Aquaculture and Fisheries Commons^™

Saved By The Shell: Oyster Reefs Can Shield Juvenile Blue Crabs Callinectes Sapidus, Katherine S. Longmire, Rochelle D. Seitz, Alison Smith, Romuald N. Lipcius

VIMS Articles

Juvenile blue crabs Callinectes sapidus use seagrass and other structured habitats as refuges from predation. Oyster reef habitats provide structural complexity that may offer refuge, but the value of these habitats for juvenile blue crabs has not been examined. We quantified survival of juvenile C. sapidus in structured oyster reef habitat versus unstructured soft-bottom habitat. In a field tethering experiment in the York River, lower Chesapeake Bay (USA), juvenile C.sapidus (10−50 mm carapace width [CW]) were tethered in sand (n = 40) or oyster reef (n = 39)habitats at subtidal sites 1−2 m deep. An underwater camera system was used …

Methods For Identifying Species Complexes Using A Novel Suite Of Multivariate Approaches And Multiple Data Sources: A Case Study With Gulf Of Alaska Rockfish, Kristen L. Omori, Cindy A. Tribuzo, Elizabeth A. Babcock, John M. Hoenig

VIMS Articles

International and national laws governing the management of living marine resources generally require specification of harvest limits. To assist with the management of data-limited species, stocks are often grouped into complexes and assessed and managed as a single unit. The species that comprise a complex should have similar life history, susceptibility to the fishing gear, and spatial distribution, such that common management measures will likely lead to sustainable harvest of all species in the complex. However, forming complexes to meet these standards is difficult due to the lack of basic biological or fisheries data to inform estimates of biological vulnerability …

Attainability Of Accurate Age Frequencies For Ocean Quahogs (Arctica Islandica) Using Large Datasets: Protocol, Reader Precision, And Error Assessment, Kathleen M. Hemeon, Eric N. Powell, Eric Robillard, Sara M. Pace, Theresa E. Redmond, Roger Mann

VIMS Articles

Ocean quahogs (Arctica islandica) are the longest lived bivalve on Earth. Individuals on the deep continental shelf off Georges Bank can survive for centuries, and in the colder, boreal waters of Iceland, ages over 500 y can be reached. Ocean quahog landings in the United States represent a $24 million industry, yet assessment models operate with no age data because of the substantial sample size required to develop adequate population age distributions for such a long-lived species, the unknown error associated with age estimates, and the extensive time and financial investment required to create production-scale age datasets. Inclusion …

Modeling Oyster Reef Restoration: Larval Supply And Reef Geometry Jointly Determine Population Resilience And Performance, Romuald N. Lipcius, Yi Zhang, Jingyi Zhou, Leah B. Shaw, Junping Shi

VIMS Articles

Restoration of native oyster (Crassostrea virginica) populations in Chesapeake Bay shows great promise after three decades of failed attempts. Population models used to inform oyster restoration had integrated reef habitat quality, demonstrating that reef height determines oyster population persistence and resilience. Larval recruitment drives population dynamics of marine species, yet its impact with reef height and sediment deposition upon reef restoration is unknown. To assess the influence of reef height, sediment deposition and larval supply, we adapted a single-stage population model to incorporate stage structure using a system of four differential equations modeling change in juvenile density (J), …

Reproductive Characteristics Differ In Two Invasive Populations Of Blue Catfish, Vaskar Nepal, Mary C. Fabrizio

VIMS Articles

The management of invasive Blue CatfishIctalurus furcatusin Chesapeake Bay tributaries is hindered by the lackof information on its reproductive biology, which is a key component of population models used to forecast abun-dance. We quantified and compared the reproductive traits of female Blue Catfish from two populations from the tidalreaches of the James and York River subestuaries during 2015–2017. In these systems, Blue Catfish matured betweenthe ages of 6 and 10 years and spawned between May and July, with largerfish spawning earlier in the season. Dur-ing spawning events, Blue Catfish produced 2,613–68,356 eggs, with larger and olderfish producing more eggs. Fishin …

