Past and Current Chesapeake Bay Fisheries Science Funded Research
Past and current Chesapeake Bay fisheries science projects address topics to help resource managers make informed decisions.
Research funded by the NOAA Chesapeake Bay Office has covered a range of fisheries-related topics over the years. Themes and species funded research have focused on have often been selected in response to information gaps identified by resource managers.
Examining the Movement Ecology and Habitat Utilization of Black Sea Bass (Centroprisitis striata) in the Chesapeake Bay Using Telemetry Techniques
This Coonamessett Farm Foundation project focuses on black sea bass by specifically examining their movement ecology and habitat utilization through the integration of three methods of tagging and telemetry techniques (passive, acoustic, and satellite), the Chesapeake Bay Interpretive Buoy System (CBIBS), and citizen science volunteers from the Ocean Research Project FishFinder program. NOAA provided $149,443.
The Value of Shallow Tributary Habitats of the Upper Chesapeake Bay to the Summer Flounder (Paralichthys dentatus)
The primary goals of this Smithsonian Environmental Research Center project are to quantify the value of shallow tributary habitats of Chesapeake Bay as nursery and foraging habitat for summer flounder and identify key prey species in those habitats across life-history stages. This project uses an integrated approach that combines field surveys, acoustic telemetry, and innovative approaches to gut content and food web analysis (genetic metabarcoding) and leverages the sampling effort to relate diets to assessments of body condition and growth. Comparisons among sampling seasons (summer, early fall, and late fall), and locations are expected to provide insights into the variation in habitat use among seasons, and telemetry data will provide information on the timing and duration of habitat use, connectivity between estuarine and coastal habitats, and interannual site fidelity to Chesapeake Bay. Specific objectives include: 1) documenting habitat use of summer flounder in shallow tributaries of upper Chesapeake Bay; 2) correlating abundance indices with coastwide abundance trends and environmental variability; 3) investigating connectivity between tributary and offshore habitats and site fidelity; and 4) identifying key prey resources in shallow tributary habitats across life-history stages. NOAA provided $233,058.
Characterization of Nursery Habitats Used by Black Sea Bass and Summer Flounder in the Chesapeake Bay and Coastal Lagoons
The major goal of this Virginia Institute of Marine Science project is to assess nursery habitat availability and characteristics for summer flounder and black sea bass in the Chesapeake Bay bayside and seaside areas and subsequently evaluate the influence of habitat type on juvenile fish production. The objectives are threefold: 1) delineate nursery habitats used by black sea bass and summer flounder in the Chesapeake Bay and the coastal lagoons of the Delmarva Peninsula; 2) identify the relationship between annual recruitment and habitat conditions in nursery areas for 1989 to 2018; and 3) evaluate habitat quality in seaside and bayside nursery areas used by black sea bass and summer flounder. NOAA provided $249,458.
Integrative Assessment of the Quality of Shallow Tributary Forage Habitats for Striped Bass in the Chesapeake Bay
This Smithsonian Environmental Research Center project aims to quantify the quality of shallow tributary habitats of Chesapeake Bay as foraging habitat for striped bass and to identify key prey species in those habitats across life-history stages. This project uses an integrated approach that combines traditional and innovative approaches to gut content and food web analysis (morphological analysis and genetic metabarcoding) and leverages the sampling effort to relate diets to assessments of body condition, parasitism/disease, and growth to paint a comprehensive picture of the relative quality of foraging habitats in different regions of the upper Bay. Objectives include: 1) collect striped bass at multiple size classes in five tributary forage habitats during early summer, late summer, and fall; 2) assess age structure, size structure, size at age, body condition, growth rate (young of the year only), and prevalence and intensity of dermal lesions and other macroparasites; and 3) quantify the diet and sources of nutrition, and 4) integrate data to assess habitat quality. NOAA provided $240,011.
