003c/em\u003e\u0026thinsp;=\u0026thinsp;4.720; \u003cem\u003edf\u003c/em\u003e\u0026thinsp;=\u0026thinsp;5, 304; \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001; 1-\u003cem\u003eβ\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.98) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Post-hoc comparisons of each of the 6 habitat types examined showed that three (boulder, sand, and macroalgae), were markedly different in overall percent cover at GI compared to LB (Tukey\u0026rsquo;s HSD, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.001; Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Average sand and macroalgal coverages in LB were 74.4 and 14.1%, respectively, compared with 11.5 and 23.6% for GI (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAverages (\u0026plusmn; sem) for total %-coverage between areas that were mapped using videography. Also see Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e for images and spatial references to each specific location examined\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eLocation\u003c/em\u003e:\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGoat Island\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFox Point (downriver)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFox Point (upriver)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eLittle Bay\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eHabitat\u003c/em\u003e:\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ecobble\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e38.63\u0026thinsp;\u0026plusmn;\u0026thinsp;6.63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e62.35\u0026thinsp;\u0026plusmn;\u0026thinsp;6.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e49.17\u0026thinsp;\u0026plusmn;\u0026thinsp;6.81\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e30.25\u0026thinsp;\u0026plusmn;\u0026thinsp;7.33\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003erubble\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.38\u0026thinsp;\u0026plusmn;\u0026thinsp;1.98\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.53\u0026thinsp;\u0026plusmn;\u0026thinsp;1.44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e7.00\u0026thinsp;\u0026plusmn;\u0026thinsp;2.44\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eboulder\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8.63\u0026thinsp;\u0026plusmn;\u0026thinsp;3.07\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18.59\u0026thinsp;\u0026plusmn;\u0026thinsp;4.66\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.17\u0026thinsp;\u0026plusmn;\u0026thinsp;1.01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.5\u0026thinsp;\u0026plusmn;\u0026thinsp;2.43\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003emacroalgae\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15.5\u0026thinsp;\u0026plusmn;\u0026thinsp;2.86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.24\u0026thinsp;\u0026plusmn;\u0026thinsp;2.82\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.42\u0026thinsp;\u0026plusmn;\u0026thinsp;1.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8.5\u0026thinsp;\u0026plusmn;\u0026thinsp;2.02\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003esand\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30.38\u0026thinsp;\u0026plusmn;\u0026thinsp;5.78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8.12\u0026thinsp;\u0026plusmn;\u0026thinsp;3.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e42.92\u0026thinsp;\u0026plusmn;\u0026thinsp;6.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e49.63\u0026thinsp;\u0026plusmn;\u0026thinsp;7.17\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eother\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.5\u0026thinsp;\u0026plusmn;\u0026thinsp;0.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.18\u0026thinsp;\u0026plusmn;\u0026thinsp;0.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.25\u0026thinsp;\u0026plusmn;\u0026thinsp;0.75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.13\u0026thinsp;\u0026plusmn;\u0026thinsp;0.13\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e100.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e100.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e100.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eANOVA summary table for the analysis of habitat type differences between the up-estuary area between Fox Point a portion of Little Bay and down-estuary from Fox Point to the area around Goat Island\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eSource of variation\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003edf\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003eMS\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eF\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003e1-β\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003elocation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.570\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e3.83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.051\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.50\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ehabitat type\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e7.311\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e49.