Objective Atlantic Striped Bass Morone saxatilis are one of the most economically important fish species on the U.S. East Coast; however, trends in growth have not been recently evaluated despite concerns about the health and status of the stock. Our objective was to use otolith-aged fish from a combination of fishery-independent and fishery-dependent sources to evaluate growth of Striped Bass from 1998 to 2019 in the mid-Atlantic region of the U.S. East Coast.Methods We used general linear models to describe temporal changes in weight at age and length at age for Striped Bass by sex and a linear mixed effects model to characterize temporal changes in Striped Bass weight at length.Results Striped Bass length and weight at age increased primarily for ages 10-14 between 1998 and 2019 for both sexes. Increases in length at age during 1998-2019 for male Striped Bass ages 10-14 averaged 8.9 cm (+/- 5 cm; range 0.9-14.9 cm), and female Striped Bass ages 10-15 averaged 7.8 cm (+/- 0.5 cm; range 7.0-8.4 cm). For male and female Striped Bass ages 10-14, there was an almost 3 kg (+/- 0.94 kg) increase in mean weight across the time series, and the percentage of change in the mean weight of males was nearly two times as great for females. Additionally, we found that female Striped Bass continued to increase in both length and weight up to ages 22 or older. The relationship between length and weight changed during 1998-2019 such that Striped Bass of a given length weighed more later in the time series. Density-dependent effects on length and weight at age were identified.Conclusions Striped Bass of intermediate ages increased in size at age from 1998 to 2019, and female Striped Bass weight continued to accumulate through approximately age 22. The method used to age Striped Bass influenced the characterization of growth such that otolith-based weight at age is generally lower than scale-based or a mixture of scale- and otolith-based weight at age. Striped Bass size at age for intermediate ages and both sexes increased during 1998-2019. Otolith-based size at age was generally lower than scale-based. Given bias and imprecision of scale ages, we recommend that Striped Bass age determination transition from scales to otoliths coastwide.

Multispecies models have existed in a fisheries context since at least the 1970s, but despite much exploration, advancement, and consideration of multispecies models, there remain limited examples of their operational use in fishery management. Given that species and fleet interactions are inherently multispecies problems and the push towards ecosystem-based fisheries management, the lack of more regular operational use is both surprising and compelling. We identify impediments hampering the regular operational use of multispecies models and provide recommendations to address those impediments. These recommendations are: (1) engage stakeholders and managers early and often; (2) improve messaging and communication about the various uses of multispecies models; (3) move forward with multispecies management under current authorities while exploring more inclusive governance structures and flexible decision-making frameworks for handling tradeoffs; (4) evaluate when a multispecies modelling approach may be more appropriate; (5) tailor the multispecies model to a clearly defined purpose; (6) develop interdisciplinary solutions to promoting multispecies model applications; (7) make guidelines available for multispecies model review and application; and (8) ensure code and models are well documented and reproducible. These recommendations draw from a global assemblage of subject matter experts who participated in a workshop entitled "Multispecies Modeling Applications in Fisheries Management".

Globally, climate change is inducing range shifts and expansions for numerous species. For commercially exploited species, such as those in directed fisheries, this can cause numerous issues with management and jurisdictions as the species shift and expand into areas at levels previously unseen. The black sea bass ( Centropristis striata) fishery has rapidly expanded in the northern Atlantic. Over the past decade commercial landings have more than doubled in the New England and Mid-Atlantic regions. This increase is related to a northward shift in the species’ center of biomass and range expansion. There is a crucial need for increased data in this species’ northern range. Oftentimes, large-scale fisheries data collection is limited by available resources and the difficulty of collecting data at-sea. Citizen science, such as fishing industry-based Research Fleets, represent a cost-effective option to help overcome these limitations and allow for the rapid collection of large amounts of data. The Commercial Fisheries Research Foundation and Rhode Island Department of Environmental Management established the Black Sea Bass Research Fleet in 2016. The Research Fleet is composed of fishers representing a variety of gear types who collect fishery-dependent data on black sea bass at-sea on a custom tablet application. In five years, 20 captains participated in the Research Fleet and collected length, visually-identified sex, and disposition data on 40,939 individual black sea bass throughout southern New England and into the Mid-Atlantic Bight. Catch, effort, and basic environmental data from 2,288 sampling sessions have been collected alongside this biological data. We apply the collaborative Research Fleet approach to a finfish for the first time and evaluate its performance over the first five years of sampling through participant engagement, magnitude of data collection, and interest in collected data. Further, we introduce the next steps being undertaken to incorporate the collected data into the management framework. This project illustrates that a science-industry research collaboration such as the Black Sea Bass Research Fleet can consistently collect large amounts of fishery-dependent data on black sea bass, and highlights a mutual interest among fishers, scientists, and managers to expand the collection of reliable data on this important species.