Habitat Utilization and Ecosystem Connectivity in the Southern Mid-Atlantic Bight
The goal of this Virginia Institute of Marine Science project is to develop a holistic evaluation of the biotic responses to the realized and projected climate-driven physical changes in the Chesapeake Bay. There are three main objectives of this investigation that underpin the evaluation of these biotic responses, namely: 1) quantify habitat preferences for summer flounder, black sea bass, and an array of other benthic and pelagic fishes, elasmobranchs, and invertebrates in the Chesapeake Bay, the nearshore coastal ocean, and Delaware Bay; 2) evaluate the extent to which environmental conditions in the Chesapeake Bay influence the degree to which these species use the Bay relative to the nearshore coastal ocean; and 3) assess the role of environmental factors within the Bay in driving use of the Chesapeake Bay as compared to Delaware Bay, a more northerly estuary. NOAA provided $179,561.
Quantifying Habitat Suitability for Forage Fishes in the Chesapeake Bay: A Coupled Modeling Approach Using Fishery Surveys and a Hydrodynamic Model
The goals of this Virginia Institute of Marine Science project are to 1) quantify suitable habitat for forage fishes in the Chesapeake Bay on a seasonal and annual basis and 2) assess the relationship between the extent of suitable habitat and annual forage fish abundance. To accomplish this, the project team constructed and validated habitat suitability models for four key forage species: bay anchovy (Anchoa mitchilli), spot (Leiostomus xanthurus), weakfish (Cynoscion regalis), and spotted hake (Urophycis regia). The modeling approach coupled catch data from fishery surveys with estimates of environmental conditions derived from a hydrodynamic model of the Chesapeake Bay and a temperature/dissolved oxygen (DO) model to provide annual and seasonal assessments of the extent of suitable habitats in 2000-2016. These areas of suitable habitat will be visualized using a GIS and annual estimates of suitable habitat extent will be related to annual indices of forage fish abundance to examine relationships between habitats and forage fish production. NOAA provided $248,530.
Trophic Dynamics of Blue Catfish in Maryland
The overall objective of the Smithsonian Institution's proposed work was to quantify the diet of blue catfish in nearshore, shallow waters areas of Maryland’s tributaries. Specifically, researchers investigated how diet varies (1) spatially among four Maryland tributaries (Patuxent, Nanticoke, Susquehanna and Sassafras rivers), (2) temporally across seasons (spring, summer, fall), and (3) ontogenetically with size. This study was intended to fill key information gaps and help local and regional agencies to more effectively manage this established species, predict the impacts of blue catfish on recreationally and commercially important native stocks, and for ecosystem-based fisheries management that rely critically on knowledge about trophic interactions and food web structure. NOAA provided $165,097.
Estimating Population Size and Survival Rates of Blue Catfish in Chesapeake Bay Tributaries
This Virginia Institute of Marine Science project proposed to estimate the abundance of blue catfish in the James River, Virginia, from a multiyear mark‐recapture study. The researchers aimed to capture and tag 100,000 blue catfish with coded wire tags; fish will be captured by electrofishing, tagged, and released. In addition, to better understand movement of individual fish between estuarine and freshwater reaches, a smaller number of fish from oligohaline and mesohaline regions of the James and Potomac Rivers were planned to be tagged with dart tags (by anglers and by researchers). Researchers planned to use Pollock’s robust design model to analyze the tagging data and provide managers with an estimate of population size and movement rates between the areas sampled. NOAA provided $573,757.
Predation by Introduced Blue Catfish as a Potentially Important and Novel Source of Mortality for Selected Fishery Resources in Chesapeake Bay Waters
Objectives of this Virginia Commonwealth University project included:
- Quantifying seasonal and spatial occurrence of selected prey types, representing ecologically and economically important species such as American shad and Atlantic menhaden, in blue catfish diets for major riverine and estuarine habitats, including tidal freshwater and polyhaline reaches of Chesapeake Bay.
- Generating expanded estimates of predation mortality by blue catfish populations on anadromous clupeid fishes, including American shad and blueback herring, for specific river systems in Virginia and Maryland.
- Developing specific management recommendations regarding the current and future impact of blue catfish predation on restoration programs for anadromous fishes in Virginia and Maryland, including tactics to mitigate those impacts where feasible.