Effects Of Food Limitation On Growth, Body Condition And Metabolic Rates Of Non-Native Blue Catfish, Vaskar Nepal, Mary C. Fabrizio, Richard Brill

VIMS Articles

Establishment and range expansion of non-native species in novel habitats depend on their energetic requirements and food availability. Knowledge of growth and metabolic rates of non-native fishes at various food levels is particularly critical to inform models that assess their invasion potential. We compared growth rates, body condition and metabolic rates of juvenile blue catfish (Ictalurus furcatus), an invasive species in many lakes, coastal rivers and estuaries throughout the Eastern USA, at three ration levels: ad libitum (3.5% of fish body mass/d), two-third ad libitum and one-third ad libitum. All fish survived the entire duration of the experiment (4 months) …

The Extent Of Seasonally Suitable Habitats May Limit Forage Fish Production In A Temperate Estuary, Mary C. Fabrizio, Troy D. Tuckey, Aaron J. Bever, Michael L. Macwilliams

VIMS Articles

The sustained production of sufficient forage is critical to advancing ecosystem-based management, yet factors that affect local abundances and habitat conditions necessary to support aggregate forage production remain largely unexplored. We quantified suitable habitat in the Chesapeake Bay and its tidal tributaries for four key forage fishes: juvenile spotted hake Urophycis regia, juvenile spot Leiostomus xanthurus, juvenile weakfish Cynoscion regalis, and bay anchovy Anchoa mitchilli. We used information from monthly fisheries surveys from 2000 to 2016 coupled with hindcasts from a spatially interpolated model of dissolved oxygen and a 3-D hydrodynamic model of the Chesapeake Bay …

Environmentally-Determined Production Frontiers And Lease Utilization In Virginia's Eastern Oyster Aquaculture Industry, Jennifer Beckensteiner, Andrew M. Scheld, Pierre St-Laurent, Marjorie A.M. Friedrichs, David M. Kaplan

VIMS Articles

During the last decade, oyster aquaculture has rebounded in Virginia and has been associated with an increase in subaqueous leased area. Production levels remain historically low, however, and many leases are thought to be underutilized. This study uses a novel approach leveraging high-resolution environmental data to evaluate lease utilization and identify constraints on aquaculture development. Stochastic Frontier Analysis (SFA) and Data Envelopment Analysis (DEA) were used to define environmentally-determined production frontiers, i.e. production possibilities based on empirical observations of aquaculture production, available space, and environmental conditions. Both methods estimated Lease Capacity Utilization (LCU, from 0 to 1) for leases producing …

The Case Of The ‘Missing’ Arctic Bivalves And The Walrus: The Biggest [Overlooked] Clam Fishery On The Planet, Roger L. Mann, Eric N. Powell, Daphne M. Munroe

VIMS Articles

Bivalve molluscs represent a significant proportion of the diet of both Atlantic and Pacific walrus (Odobenus rosmarus rosmarus and Odobenus rosmarus divergens, respectively) and are pivotal to benthic–pelagic coupling and carbonate cycling in the Arctic oceans. The latter is of particular relevance in a period of seasonal ice retreat, freshwater release into associated surface waters, decreasing water pH, and possible undersaturation of Arctic waters with respect to aragonite. Using population estimates and predation rates for the walruses on bivalve molluscs, a conservative estimate of bivalve consumption in the regions of active walruses foraging is 2.0–3.0 3 106 tonnes y–1—a tonnage …

Estimating Shifts In Phenology And Habitat Use Of Cobia In Chesapeake Bay Under Climate Change, Daniel P. Crear, Brian E. Watkins, Marjorie A.M. Friedrichs, Pierre St-Laurent, Kevin C. Weng

VIMS Articles

Cobia (Rachycentron canadum) is a large coastal pelagic fish species that represents an important fishery in many coastal Atlantic states of the U.S. They are heavily fished in Virginia when they migrate into Chesapeake Bay during the summer to spawn and feed. These coastal habitats have been subjected to warming and increased hypoxia which in turn could impact the timing of migration and the habitat suitability of Chesapeake Bay. With conditions expected to worsen, we project current and future habitat suitability of Chesapeake Bay for cobia and predict changes in their arrival and departure times as conditions shift. To do …