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.00\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003elocation*habitat type\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.704\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e4.72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.98\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ewithin Groups (Error)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e304\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.149\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTotal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e315\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e8.734\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eOverall, Shannon-Weiner indices (\u003cem\u003eH\u003c/em\u003e) were higher and significantly different at GI (\u003cem\u003eH\u003c/em\u003e\u003csub\u003eAVG\u003c/sub\u003e = 0.75 \u0026plusmn; 0.041, \u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;55) compared with LB (\u003cem\u003eH\u003c/em\u003e\u003csub\u003eAVG\u003c/sub\u003e = 0.56 \u0026plusmn; 0.49, \u003cem\u003en\u003c/em\u003e\u0026thinsp;=\u0026thinsp;51) (1-way ANOVA; \u003cem\u003eF\u003c/em\u003e\u0026thinsp;=\u0026thinsp;8.312; \u003cem\u003edf\u003c/em\u003e\u0026thinsp;=\u0026thinsp;1, 102; \u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.005), indicating a more diverse and even habitat composition around GI than in LB.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eDiver surveys\u003c/h2\u003e \u003cp\u003eSCUBA surveys at both study areas verified that the habitat videos captured during the underwater video surveys were representative of the six habitat types that could be quantified by divers (one-way ANOVAs, \u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05; Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). A total of 22 lobsters were counted at LB dive sites compared with 53 lobsters at GI.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eElements of habitat quality and associated spatial patterns in an area can appreciably shape the distribution, movements, and population structure of local marine species, including large mobile decapod crustaceans (Pitman and McAlpine 2003; Nathan \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Chang et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Florko et al. \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). The impetus for this study was to determine if differences in habitat composition were related to where lobsters are known to reside in GBE as well as those areas where lobsters are in comparably lower numbers, and we used habitat as a proxy for examining this hypothesis. Although larger scale bathymetry and general habitat features of the GBE have been mapped (NOAA-NCEI 2018; CCOM-JHC 2022), this study was aimed at quantifying and describing habitat features that were associated with known areas of lobster residency at a more detailed biological resolution (i.e., microhabitat) through a combination of video and dive surveys. Overall, our findings suggest that habitat composition was markedly different between areas on the up-estuary, south side of Fox Point, in LB, and the region slightly down-estuary, northeast of Fox Point, near GI, where lobsters are known to reside and often overwinter (Langley \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2017\u003c/span\u003e; Moore et al. \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Habitats in the vicinity of GI were more complex than in LB, and best described as \u0026lsquo;ocean-like\u0026rsquo;; with patches of kelp interspersed with cobble and boulder fields (Becker \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e1994\u003c/span\u003e; Grizzle \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e2005\u003c/span\u003e). Mathieson et al. (\u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e1981\u003c/span\u003e; \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e1983\u003c/span\u003e) described a variety of flora associated with these habitats including subtidal kelp (\u003cem\u003eLaminaria digitata\u003c/em\u003e) beds (i.e., estuarine tidal rapids) that are more typical of coastal nearshore areas than estuaries. Although the areas in LB south of FP contained some patches of cobble, especially closer to FP, most of the region that was surveyed was made up-estuary of extensive sand and mud flats.\u003c/p\u003e \u003cp\u003eBecker (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e1994\u003c/span\u003e) conducted a more extensive SCUBA survey of habitat composition in LB and an adjacent cove just downstream of our GI survey site and she found a measurable difference in bottom cover between the two sites. Becker (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e1994\u003c/span\u003e) also quantified over 15 types of bottom cover, including six types of cobble and boulder size compositions, and reported that \u0026gt;\u0026thinsp;80% of the coverage in the lower reaches of GBE were composed of cobble-boulder complexes, compared with 80% soft-sediment coverage upstream of FP. It was somewhat surprising that cobble habitat was not statistically different between the two sites examined in the current study, but this may be due to the size of the areas examined, which were much smaller in our study than those surveyed by Becker, and the criteria used to identify cobble features. What is generally termed \u0026lsquo;rocky habitat\u0026rsquo; (i.e., boulder and cobble) was analyzed as separate categories for our study (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), but sometimes they are combined. For example, Selgrath et al. (\u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e2007\u003c/span\u003e) defines cobble as \u0026ldquo;a mixture of unconsolidated pebbles, cobbles, and boulders, 1-400 cm\u0026rdquo;. When we carried out an additional ANOVA analysis between our two study sites, in which we combined cobble and boulder into one type of cover, we found a significant difference (one-way ANOVA, p\u0026thinsp;=\u0026thinsp;0.018); with a total coverage of 66% and 48% for GI and FP, respectively.