Marine Biology Commons^™

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 …

Dichotomous Keys: An Essential Tool For Fish Detectives, Jackson Martinez

Reports

Grades: 6-8 Subjects: Life Science | Biology

How do scientists identify an unknown fish?

In this activity, students will utilize a dichotomous key to identify unknown fishes from the Chesapeake Bay and will then characterize their trophic levels based on feeding preferences and adaptations. Students will gain an understanding of organism classification, trophic level interactions, and how fishes may play different trophic roles throughout their lives.

A Data Repository For Minimal Effects Of Oyster Aquaculture On Water Quality: Examples From Southern Chesapeake Bay, Jessica Turner, Grace M. Massey, M. Lisa Kellogg, Carl Friedrichs

Data

The objective of this study was to quantify the effects of oyster aquaculture on water quality, sediment quality, and hydrodynamics at select sites in southern Chesapeake Bay. To this end, information was gathered over the course of approximately one year from February 2017 to October 2017 at four operating commercial farms. Farms were sampled during spring, summer, and fall seasons during times of oyster filtration activity when temperatures were greater than 10^oC. Aquaculture sites differed in environmental setting, in terms of their exposure to waves and resulting sediment characteristics. Sites had mesohaline salinities (ranging from 15-22 psu) and …

Tracking Decadal Changes In Striped Bass Recruitment: A Calibration Study Of Seine Surveys In Chesapeake Bay, Mary C. Fabrizio, Troy D. Tuckey, Olivia M. Philips, Brian K. Gallagher

Reports

In this study we estimated calibration factors necessary to maintain the long‐term integrity of the juvenile striped bass surveys in the Chesapeake Bay region. These surveys provide annual indices of recruitment (estimated as juvenile fish abundance in summer) and are used by fisheries managers in Virginia and Maryland to inform adjustments of annual harvest limits for striped bass from the commercial and recreational fisheries in Chesapeake Bay. During the multi‐decadal history of the survey, a potentially influential change occurred: VIMS deployed a net (the VA net) with a mesh material that differed from the standard net that MD DNR continued …

Beyond Zar: The Use And Abuse Of Classification Statistics For Otolith Chemistry, C. M. Jones, M. Palmers, J. J. Schaffler

OES Faculty Publications

Classification method performance was evaluated using otolith chemistry of juvenile Atlantic menhaden Brevoortia tyrannus when assumptions of data normality were met and were violated. Four methods were tested [linear discriminant function analysis (LDFA), quadratic discriminant function analysis (QDFA), random forest (RF) and artificial neural networks (ANN)] using computer simulation to determine their performance when variable-group means ranged from small to large and their performance under conditions of typical skewness to double the amount of skewness typically observed. Using the kappa index, the parametric methods performed best after applying appropriate data transformation, gaining 2% better performance with LDFA performing slightly better …

Chesapeake Aquaculture, Garth Woodruff

Faculty Publications

No abstract provided.

Biodiversity And You., Garth Woodruff

Faculty Publications

No abstract provided.

The Dilemma Of Derelict Gear: Datasets, Andrew M. Scheld, Donna M. Bilkovic, Kirk J. Havens

Data

No abstract provided.

How Do Shellfisheries Influence Genetic Connectivity In Metapopulations? A Modeling Study Examining The Role Of Lower Size Limits In Oyster Fisheries, Daphne M. Munroe, Eileen E. Hofmann, Eric N. Powell, John M. Klinck

CCPO Publications

Fisheries can potentially alter evolutionary processes such as genetic connectivity and lead to genotypic changes in stocks. Using an individual-based metapopulation genetics model, we examined the possible influence of oyster (Crassostrea virginica) fisheries on genetic connectivity. We simulated a range of realistic fishing pressures, with and without a minimum size limit (limit = 63.5 mm), over a range of fishing scenarios including single-area and stock-wide fisheries. Movement of a neutral marker gene provided an indicator of gene transfer between populations. Simulations showed that fishing may alter genetic connectivity. Increasing fishing pressure tended to decrease potential for fished populations …