The Power Struggle: Assessing Interacting Global Change Stressors Via Experimental Studies On Sharks, Ian A. Bouyoucos, Sue-Ann Watson, Serge Planes, Colin A. Simpfendorfer, Gail D. Schwieterman, Et Al

VIMS Articles

Ocean warming and acidification act concurrently on marine ectotherms with the potential for detrimental, synergistic effects; yet, effects of these stressors remain understudied in large predatory fishes, including sharks. We tested for behavioural and physiological responses of blacktip reef shark (Carcharhinus melanopterus) neonates to climate change relevant changes in temperature (28 and 31 °C) and carbon dioxide partial pressures (pCO₂; 650 and 1050 µatm) using a fully factorial design. Behavioural assays (lateralisation, activity level) were conducted upon 7–13 days of acclimation, and physiological assays (hypoxia tolerance, oxygen uptake rates, acid–base and haematological status) were …

Identifying Important Juvenile Dusky Shark Habitat In The Northwest Atlantic Ocean Using Acoustic Telemetry And Spatial Modeling, Charles W. Bangley, Tobey H. Curtis, David H. Secor, Robert J. Latour, Matthew B. Ogburn

VIMS Articles

Highly mobile species can be challenging for fisheries management and conservation due to large home ranges combined with dependence on discrete habitat areas where they can be easily targeted or vulnerable to anthropogenic disturbances. Management of the Dusky Shark Carcharhinus obscurus in the northwest Atlantic Ocean has been particularly challenging due to the species' inherent vulnerability to overfishing and poorly understood habitat associations. To better understand habitat associations and seasonal distributions, we combined telemetry and remotely sensed environmental data to spatially model juvenile Dusky Shark presence probability in the northwest Atlantic Ocean. To accomplish this, 22 juvenile Dusky Sharks (107-220 …

Spillover Of Sea Scallops From Rotational Closures In The Mid-Atlantic Bight (United States), Deborah R. Hart, Daphne M. Munroe, Joseph C. Caracappa, Dale Haidvogel, Burton V. Shank, David Rudders, Et Al

VIMS Articles

We examined evidence for larval spillover (increased recruitment outside the closures) of Atlantic sea scallops (Placopecten magellanicus) due to rotational closures in the Mid-Atlantic Bight using a 40-year fisheries survey time series and a larval transport model. Since the first closure of the Hudson Canyon South (HCS) area in 1998, mean recruitment in the two areas directly down-current from this closure, Elephant Trunk (ET) and Delmarva (DMV), increased significantly by factors of about 7 and 2, respectively. Stock–recruit plots indicate that low biomasses in HCS were associated with reduced mean recruitment in ET and DMV. Simulations indicate that …

Improving Production Of The Eastern Oyster Crassostrea Virginica Through Coordination Of Genetic Improvement Programs, Research, And Technology Transfer Activities, Standish K. Allen Jr., Caird Rexroad Iii, Robert Rheault

VIMS Articles

The East Coast Shellfish Growers Association has been actively advocating for continued improvement of breeding infrastructure to support a vibrant and ecologically crucial industry. This white paper acknowledges these efforts and is meant to serve as a paradigm for oyster breeding on the East Coast. The vision is relatively straightforward; however, its execution—like most things—will be fraught with detail and inertia. Yet describing simply the idea without articulating some detail and potential roadblocks would be misleading. Instead, we present a picture of a breeding paradigm as it might play out across the entire range of a species. At this particular …

Are Predator−Prey Model Predictions Supported By Empirical Data? Evidence For A Storm-Driven Shift Toan Alternative Stable State In A Crab−Clam System, Cassandra N. Glaspie, Rochelle D. Seitz, Romuald N. Lipcius