\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eUse of complex habitats by lobsters\u003c/h2\u003e \u003cp\u003eIt was not surprising that we found an order of magnitude more lobsters in the complex habitats around GI, than up-estuary in LB. The affinity of lobsters for complex habitats has been documented in many other cases (e.g., Karnofsky 1989; Chang et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2010\u003c/span\u003e) and Becker (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e1994\u003c/span\u003e) in our study area. Becker also reported that \u0026gt;\u0026thinsp;50% of all lobsters found in dive surveys downstream of FP were between 40\u0026ndash;60 mm carapace length (CL), including a number of very small, newly recruited, lobsters (10\u0026ndash;30 mm CL). Complex habitats such as cobble, boulder, and algal beds provide shelter and foraging for juvenile lobsters (Wahle and Steneck \u003cspan citationid=\"CR73\" class=\"CitationRef\"\u003e1991\u003c/span\u003e; see Lawton and Lavalli \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e1995\u003c/span\u003e, for review) and some studies suggest a positive correlation between complex habitats and the presence of a variety of sizes of lobsters (Acosta \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e1999\u003c/span\u003e; Selgrath et al. \u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e2007\u003c/span\u003e; Young et al. \u003cspan citationid=\"CR76\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). Often referred to as microhabitat features, such areas can support a variety of flora and fauna, which influence the distribution of organisms in particular areas (Saunders et al. \u003cspan citationid=\"CR60\" class=\"CitationRef\"\u003e1991\u003c/span\u003e). The higher diversity index (\u003cem\u003eH)\u003c/em\u003e in habitat coverage at GI compared with LB is consistent with diver observations and video images of the complex habitats in the area around GI.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eLobster movements and their distribution in Little Bay\u003c/h2\u003e \u003cp\u003eWhile it has been well documented that some lobsters from the coast and the connecting Piscataqua River transit up into the GBE during the summer months, and some lobsters do the reverse in the fall (Watson et al. \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e1999\u003c/span\u003e), it remains unclear how many lobsters reside year around in the GBE. In 2007, over 30 lobsters (70\u0026ndash;90 mm CL) were tagged at GI and, although some moved a short distance (~\u0026thinsp;0.5 km) toward the coast, most remained near their original tagging location for a full season (Langley \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). By comparison, lobsters tagged and released in 2008 in LB showed a net movement toward GI, suggesting the habitat near GI is more favorable than in LB. Subsequently, Moore et al. (\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) used acoustic telemetry to track a total of nine ovigerous females captured near GI in October and they all remained in that area throughout the winter and into the spring, when their eggs likely hatched. While there are few, if any, reports of year-round resident adult lobster populations in estuarine systems (e.g., Wahle \u003cspan citationid=\"CR71\" class=\"CitationRef\"\u003e1993\u003c/span\u003e), our results appear to suggest that some proportion of lobsters in the GBE reside there year-round and contribute new recruits as well, helping to further the connectivity and ecological importance of estuarine coastal habitats for some lobster populations. Furthermore, our data reinforce the possibility that a proportion of adult lobsters in GBE prefer complex habitats surrounding GI, especially while they overwinter.