NOAA provided $54,126.
Expansion of the Blue Catfish Fishery as a Population Control Strategy: Influence of Ecological Factors on Fish Contaminant Burdens
This Virginia Institute of Marine Science study sought to develop a model that characterizes contaminant levels in blue catfish to better protect human health. Blue catfish from the James, Rappahannock, and Potomac Rivers were examined to evaluate geographical variability in the Chesapeake Bay watershed. Contaminants proposed to by analyzed included mercury, legacy organic pollutants (i.e. PCBs and organochlorine pesticides), and emerging chemicals (i.e. polybrominated flame retardants) that have previously been found to pose risks via consumption of some mid-Atlantic region fish. NOAA provided $91,216.
Characterizing the Growth Dynamics of Blue Catfish in the Chesapeake Bay Watershed
The Virginia Institute of Marine Science intended to document blue catfish growth patterns in several primary tributaries of Chesapeake Bay. These results would aid attempts to quantify the productivity of blue catfish populations and begin to formulate a scientific framework that can facilitate effective management. The objectives of this study were to: (1) develop a master database of existing and newly collected data on the growth of blue catfish in (but not limited to) the James, York, Rappahannock, and Potomac River systems, and (2) analyze those existing and newly collected data to formally describe the growth patterns and dynamics of blue catfish in the aforementioned tributaries of Chesapeake Bay. NOAA provided $45,649.
Estimating Abundance of Atlantic Menhaden in Chesapeake Bay: Comparing and Evaluating Methods and Retrospective Analysis
The University of Maryland Center for Environmental Science addressed the stock monitoring and biological reference point priorities for Atlantic menhaden. Additionally, it undertook a synthetic, retrospective analysis of data on YOY menhaden from the existing Maryland Department of Natural Resources seine-survey data to evaluate factors that contribute to recruitment variability. Successful recruitment of juvenile menhaden was hypothesized to be in part related to growth histories and variability in environmental/ hydrographic conditions during the juvenile production period. Research cruises in spring-summer 2012 were proposed in the Choptank and Patuxent Rivers and the Upper Bay. Midwater trawl, bottom trawl, and seine surveys were planned at the same sites and times. Catches, catches per unit effort, and variability in catches and sizes of menhaden and other pelagic fishes were evaluated. Ages and growth rates of YOY menhaden were estimated from otolith microstructure analysis. Growth rates and models were compared with rates and models from our earlier research. The research sought to evaluate present methods to estimate recruiting abundances of YOY menhaden and provide potential alternatives to improve the methodology. NOAA provided $135,000.
A Retrospective Analysis of Spatial and Temporal Patterns of Growth and Abundance of Juvenile Anadromous Fishes in the Maryland Chesapeake Bay
Under this University of Maryland Center for Environmental Science project, researchers planned a retrospective analysis of long-term monitoring data to develop resource management products. They analyzed length and abundance data collected by the Maryland Department of Natural Resources Juvenile Striped Bass Seine Survey data to compare size, biomass, and growth rates of young-of-the-year striped bass, white perch, yellow perch, and alosines across tributaries and the upper Bay. The survey began in the late 1950s, which allowed detection of temporal trends and comparisons among tributaries through time. Also included in the analysis were water quality, zooplankton, and benthic organism monitoring data collected by the Chesapeake Bay Program since 1984 to compare Maryland’s tributaries and upper Bay in an evaluation of temporal trends in potential productivity with respect to YOY anadromous species. NOAA provided $52,000.