Ecosystem models have emerged as vital tools for evaluating management strategies and are increasingly used by policymakers. We reviewed the history of modeling and identified research gaps based on policy needs for ecosystem-based management of Narragansett Bay (RI, USA)—a highly-impacted system with a history of research and monitoring dating back to the 1950s. There is a need to disentangle the impacts of nutrient reductions versus climate change on species interactions as well as understand the ecological and socio-economic tradeoffs of management actions. Within this context, we consider the following to be important for future research and creation of ecosystem models for Narragansett Bay: (i) account for multi-scale processes and patterns through two-way model coupling; (ii) incorporate human behavior as part of model predictions; and (iii) lessen the impact of model uncertainty by identifying robust management strategies that will sustain resources under a range of potential future scenarios. Ecosystem modeling that builds on prior models and is informed by knowledge gaps will be a powerful tool to operationalize ecosystem-based management in Narragansett Bay and globally, providing sustainable pathways for nature and people.

Within fisheries, stakeholders often have varying viewpoints regarding natural marine resources, and use different sets information to evaluate their condition. Evaluating a resource with different sets of information can lead to different conclusions. Windowpane flounder (Scophthalmus aquosus) are a managed finfish species in the northwest Atlantic whose regulations have the potential to limit harvest opportunities for target species. We analyzed commercial trip and catch information from video data to understand local densities of windowpane flounder in conjunction with fisheries independent surveys. Video monitoring data from three Rhode Island commercial fisher's vessels and fisheries independent trawl survey data were analyzed to understand the geographic distribution of the stock as well as overlap with temporary closed areas. Biomass data from the fisheries-dependent and fisheries-independent surveys were combined with a spatial-temporal model that accounted for differences in catchability among vessels and spatial autocorrelation. A separate analysis of estimated discard rates with observer data was also conducted to determine how the distribution of windowpane discards in Southern New England compared to the distribution of model predicted windowpane abundance. In agreement with the fishermen's observations, the temporary closed areas were not located where the highest densities of windowpane flounder occurred. The temporary closed areas, however, were located where the highest rates of discards occurred and thus where fishing had the greatest impact on the stock. The integration of verified fishery-dependent data with the scientific surveys has the potential to create a single set of information that is trusted by all user groups.

Atlantic menhaden ( Brevoortia tyrannus ) support the largest fishery by volume on the United States East Coast, while also playing an important role as a forage species. Managers’ and stakeholders’ increasing concerns about the impact of Atlantic menhaden harvest on ecosystem processes led to an evolution in the assessment and management of this species from a purely single-species approach to an ecosystem approach. The first coastwide stock assessment of Atlantic menhaden for management used a single-species virtual population analysis (VPA). Subsequent assessments used a forward projecting statistical catch-at-age framework that incorporated estimates of predation mortality from a multispecies VPA while analytical efforts continued toward the development of ecosystem models and explicit ecological reference points (ERPs) for Atlantic menhaden. As an interim step while ecosystem models were being developed, a series of ad hoc measures to preserve Atlantic menhaden biomass for predators were used by managers. In August 2020, the Atlantic States Marine Fisheries Commission formally adopted an ecological modeling framework as a tool to set reference points and harvest limits for the Atlantic menhaden that considers their role as a forage fish. This is the first example of a quantitative ecosystem approach to setting reference points on the United States Atlantic Coast and it represents a significant advance for forage fish management. This case study reviews the history of Atlantic menhaden stock assessments and management, outlines the progress on the current implementation of ERPs for this species, and highlights future research and management needs to improve and expand ecosystem-based fisheries management.