\u003c/p\u003e \u003cp\u003eAlthough environmental cues and conditions (e.g., temperature, salinity) are likely to affect lobster movements and the habitat suitability of certain regions of the GBE (Watson et al. \u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e1999\u003c/span\u003e; Goldstein and Watson \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Jury et al. \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Moore et al. \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2020\u003c/span\u003e), appropriate bottom features (e.g., hardbottom, kelp beds, cobble) may also influence lobster residency. For example, Geraldi et al. (\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2009\u003c/span\u003e) found that lobsters caught in rocky, complex substrates moved far less than those captured and released in soft sediment habitats. Specifically, 82% of lobsters caught on rocky substrate were again caught in the same habitat. Furthermore, this study suggested that some areas of sediment between bedrock outcroppings or deep channels may serve as habitat corridors for short- or long-term movements of lobsters seeking sheltering habitats (Geraldi et al. \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2009\u003c/span\u003e). Additionally, both Estrella and Morrissey (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e1997\u003c/span\u003e) and Watson et al. (\u003cspan citationid=\"CR74\" class=\"CitationRef\"\u003e1999\u003c/span\u003e) found that lobsters were more likely to move (and did so rapidly) when presented with suboptimal habitats on outer Cape Cod and in Great Bay Estuary, respectively. Clearly, more work is needed to better determine the relationship between habitat bottom type, marine landscape, and movements of lobsters (both transient and resident) as a key consideration for continued and improved lobster management.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eImpact of habitat on lobster movements\u003c/h2\u003e \u003cp\u003eThe present study expands upon previous studies of lobster movements and reproduction in the GBE (references herein) and demonstrates that lobsters in the GBE tend to concentrate and reside in regions of preferred habitat, such as in the vicinity of GI, where the benthic conditions resemble those along the NH (southern Gulf of Maine) coastline. Thus, locations such as these provide direct benefits to local lobster populations and the fishery. For example, Rowe (\u003cspan citationid=\"CR59\" class=\"CitationRef\"\u003e2002\u003c/span\u003e) found that no-take reserves in Bonavista Bay, Newfoundland in suitable lobster habitat increased lobster density, most likely by offering a high density of shelters for egg-producing females. Similarly, Selgrath et al. (\u003cspan citationid=\"CR61\" class=\"CitationRef\"\u003e2007\u003c/span\u003e) reported that patchy environments (particularly edges), that included cobble and seagrass, were integral to the survival and distribution of lobsters over a range of sizes. Similar fragmented and insular habitats (such as estuaries) are also known to hold significant refuge value, serve as movement conduits, and influence predator-prey dynamics for a variety of crustaceans including lobsters (Acosta \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e1999\u003c/span\u003e; Micheli and Peterson \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e1999\u003c/span\u003e; Hovel and Lipcius \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e2001\u003c/span\u003e; Grabowski et al. \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Hovel and Wahle \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2010\u003c/span\u003e; Yeager and Hovel \u003cspan citationid=\"CR75\" class=\"CitationRef\"\u003e2017\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThere are several reasons why complex estuarine habitats, such as those around GI likely benefit lobsters in the GBE. First, they provide safe habitats for ovigerous females because of the abundance of suitable shelters. Second, conditions during the winter tend to be relatively calmer (i.e., less impact from storms), compared with most areas along the coast. Goldstein and Watson (\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2015\u003c/span\u003e) found that lobsters along the New Hampshire coast (mouth of the Piscataqua River) tended to move offshore in the fall, as storms became severe enough to cause considerable turbulence. Third, in the spring, the GBE exhibits a much faster rate of temperature increase in the spring compared with coastal waters, so, as documented by Moore et al. (\u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2020\u003c/span\u003e) larvae hatch sooner and gain an accelerated start on their planktonic development phase. And finally, the larvae that hatch here might also be retained and settle in a more suitable habitat for their development. Previous research has shown that ocean surface drifters released around FP and GI tended to be retained locally over a period of 2\u0026ndash;3 weeks (Goldstein \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2012\u003c/span\u003e; Moore et al. \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e2020\u003c/span\u003e), so at least a share of larvae released in this area might settle in the cobble fields and macroalgal beds that are preferred by early benthic phase lobsters (Wahle and Steneck \u003cspan citationid=\"CR73\" class=\"CitationRef\"\u003e1991\u003c/span\u003e; \u003cspan citationid=\"CR72\" class=\"CitationRef\"\u003e1992\u003c/span\u003e). As such, the present study strongly suggests that these areas could be considered essential lobster nursery habitat (Dahlgren et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2006\u003c/span\u003e), at least for estuarine lobsters.\u003c/p\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003e Support for this project was provided by the UNH Graduate School Summer Fellowship Program, the Great Bay Steward\u0026rsquo;s Foundation, as well as a NOAA-NERR Graduate Research Fellowship to JSG.