VIMS Articles

A dynamic systems approach can predict steady states in predator−prey interactions,but there are very few examples of predictions from predator−prey models conforming to empirical data. Here, we examined the evidence for the low-density steady state predicted by a Lotka-Volterra model of a crab−clam predator−prey system using data from long-term monitoring, and data from a previously published field survey and field predation experiment. Changepoint analysis of time series data indicate that a shift to low density occurred for the soft-shell clam Mya arenaria in 1972, the year of Tropical Storm Agnes. A possible mechanism for the shift is that Agnes altered …

Bycatch In A Commercial Lobster Fishery: Effects On Two Benthic Predators, Sea Raven And Longhorn Sculpin, Brooke N. Anderson, Amelia M. Weissman, Brett Sweezey, John Mandelman, David Rudders, James A. Sulikowski

VIMS Articles

Studying the species‐specific responses to fishing capture is critical for effective management and conservation of bycatch species given that acute stress incurred from capture and handling may ultimately lead to mortality. While species of low commercial value are often overlooked, having accurate information on the effects of capture on all species is necessary for ecosystem‐based management. Sea Raven (SR) Hemitripterus americanus and Longhorn Sculpin (LHS) Myoxocephalus octodecemspinosus are routinely captured in the commercial American lobster Homarus americanus fishery in the Gulf of Maine, and they are discarded due to low commercial value. Despite a lack of economic value, these predatory …

In The Face Of Climate Change And Exhaustive Exercise: The Physiological Response Of An Important Recreational Fish Species, Daniel P. Crear, Richard Brill, Lauren M.L. Averilla, Sara C. Meakem, Kevin C. Weng

VIMS Articles

Cobia (Rachycentron canadum) support recreational fisheries along the US mid- and south-Atlantic states and have been recently subjected to increased fishing effort, primarily during their spawning season in coastal habitats where increasing temperatures and expanding hypoxic zones are occurring due to climate change. We therefore undertook a study to quantify the physiological abilities of cobia to withstand increases in temperature and hypoxia, including their ability to recover from exhaustive exercise. Respirometry was conducted on cobia from Chesapeake Bay to determine aerobic scope, critical oxygen saturation, ventilation volume and the time to recover from exhaustive exercise under temperature and …

Barriers To Eastern Oyster Aquaculture Expansion In Virginia, Jennifer Beckensteiner, David M. Kaplan, Andrew M. Scheld

VIMS Articles

The eastern oyster once provided major societal and ecosystem benefits, but these benefits have been threatened in recent decades by large declines in oyster harvests. In many areas, recovery of oyster aquaculture faces significant societal opposition and spatial constraints limiting its ability to meet expectations regarding future food needs and provision of ecosystem services. In Virginia, oyster aquaculture has begun to expand, concurrent with an increase in subaqueous leased areas (over 130,000 acres of grounds are currently leased). Though private leases must in theory be used for oyster production, in practice, they can be held for other reasons, such as …

Density-Dependence Mediates The Effects Of Temperature On Growth Of Juvenile Blue Catfish In Nonnative Habitats, Vaskar Nepal, Mary C. Fabrizio

VIMS Articles

The combined effects of conspecific density and climate warming on the vital rates of invasive fish species have not been well studied, but may be important in predicting how successful they will be in the future. We evaluated the effects of temperature and population density on monthly time series of sizes of age-0 Blue Catfish Ictalurus furcatus in the James, York, and Rappahannock River subestuaries (defined here as tidally influenced bodies of water that feed into the Chesapeake Bay) from 1996 to 2017, using growing degree-days (GDDs, °C day) as a measure of thermal time. Our pre- dictive linear mixed-effects …

Movements, Habitat Utilization, And Post-Release Survival Of Cobia (Rachycentron Canadum) That Summer In Virginia Waters Assessed Using Pop-Up Satellite Archival Tags, Douglas R. Jensen, John Graves