Oyster Reef Ecosystem Services
Integrated Assessment of Oyster Reef Ecosystem Services: Fish and Crustacean Utilization, Secondary Production, and Trophic Linkages
This project is at the Virginia Institute of Marine Science. Using a regression design that encompasses the continuum of reef types in Harris Creek, Maryland, from buried unrestored reefs to those with the greatest oyster biomass, researchers will compare finfish and crustacean utilization of restored oyster reefs to unrestored sites. Specifically, they will sample two sites that have received no restoration (one completely buried in sediments and one with some surface shell but very few or no oysters) and six sites that have been planted with juvenile oysters set on oyster shell and that encompass the broadest possible range of oyster biomass densities in Harris Creek. All eight sites will be sampled during each of five sampling periods distributed throughout year (April, June, August, October, and January) for three years. Researchers will assess abundance, diversity, total length (or carapace width), and biomass of finfish and crustaceans using a combination of baited crab pots, baited fish traps, and gill nets. This combination of sampling gear has been chosen to sample a broad spectrum of organism sizes and feeding habits and to complement NCBO plans for sampling at other sites in the Choptank River complex. Finfish diets will be assessed by examining gut contents of each species during each sampling event. For resident species, secondary production will be estimated using the mean annual biomass of each taxonomic group combined with published production to biomass ratios. Annual rates of nutrient sequestration will be calculated based on secondary production and nutrient composition. NOAA provided $195,046.
Integrated Assessment of Oyster Reef Ecosystem Services: Quantifying Denitrification Rates and Nutrient Fluxes
University of Maryland Center for Environmental Science researchers will carry out measurements of the fluxes of oxygen, nitrogen, and phosphorus in Harris Creek, Maryland, using the ex situ technique we developed to assess fluxes on a restored oyster reef in Choptank River (Kellogg et al. 2013). This work will be a continuation of our NCBO-funded work at Harris Creek in 2014 that will begin in spring 2014. Intact subsections (0.1 m2) of the oyster reef and associated communities will be brought into the laboratory, sealed in stirred microcosms, and a time course of the concentrations of ammonium, nitrate plus nitrite, N2 (denitrification), O2, and soluble reactive P will be used to estimate net fluxes of these biogeochemical components. For samples from shallow, illuminated environments researchers will employ both dark and illuminated incubations. The abundance, biomass, and diversity of the benthic community in each microcosm will determined. Working with our NCBO partners, UMCES will utilize an adaptive management approach to ensure that their experimental design will meet project objectives throughout the three-year time frame of this assessment. Using the data from this project, researchers will determine the increase in the rates of denitrification that occur as oyster reefs mature and assess whether the ecosystem services provided by oyster reef restoration and subsequent development can change the nitrogen balance of a tributary. NOAA provided $219,981.
Integrated Assessment of Oyster Reef Ecosystem Services: Macrofaunal Utilization, Secondary Production, and Nutrient Sequestration
University of Maryland-College Park researchers will estimate the utilization, productivity, and nutrient sequestration capacity of the macrofaunal communities associated with oyster reefs across a range of oyster biomass density. Harris Creek was chosen because of an large-scale ongoing restoration effort in this tributary and the extensive dataset available on the oysters and substratum characteristics in this tributary. For this project, researchers will select eight reef sites including six restored reef sites, one “substrate addition” control, and one “seed only” control = unrestored site suitable for planting spat-on-shell directly on the bottom. At each site one month prior to each of five annual sampling periods, divers will fill four wire mesh baskets (0.1m2 surface area x 15 cm depth) with material from the site and embed them so that the surface is flush with the surrounding substratum (4 baskets x 8 sites x 5 sampling period = 160 samples/yr). Five times each year, divers will collect baskets and return them to the laboratory where the abundance, diversity, and biomass of all macrofauna will be quantified. Using these data, secondary production rates will be calculated for major taxonomic groupings at each site. Secondary production rates combined with existing and new data on the nitrogen and phosphorus content of oyster reef macrofauna will be used to estimate rates of nitrogen and phosphorus sequestration in the tissues of oyster reef macrofauna in relation to oyster biomass density and other easily measured oyster reef characteristics. NOAA provided $188,808.