\u003c/p\u003e\u003ch2\u003eAcknowledgements\u003c/h2\u003e \u003cp\u003eWe are grateful to Dave Shay, Krystin Ward, and Kate Masury for their help and support in the field. We thank Jacob Aman at Wells NERR for his GIS expertise with Fig.\u0026nbsp;1.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e \u003cp\u003eData sets generated and used in this study may be available from the corresponding author upon reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAtlantic Coastal Cooperative Statistics Program (ACCSP). 2023. Data Warehouse online application, Arlington, VA. Available at \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.accsp.org\u003c/span\u003e\u003cspan address=\"https://www.accsp.org\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Accessed 01 December 2023.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAcosta, C. A. 1999. 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Accounting for habitat and seafloor structure characteristics on southern rock lobster (\u003cem\u003eJasus edwardsii\u003c/em\u003e) assessment in a small marine reserve. \u003cem\u003eMarine Biology\u003c/em\u003e. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00227-016-2914-y\u003c/span\u003e\u003cspan address=\"10.1007/s00227-016-2914-y\" 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":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"estuaries-and-coasts","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"esco","sideBox":"Learn more about [Estuaries and Coasts](https://www.springer.com/journal/12237)","snPcode":"12237","submissionUrl":"https://www.editorialmanager.com/esco/","title":"Estuaries and Coasts","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Estuaries, Homarus americanus, lobster movements, video analyses, complex estuarine habitats","lastPublishedDoi":"10.21203/rs.3.rs-3844217/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-3844217/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eAlthough estuaries create many physiological challenges for lobsters (\u003cem\u003eHomarus americanus\u003c/em\u003e), there may also be some advantages for lobsters residing in these unique systems. While some lobsters in the Great Bay Estuary (GBE) make seasonal migrations into and out of the GBE, many remain year-round, including ovigerous (egg-bearing) females. Furthermore, lobsters that are resident in the GBE tend to aggregate in specific areas. The overall goal of this study was to determine why lobsters (both ovigerous and non-ovigerous) tend to spend more time in certain areas of the GBE. Specifically, we set out to test the hypothesis for two disparate areas of GBE that have features potentially making them conducive habitats for long-term lobster residency. We used a combination of habitat mapping using underwater videography and diver surveys to compare areas where lobsters aggregated compared with those areas where lobster density was known to be low. Areas where lobsters spent the most time in GBE were similar to coastal marine habitats, comprised mostly of rocky (hardbottom) complexes interspersed with macroalgae. In contrast, areas with the fewest lobsters were primarily comprised of sandy, soft sediment. The strong relationship between complex, rocky habitats and lobster residency in GBE suggest that habitat quality in other estuaries might have a strong impact on the distribution, abundance, and residency of lobsters and increases the likelihood that some estuaries may support year-round resident lobster populations.\u003c/p\u003e","manuscriptTitle":"The potential influence of habitat composition on seasonal lobster movements and their distribution in the Great Bay Estuary, New Hampshire","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-02-01 19:14:25","doi":"10.21203/rs.3.rs-3844217/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2024-02-13T15:06:10+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-01-30T03:52:53+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"Estuaries and Coasts","date":"2024-01-09T18:10:46+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-01-07T16:21:37+00:00","index":"","fulltext":""},{"type":"submitted","content":"Estuaries and Coasts","date":"2024-01-07T11:04:37+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"estuaries-and-coasts","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"esco","sideBox":"Learn more about [Estuaries and Coasts](https://www.springer.com/journal/12237)","snPcode":"12237","submissionUrl":"https://www.editorialmanager.com/esco/","title":"Estuaries and Coasts","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"7818d366-4425-4217-a900-92582873177a","owner":[],"postedDate":"February 1st, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-10-28T16:09:02+00:00","versionOfRecord":{"articleIdentity":"rs-3844217","link":"https://doi.org/10.1007/s12237-024-01445-5","journal":{"identity":"estuaries-and-coasts","isVorOnly":false,"title":"Estuaries and Coasts"},"publishedOn":"2024-10-24 15:57:03","publishedOnDateReadable":"October 24th, 2024"},"versionCreatedAt":"2024-02-01 19:14:25","video":"","vorDoi":"10.1007/s12237-024-01445-5","vorDoiUrl":"https://doi.org/10.1007/s12237-024-01445-5","workflowStages":[]},"version":"v1","identity":"rs-3844217","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3844217","identity":"rs-3844217","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}