VIMS Articles

Cobia (Rachycentron canadum) is a cosmopolitan marine fish that inhabits tropical, sub-tropical, and temperate marine and estuarine waters and supports a major recreational fishery along the U.S. Atlantic and Gulf of Mexico coasts. Recent changes in U.S. cobia management have sparked controversy and highlighted limitations in our understanding of the species’ biology. This study utilized pop-up satellite archival tags (PSATs) to assess the movements, habitat utilization, and post-release survival of cobia that summer in Virginia waters

Contemporary And Future Distributions Of Cobia, Rachycentron Canadum, Dp Crear, Be Watkins, Vs Saba, Je Graves, Dr Jensen, Aj Hobday, Kevin C. Weng

VIMS Articles

Climate change has influenced the distribution and phenology of marine species, globally. However, knowledge of the impacts of climate change is lacking for many species that support valuable recreational fisheries. Cobia (Rachycentron canadum) are the target of an important recreational fishery along the U.S. east coast that is currently the subject of a management controversy regarding allocation and stock structure. Further, the current and probable future distributions of this migratory species are unclear, further complicating decision-making. The objectives of this study are to better define the contemporary distribution of cobia along the U.S. east coast and to project potential shifts …

Sublethal Effects Of Salinity And Temperature On Non-Native Blue Catfish: Implications For Establishment In Atlantic Slope Drainages, Vaskar Nepal, Mary C. Fabrizio

VIMS Articles

The distribution and further range expansion of non-native blue catfish Ictalurus furcatus in coastal waters throughout the United States Atlantic slope depend, in part, on the salinity tolerance of the fish. However, temperature-mediated sublethal effects of increased salinities on blue catfish biology are not yet known. We assessed the effects of salinity and temperature on growth, body condition, body composition and food consumption of juvenile blue catfish in a controlled laboratory experiment. Temperature and salinity had an interactive effect on blue catfish biology, although most fish survived 112 days in salinities up to 10 psu. At salinities 9 psu) likely …

Quantifying The Behavioral And Economic Effects Of Regulatory Change In A Recreational Cobia Fishery, Andrew M. Scheld, William M. Goldsmith, Shelby White, Hamish J. Small, Susanna Musick

VIMS Articles

Fisheries economists typically assume recreational anglers make decisions that maximize individual angler utility, which may depend on fishery and regulatory conditions. Under this framework, changes in regulations can lead to target species substitution by anglers in response to shifts in expectations of trip utility. A stated preference survey was developed and distributed to recreational cobia (Rachycentron canadum) anglers in Virginia to explore the effects of regulatory change on angler decision-making, species targeting, and resulting economic outcomes. The survey included a series of hypothetical choice scenarios, where respondents were asked to select their most preferred alternative after being presented with different …

Invasive Blue Catfish In The Chesapeake Bay Region: A Case Study Of Competing Management Objectives, Mary C. Fabrizio, Vaskar Nepal, Troy D. Tuckey

VIMS Articles

Freshwater fishes have been introduced outside their native range to establish recreational fisheries, but management conflicts arise when such introductions also result in potentially harmful effects on native species. In this case study, we focus on Blue Catfish Ictalurus furcatus, which were introduced in the Chesapeake Bay region and are now considered invasive. In many tidal tributaries, Blue Catfish have increased dramatically in abundance, expanded into high-salinity habitats (up to 21.8 psu), and negatively affected native species, prompting calls for the development of an effective management plan. However, management of this conflict species is complicated by multiple competing objectives, including …

Drivers And Trends In Catch Of Benthic Resources In Chilean Turfs And Surrounding Open Access Areas, Jennifer Beckensteiner, Andrew M. Scheld, Miriam Fernandez, David M. Kaplan

VIMS Articles

Beginning in the 1990’s, Chile implemented an extensive Territorial User Rights for Fisheries (TURFs) network that now comprises nearly 1,000 TURFs. This network provides a rare opportunity to examine spatial and temporal trends in TURF use and impacts on surrounding open access areas (OAAs). In this analysis, landings of keyhole limpet (Fissurella spp.), kelp (Lessonia spp.) and red sea urchin (Loxechinus albus) were used to estimate catch-per-unit effort (CPUEs) and catch-per-unit area (CPUAs) indices inside and outside TURFs by fishing cove. For these species, CPUEs and CPUAs in 2015 were significantly higher inside TURFs. However, temporal trends analyzed with a …