Marine fisheries represent a social-ecological system driven by both complex ecological processes and human interactions. Ecosystem-based fisheries management requires an understanding of both the biological and social components, and management failure can occur when either are excluded. Despite the significance of both, most research has focused on characterizing biological uncertainty rather than on better understanding the impacts of human behavior because of the difficulty of incorporating human behavior into simulation models. In this study, we use the fisheries in Narragansett Bay (Rhode Island, USA) as a case study to demonstrate how coupled modeling can be used to represent interactions between the food web and fishers in a social-ecological system. Narragansett Bay holds both a commercial fishery for forage fish, i.e., Atlantic menhaden (Brevoortia tyrannus) and a recreational fishery for their predators, i.e. striped bass (Morone saxatilis) and bluefish (Pomatomus saltatrix). To explore trade-offs between these two fisheries, we created a food web model and then coupled it to a recreational fishers' behavior model, creating a dynamic social-ecological representation of the ecosystem. Fish biomass was projected until 2030 in both the stand-alone food web model and the coupled social-ecological model, with results highlighting how the incorporation of fisher behavior in modeling can lead to changes in the ecosystem. We examined how model outputs varied in response to three attributes: (1) the forage fish commercial harvest scenario, (2) the predatory (piscivorous) fish abundance-catch relationship in the recreational fishery, and (3) the rate at which recreational fishers become discouraged (termed "satisfaction loss"). Higher commercial harvest of forage fish led to lower piscivorous fish biomass but had minimal effects on the number of piscivorous fish caught recreationally or recreational fisher satisfaction. Both the abundancecatch relationship and satisfaction loss rate had notable effects on the fish biomass, the number of fish caught recreationally, and recreational fisher satisfaction. Currently, the lack of spatial and location-specific fisher behavior data limits the predictive use of our model. However, our modeling framework shows that fisher behavior can be successfully incorporated into a coupled social-ecological model through the use of agent-based modeling, and our results highlight that its inclusion can influence ecosystem dynamics. Because fisher decision making and the ecosystem can influence one another, social responses to changing ecosystems should be explicitly integrated into ecosystem modeling to improve ecosystem-based fisheries management efforts.

Managers, stakeholders, and scientists recognize the need for collaborative, transparent, integrated approaches to complex resource management issues, and frameworks to address these complex issues are developing. Through the course of 2019, the Mid-Atlantic Fishery Management Council developed a conceptual model of ecosystem linkages and risks for summer flounder, a species of recreational and commercial fisheries importance. The proximal aim of the model was to develop a list of integrated management questions that could be refined and addressed through a future quantitative management strategy evaluation. As such, this conceptual model served as a scoping tool. However, the true value of the conceptual model lays elsewhere: familiarizing resource managers historically focused on single-species management with the potential utility of an ecosystem approach to management. This paper details the goals and development of the conceptual model and situates this process in the broader context of best practices for collaborative open science and scientific reproducibility. Further, it highlights a successful path by which the shift towards ecosystem-based management can be actuated.

Atlantic menhaden is an important forage fish and the target of the largest fishery along the US East Coast by volume. Since 1999, managers at the Atlantic States Marine Fisheries Commission, stakeholders, and scientists have been interested in developing ecological reference points (ERPs) that account for menhaden’s role as a forage species. To accomplish this, we developed a suite of modeling approaches that incorporated predation on menhaden and changes in productivity over time and allowed for evaluation of trade-offs between menhaden harvest and ecosystem management objectives. These approaches ranged in complexity, from models with minimal data requirements and few assumptions to approaches with extensive data needs and detailed assumptions. This included a surplus production model with a time-varying intrinsic growth rate, a Steele-Henderson surplus production model, a multispecies statistical catch-at-age model, an Ecopath with Ecosim (EwE) model with a limited predator and prey field, and a full EwE model. We evaluated how each model could address managers’ objectives and compared outputs across the approaches, highlighting their strengths, weaknesses, and management utility. All models produced estimates of age-1 + biomass and exploitation rate that were similar in trend and magnitude to the single-species statistical catch-at-age model, especially in recent years. While the less complex models were relativity easy to implement and update, they lacked key elements needed to manage multiple species simultaneously. More complex models required a wider array of data and were more difficult to update within the current management time-frames, but produced a more useful framework for managers. Ultimately, an EwE model of intermediate complexity coupled with the existing single-species assessment model was recommended for use in management.

Fish populations with broad age distributions are expected to have higher reproductive capacity than age-truncated populations because of the disproportionate contributions of older fish. Harvest slot limits, an expected means of ameliorating age truncation, are modeled for Tautog Tautoga onitis in an overfished population subunit that is experiencing overfishing. Tautog, currently managed with a 40-cm minimum size limit (MSL), is a candidate species for slots because it is relatively long-lived and slow-growing, with low discard mortality. We evaluated changes in biomass and abundance at age relative to management with the current MSL regulations using a forward population simulation model for four slots: 35-45 cm (small-wide), 38-42 cm (small-narrow), 40-50 cm (large-wide), and 43-47 cm (large-narrow), inclusive of lower and upper length limits. Angler behavioral responses were evaluated at 0, 10, and 20% noncompliance with the upper slot limit. The biomass and number of fish removed were reduced with harvest slot limit management relative to the MSL, but because the harvest was redirected to smaller fish the reduction in numbers removed was not as large as the reduction in biomass removed. Slot limits broadened the age structure within 10 years by reducing fishing mortality on extant fish. Median spawning stock biomass (SSB) recovered more quickly in three of the slots than with MSL regulation (3-6 years to reach SSB associated with a fishing mortality that yields 30% spawners per recruit as compared to 9 years with MSL management). We concluded that harvest slot limits can broaden age structure and restore biomass in overfished fisheries, but they should be evaluated when managing coastal fisheries as a reduction in biomass removed is required.