Application of Dual-Frequency Imaging Sonar to the Study of Oyster Reef Ecosystem Services
Smithsonian Environmental Research Center researchers will use two DIDSON imaging sonar units ($150,000 total value) to evaluate trap encounter and capture efficiency rates of ORES sampling gears in Maryland (Choptank River Complex). This work will enhance the interpretation of data collected by NCBO’s ORES project and related NCBO-funded projects by providing correction factors for sampling gear bias. The project will also use DIDSON to conduct trap-independent fish and crab abundance surveys in restored and control sites in Maryland (Choptank River Complex) and Virginia. DIDSON surveys will be especially useful for estimating the abundance of larger fish (e.g. striped bass, cownose rays, American eels) that may be least effectively sampled by traditional sampling methods. In Virginia, DIDSON and video surveys will be conducted simultaneously in collaboration with VIMS to evaluate the comparability of methods. This project builds on and enhances the ORES and related projects and will improve the data for quantifying the ecosystem services of large-scale oyster restoration in Chesapeake Bay. NOAA provided $185,303.
Ecosystem Services of Restored Oyster Reefs in Lower Chesapeake Bay
This Virginia Institute of Marine Science project seeks to determine finfish and blue crab utilization of oyster reefs in relation to reef characteristics, environmental conditions, geographic location, and prey availability in the Great Wicomico, Lynnhaven, and Lafayette Rivers of the lower western shore of Chesapeake Bay. Restoration reefs in these systems encompass the full range of reef types in the lower Bay, including high-relief, low-relief, natural, and harvest ground reefs, as well as unrestored bottom. Specific objectives are to (i) quantify finfish and blue crab use of differing oyster reefs using underwater video (baited and unbaited) and baited trap surveys, (ii) quantify benthic prey availability at the reefs, (iii) assess bias of baited traps in estimating use of reefs by finfish and blue crabs, (iv) characterize the diet of finfish and blue crab at the reefs, and (v) quantify variability in the use of oyster reefs by finfish and blue crabs as a function of reef height, reef type, geographic location, and prey availability. The project is multifaceted and collaborative in that it uses information from (a) bottom side-scan surveys by NOAA and the Army Corps of Engineers, Norfolk District (ACEN), (b) monitoring surveys by VIMS, VMRC and the Chesapeake Bay Foundation, (c) upcoming reef manipulations by ACEN, (d) hydrographic information by VIMS and NOAA, and (e) volunteer assistance from citizen groups such as Lynnhaven River Now. NOAA provided $199,735.
Natural Engineers in Ecosystem Restoration: Modeling Oyster Reef Impacts on Particle Removal and Nutrient Cycling
University of Maryland Center for Environmental Science researchers will work on improvements to an existing advection-diffusion model of particle capture on an oyster reef to incorporate processes related to nitrogen cycling such as denitrification, N remineralization, links to primary production above the reef, and oyster bioenergetics. It is envisioned that this modeling effort will be a means to integrate the biogeochemical and reef morphological studies that have been ongoing in the Choptank River estuary. The model will be used to explore the large-scale implications of changed N remineralization rates and denitrification measured by Kellogg, Cornwell, et al., with other efforts to describe the fine-scale topographical heterogeneity of reef structure, density, and resultant rugosity across the reef surface. Model output will provide quantitative predictions of ecosystem services related to N removal and biomass production in response to measures of restoration projects such as reef size and oyster planting densities. These estimates can be compared with ecosystem model output that does not include restored oysters to evaluate the role of these ecosystem engineers in mediating water quality in the Chesapeake Bay. Participatory modeling efforts will engage the end-user community from the beginning of the project to insure the development of a useful and practical numerical modeling tool. NOAA provided $215,061.