Population Dynamics Of Sheepshead (Archosargus Probatocephalus; Walbaum 1792) In The Chesapeake Bay Region: A Comparison To Other Areas And An Assessment Of Their Current Status, Joseph Charles Ballenger

OES Theses and Dissertations

Sheepshead recently have seen an increase in fishing pressure in Virginian waters of the Chesapeake Bay. This increase in fishing pressure has led to demands to install effective management measures to protect the fishery. However, no study regarding the population dynamics, and thus potential yield, of sheepshead has been conducted north of Cape Hatteras. We addressed the need for information regarding the population dynamics of Chesapeake Bay sheepshead by investigating their age distribution, growth rate and reproductive biology. We used this information to construct yield-per-recruit models, which local management agencies may use in the formation of scientifically based management measures. …

Evaluating Methods For Optimizing Classification Success From Otolith Tracers For Spotted Seatrout (Cynoscion Nebulosus) In The Chesapeake Bay, Stacy Kavita Beharry

OES Theses and Dissertations

Identifying the natal sources of fish is an important step in understanding its population dynamics. Adult recruits are often sourced from multiple nursery areas, with good quality locations contributing disproportionately more fish to the adult stock. Because population persistence is strongly influenced by nursery habitat, methods that correctly identify the source of recruits are necessary for effective management. Within the last decade, otolith chemistry signatures have been increasingly used as a natural marker to delineate fish from a mixture of nursery sources. Despite the widespread use of otolith trace element and stable isotope ratios as habitat markers, the statistical approaches …

Patterns Of Larval Atlantic Croaker Ingress Into Chesapeake Bay, Usa, Jason J. Schaffler, Christian S. Reiss, Cynthia M. Jones

OES Faculty Publications

We compared ingress patterns of Atlantic croaker Micropogonias undulatus larvae into Chesapeake Bay, USA, with published ingress patterns through barrier island inlets, the accepted model for larval fish ingress. This model asserts that larvae ingress on night flood tides at the flooddominated side of the inlet and at all depths. At the Chesapeake Bay mouth and in the adjacent coastal waters, we compared the distribution of abundance, size, age, and growth rates of croaker prior to ingress, In contrast to the barrier island inlet model, croaker larvae were more abundant at depth than closer to the surface regardless of location. …

Substituting Otoliths For Chemical Analyses: Does Sagitta = Lapillus?, Nathan G. Smith, Cynthia M. Jones

OES Faculty Publications

Chemical analysis of fish otoliths has become an important technique in fisheries science with widespread applications. Most research up to this point has focused predominantly on sagittal otoliths, but the underlying assumptions may also apply to lapilli. The goal of this study was to determine whether lapilli and sagittae have the same otolith chemistry and whether one can be substituted for the other for solution-based chemical analysis in wild-captured fish. We compared the stable isotope chemistry (δ13C and δ18O) of paired sagittae and lapilli of juvenile spotted seatrout Cynoscion nebulosus collected from Chesapeake Bay seagrass beds in 2002. …

Biophysical Mechanisms Of Larval Fish Ingress Into Chesapeake Bay, Jonathan A. Hare, Simon Thorrold, Harvey Walsh, Christian Reiss, Arnoldo Valle-Levinson, Cynthia Jones

OES Faculty Publications

Selective tidal stream transport is hypothesized as a dominant mechanism by which larvae of marine animals move through estuarine openings. For larvae moving from the shelf to estuarine habitats, selective tidal stream transport proposes that larvae are higher in the water column during flood tide and lower in the water column during ebb tide. Although a number of studies conclude that selective tidal stream transport is the mechanism responsible for larval ingress, few studies consider alternative mechanisms or consider passive explanations for tidal patterns in larval distributions. We examined the biophysical mechanisms responsible for larval ingress into Chesapeake Bay using …