Selectivity Of Two Commercial Dredges Fished In The Northwest Atlantic Sea Scallop Fishery, Sally Roman, David Rudders

VIMS Articles

Size selectivity curves were estimated for two commercial dredge configurations used in the United States Atlantic sea scallop (Placopecten magellanicus) fishery. Traditionally, the New Bedford Style dredge (New Bedford dredge) has been used by the commercial fleet; however, since 2013, the Coonamessett Farm Turtle Deflector Dredge (turtle dredge) has been required seasonally in the Mid-Atlantic region to minimize the capture of sea turtles. This analysis provides estimates of selectivity and relative efficiency for the turtle dredge and the New Bedford dredge. Selectivity information for the turtle dredge is currently unknown, and selectivity for the New Bedford dredge was originally assessed …

A Conservation Palaeobiological Perspective On Chesapeake Bay Oysters, Rowan Lockwood, Roger L. Mann

VIMS Articles

The eastern oyster plays a vital role in estuarine habitats, acting as an ecosystem engineer and improving water quality. Populations of Chesapeake Bay oysters have declined precipitously in recent decades. The fossil record, which preserves 500 000 years of once-thriving reefs, provides a unique opportunity to study pristine reefs to establish a possible baseline for mitigation. For this study, over 900 fossil oysters were examined from three Pleistocene localities in the Chesapeake region. Data on oyster shell lengths, lifespans and population density were assessed. Comparisons to modern Crassostrea virginica, sampled from monitoring surveys of similar environments, reveal that fossil oysters …

High Salinity Tolerance Of Invasive Blue Catfish Suggests Potential For Further Range Expansion In The Chesapeake Bay Region, Vaskar Nepal, Mary C. Fabrizio

VIMS Articles

In estuaries, salinity is believed to limit the colonization of brackish water habitats by freshwater species. Blue catfish Ictalurus furcatus, recognized as a freshwater species, is an invasive species in tidal rivers of the Chesapeake Bay. Salinity tolerance of this species, though likely to determine its potential range expansion and dispersal in estuarine habitats, is not well-known. To address this issue, we subjected blue catfish to a short-term salinity tolerance experiment and found that this species tolerates salinities higher than most freshwater fishes and that larger blue catfish tolerate elevated salinities for longer periods compared with smaller individuals. Our …

Comparisons Of Mean Length-Based Mortality Estimators And Age-Structured Models For Six Southeastern Us Stocks, Quang C. Huynh, Nancie J. Cummings, John M. Hoenig

VIMS Articles

Length-based mortality estimators have been developed as alternative assessment methods for data-limited stocks. We compared mortality estimates from three methodologically related mean length-based methods to those from an age-structured model (ASM). We estimated fishing mortality and determined overfishing status, i.e. if F/F_MSY > 1, for six stocks which support important recreational and commercial fisheries in the southeastern United States. The similarities in historical fishing mortality between the length-based methods and the most recent assessments varied among the case studies, but the classification of overfishing status in the terminal year did not differ based on the choice of model …

Temporal, Spatial, And Biological Variation Of Nematode Epidemiology In American Eels, Zt Warshafsky, Troy D. Tuckey, Wk Vogelbein, Rj Latour, Ar Wargo

VIMS Articles

This is the accepted manuscript version of the article.

American eels (Anguilla rostrata) are infected by the non-native parasitic nematode Anguillicoloides crassus, which can cause severe swim bladder damage. We investigated epidemiology of A. crassus to better understand its population-level effects on American eels. Nematode prevalence, abundance, and intensity and swim bladder damage were quantified in glass eels, elvers, and yellow eels from the lower Chesapeake Bay and related to season of capture, river system, and total length. Age-variant force-of-infection and disease-associated mortality were estimated using a three-state irreversible disease model, which assumes recovery is not possible. Results showed glass …