Pathways to Production: An Assessment of Fishery Responses to Oyster Reef Restoration and the Trophic Pathways that Link the Resource to the Reef
This research Virginia Commonwealth University project is designed to quantify the colonization and use of restored oyster reef habitats by economically and ecologically important fish species in the Piankatank River, Virginia. The unique combination of established reefs (greater than eight years postconstruction) and ‘before’ areas to be developed (2015 reef construction) will allow for a BACI (Before-After, Control-Impact) design to quantify how the fish community responds temporally and spatially to habitat manipulation and enhancement from unstructured area to structured reef, and later to structured/biogenic reef as oysters colonize. Researchers will also follow immigration/emigration dynamics of fishes from nearby reefs to resolve the current Attraction-Production debate about the role of restored reefs (Lindberg 1997, Lowery et al. 2014; Pierson and Eggleston 2014). The integration of hydroacoustics, to better quantify fish distribution, with diet and stable isotope analyses, to estimate energy pathways and food sources, addresses some of the inherent sampling bias of previous studies and affords researchers the opportunity to better quantify the oyster reef contribution to fishery resource productivity (economically and ecologically important species) in the Piankatank River, Virginia. NOAA provided $107,848.
Oysters and Clams
A Bay‐Wide Approach to Oyster Stock Assessment, Estimates of Vital Rates and Disease Status of the Eastern Oyster Crassostrea virginica in the Chesapeake Bay
This project, led by the Virginia Institute of Marine Science, originally sought to design, implement, and complete an oyster stock assessment that, using cross-calibrated methods, allows a statistically defensible estimate of the Bay-wide population, location-specific growth rate and disease status, age specific estimates of natural (M) and harvest (F) mortalities, and the vital measurements required to build estuary-specific and Bay-wide shell substrate budgets. Ultimately, this project focused on specific Terms of Reference that were developed with input from the Chesapeake Bay Program's Fisheries Goal Implementation Team. NOAA provided $329,942.
Scaling Ecosystem Services to Reef Development: Effects of Oyster Density on Nitrogen Removal and Reef Community Structure
The overarching goal of this project, led by the Virginia Institute of Marine Science, was to develop a tool for estimating the ecosystem services provided by restored oyster reefs based on easily measured structural parameters. To achieve this goal, researchers used a manipulative experiment and science-based monitoring to quantify relationships between structural and functional habitat characteristics on replicate reefs of differing oyster density constructed both in Onancock Creek, Virginia, and in The Nature Conservancy’s Virginia Coast Reserve within the Hillcrest Oyster Sanctuary. The experimental design and sampling methods used at the two sites were kept as similar as possible to allow for direct comparisons between the two sites. NOAA provided $170,230.
Influence of Oyster Reef Elevation on the Health of Crassostrea virginica
The overall goal of this Virginia Institute of Marine Science project was to generate sound scientific data that either support or refute the assertion that oyster reef architecture influences oyster health, which has not been satisfactorily addressed by previous work. Objectives were: (1) To determine the influence of position on an oyster reef on dermo disease in Crassostrea virginica, (2) to determine the influence of position on an oyster reef on MSX disease in Crassostrea virginica, and (3) to communicate results to stakeholders through the Virginia Sea Grant Marine Advisory Program and the VIMS Shellfish Pathology Laboratory website. NOAA provided $45,825.
Development, Validation, and Application of Molecular Detection Tools for a Virus Infecting Mya arenaria Soft-shell Clams in Chesapeake Bay, for Evaluations of Disease Pathology, Virus Transmission, and Disease Distribution
The overall objective of Maryland Department of Natural Resources' proposed effort was to expand the suite of available assays for diseases of Chesapeake Bay clams to enable comprehensive evaluations of population-level effects of several prevalent clam diseases through development, validation, and application of novel assays for the GENH virus disease. This was proposed to occur over two years:
- Year 1. Develop and validate quantitative molecular-genetic tools for detection and quantification of virus pathogen particles in Mya arenaria clam host tissues, tissues of potential vector animals, and in environmental water and sediment samples.
- Year 2. Use validated molecular-genetic tools to determine the geographic and historic-temporal ranges of virus infections among Mya arenaria clams in Chesapeake Bay, and to evaluate the seasonality and dynamics of environmental virus dispersal and disease transmission events.
NOAA provided $84,843.