Southern New England salt marsh vegetation and habitats are changing rapidly in response to sea-level rise. At the same time, fiddler crab ( Uca spp.) distributions have expanded and purple marsh crab ( Sesarma reticulatum ) grazing on creekbank vegetation has increased. Sea-level rise and reduced predation pressure drive these changing crab populations but most studies focus on one species; there is a need for community-level assessments of impacts from multiple crab species. There is also a need to identify additional factors that can affect crab populations. We sampled crabs and environmental parameters in four Rhode Island salt marshes in 2014 and compiled existing data to quantify trends in crab abundance and multiple factors that potentially affect crabs. Crab communities were dominated by fiddler and green crabs ( Carcinus maenas ); S. reticulatum was much less abundant. Burrow sizes suggest that Uca is responsible for most burrows. On the marsh platform, burrows and Carcinus abundance were negatively correlated with elevation, soil moisture, and soil percent organic matter and positively correlated with soil bulk density. Uca abundance was negatively correlated with Spartina patens cover and height and positively correlated with Spartina alterniflora cover and soil shear strength. Creekbank burrow density increased dramatically between 1998 and 2016. During the same time, fishing effort and the abundance of birds that prey on crabs decreased, and water levels increased. Unlike in other southern New England marshes where recreational overfishing is hypothesized to drive increasing marsh crab abundance, we propose that changes in crab abundance were likely unrelated to recreational finfish over-harvest; instead, they better track sea-level rise and changing abundances of alternate predators, such as birds. We predict that marsh crab abundance will continue to expand with ongoing sea-level rise, at least until inundation thresholds for crab survival are exceeded.

This study evaluated the relative importance of the Narragansett Bay estuary (RI and MA, USA), and associated tidal rivers and coastal lagoons, as nurseries for juvenile winter flounder, Pseudopleuronectes americanus , and summer flounder, Paralichthys dentatus . Winter flounder (WF) and summer flounder (SF) abundance and growth were measured from May to October (2009–2013) and served as indicators for the use and quality of shallow-water habitats (water depth <1.5–3.0 m). These bioindicators were then analyzed with respect to physiochemical conditions to determine the mechanisms underlying intraspecific habitat selection. WF and SF abundances were greatest in late May and June (maximum monthly mean = 4.9 and 0.55 flounder/m 2 for WF and SF, respectively) and were significantly higher in the tidal rivers relative to the bay and lagoons. Habitat-related patterns in WF and SF abundance were primarily governed by their preferences for oligohaline (0.1–5 ppt) and mesohaline (6–18 ppt) waters, but also their respective avoidance of hypoxic conditions (<4 mg DO/L) and warm water temperatures (>25 °C). Flounder habitat usage was also positively related to sediment organic content, which may be due to these substrates having sufficiently high prey densities. WF growth rates (mean = 0.25 ± 0.14 mm/day) were negatively correlated with the abundance of conspecifics, whereas SF growth (mean = 1.39 ± 0.46 mm/day) was positively related to temperature and salinity. Also, contrary to expectations, flounder occupied habitats that offered no ostensible advantage in intraspecific growth rates. WF and SF exposed to low salinities in certain rivers likely experienced increased osmoregulatory costs, thereby reducing energy for somatic growth. Low-salinity habitats, however, may benefit flounder by providing refugia from predation or reduced competition with other estuarine fishes and macroinvertebrates. Examining WF and SF abundance and growth across each species’ broader geographic distribution revealed that southern New England habitats may constitute functionally significant nurseries. These results also indicated that juvenile SF have a geographic range extending further north than previously recognized.

Two of the most ecologically and economically important species in the Mid- Atlantic Bight are Atlantic menhaden and the Atlantic striped bass. These species are important for human prosecuted fisheries, but these two species are also closely linked through ecosystem dynamics that are influenced by interactions between these species such as through predation. Beyond striped bass and menhaden, there are also other important species that are linked in this ecosystem. The focus of this dissertation is to estimate the trophic interactions among several important fish species in the Mid- Atlantic Bight, with an emphasis on the interactions between menhaden and striped bass. These species interactions are estimated by developing a multispecies, statistical catch-at-age model of a community of Mid-Atlantic species that explicitly quantifies the mortality due to predation.