Population Decline and Restoration of Soft-Shell Clams in Chesapeake Bay: Role of Predation, Habitat, Disease, and Environmental Factors
This Virginia Institute of Marine Science project aimed to examine the causes of the decline in soft-shell clam, Mya arenaria, populations in Chesapeake Bay. The population of M. arenaria in Chesapeake Bay has been declining for several years with a severe decline in the 1990s to record low levels that have been sustained to the present. The population decline is likely due to multiple factors including: recruitment, predation, habitat loss, disease, and overfishing. This research addressed influential factors sequentially, focusing first on predation issues, and subsequently on habitat, environmental factors, and disease. It’s known that recruitment of Mya in certain systems within Chesapeake Bay has continued to be high, yet survival is low in all but those habitats with sufficient structure to protect clams from predation. It’s also known that disease may also be an important factor in population dynamics, particularly in recent years, as work has shown that Perkinsus has reached epidemic levels in Mya. A diverse team of investigators was assembled, with expertise in bivalve ecology, predator-prey, and host-parasite interactions, to address the causes of Mya population decline and make recommendations for successful soft-shell clam restoration. NOAA provided $179,053.
Oyster-Planting Protocols to Deter Losses to Cownose Ray Predation
The Virginia Institute of Marine Science's project focused on the value of shell overlays to oyster plantings as a ray predator deterrence mechanism. This was an academic/government/industry/non-profit collaboration wherein all parties began and ended the project with a singular commitment to stewardship of the Chesapeake Bay oyster resource for both ecological and economic purposes. The project addresses a critical issue, the potential loss of oysters to predation by cownose rays, in a controlled experimental design but at a scale commensurate with industry practices and large‐scale restoration efforts. NOAA provided $156,297.
Discrimination of Cownose Ray, Rhinoptera bonasus, Stocks Based on Microsatellite DNA Markers
The Virginia Institute of Marine Science's objective for the project was to develop and use microsatellite DNA markers to discriminate stocks of the cownose ray, Rhinoptera bonasus. The specific objectives that were approved were to collect neonate and/or pregnant female cownose rays from the Chesapeake Bay and the Gulf of Mexico; create a suite of molecular markers specific to cownose rays; screen these new markers for reliability and variability in the cownose ray; and analyze cownose ray samples collected from the nursery groups in the Chesapeake bay and Gulf of Mexico to look for evidence of stock structure and to get baseline estimates of genetic diversity. NOAA provided $45,523.
Life History, Trophic Ecology, and Prey Handling by Cownose Rays from the Chesapeake Bay
This Virginia Institute of Marine Science study was designed to document the age, growth, and predation for cownose ray, focusing on the population that uses the Chesapeake Bay for pupping and mating during summer months. NOAA provided $203,384.
Evaluating Population-Level Impacts of Sperm Limitation on the Chesapeake Blue Crab Stock
The proposed Smithsonian Institution work had two main objectives: (1) quantify sperm stores of mature female blue crabs in the lower Bay spawning stock across a single reproductive season and (2) construct a model to assess the current impact of sperm limitation on reproductive success of the blue crabs in Chesapeake Bay. Project objectives and outcomes would directly support the NCBO mission to support science-based management, assess the status of coastal living resources, and evaluate the effectiveness of recent management for the blue crab in Chesapeake Bay, which is now centered on the conservation of the female spawning stock. NOAA provided $66,513.
Effects of Changing Population Density on Blue Crab Reproduction
The overall objective of this Old Dominion University Research Foundation study was to examine the effects of harvest pressure on blue crab reproductive effort. Previous results for this population found: 1) a significant relationship between crab abundance and reproductive output and 2) the majority of females (>80%) mate with multiple males. In 2008-09, new management regulations significantly reduced harvest pressure resulting in increased crab abundance and increased reproductive investment in 2010. The project examined reproductive output for 2011 to determine if there was a continued increase. Using previously identified microsatellite DNA markers, individual broods were examined for multiple paternity. Evaluating the paternity of offspring in a single brood would allow researchers to determine how stored sperm from multiple males is utilized by females. This would also provide information regarding genetic diversity of the population, and overall genetic health. Reevaluating the reproductive effort of this population in 2011 would provide insight into population recovery and supply managers with essential information for future regulation of the fishery. NOAA provided $95,816.