Reproduction Of Black Drum, Pogonias Cromis, From The Chesapeake Bay Region, Brian K. Wells, Cynthia M. Jones

Virginia Journal of Science

Ovaries of black drum, Pogonias cromis, collected from the Chesapeake Bay region in 1992, were used to describe reproductive strategy and fecundity. Histological examination showed that black drum spawn in the Chesapeake Bay region from April through early June. Distributions of oocyte diameter showed distinct oocyte-developmental groups indicating that Chesapeake Bay black drum are group-synchronous batch spawners. Female black drum are extremely fecund ranging from 414,000 to 3,736,000 hydrated oocytes (mean = 1,389,000) per batch with a spawning periodicity of 3.8 days. Estimates of spawning strategy, spawning periodicity, and batch fecundity for black drum from the Chesapeake Bay region …

Growth Rate Variability And Lipofuscin Accumulation Rates In The Blue Crab Callinectes Sapidus, Se-Jong Ju, David H. Secor, H. Rodger Harvey

OES Faculty Publications

To better understand growth and age-pigment (lipofuscin) accumulation rates of the blue crab Callinectes sapidus under natural conditions, juveniles (33 to 94 mm carapace width) were reared in outdoor ponds for over 1 yr. Growth rates, measured by carapace width, during summer and fall exceeded all those reported in the literature; the initial carapace width of 59 ± 14 mm (mean ± SD) increased to 164 ± 15 mm within a 3 mo period. No growth occurred during winter months (November to April) at low water temperatures. Growth rates of crabs in ponds were substantially higher (von Bertalanffy growth parameter …

Description, Distribution, And Abundance Of The Blue Crab, Callinectes Sapidus (Rathbun), Spawning Stock Of The Lower Chesapeake Bay, Patrick John Geer

OES Theses and Dissertations

The lower Chesapeake Bay spawning stock of the blue crab, Callinectes sapidus, (Rathbun), is examined for seven years (1986 - 1992) in an attempt to better understand stock behavior. Three methods of post-stratification are used to describe the distribution and movement of the population over time. The three methods, density strata, geographic zones, and depth strata, did well in explaining movements of the population, indicating a trend of increased concentration of blue crabs near the eastern Bay late in the spawning season - October. The data suggest a bimodal period of spawning and a trimodal period of abundance. The …

Age, Growth, And Mortality Of Atlantic Croaker, Micropogonias Undulatus, In The Chesapeake Bay Region, With A Discussion Of Apparent Geographic Changes In Population Dynamics, Luiz R. Barbieri, Mark E. Chittenden Jr., Cynthia M. Jones

OES Faculty Publications

Atlantic croaker, Micropogonias undulatus, collected from commercial catches in Chesapeake Bay and in Virginia and North Carolina coastal waters during 1988-1991 (n=1,967) were aged from transverse otolith sections. Ages 1-8 were recorded, but eight-year-old fish were rare. Marginal increment analysis showed that for ages 1-7, annuli are formed once a year during the period April-May. Otolith age readings were precise: >99% agreement within and between readers. Observed lengths-at-age were highly variable and growth rate decreased after the first year. Despite the high variability in sizes-at-age, observed lengths for ages 1-7 fit the von Bertalanffy growth model (r2=0.99; n=753) well. …

Age Growth And Reproduction Of Black Drum, Pogonias Cromis, In Virginia, Stephen J. Bobko

Biological Sciences Theses & Dissertations

The black drum, Pogonias cromis, is of great economic importance to the communities of the lower Eastern Shore of Virginia. Fish are sought both commercially and recreationally during their yearly spring spawning run. Although the number of fish caught each year does not rival other exploited species, it is a directed fishery that partially supports many local fishermen, seafood distributors, marinas, motel owners, and restauranteurs.

Black drum were collected during the fall of 1989 and the spring of 1990 to investigate the population dynamics of fish found in Virginia's Chesapeake Bay and surrounding coastal waters. A total of 235 fish …

Effects Of Perkinsus Marinus Infection In The Eastern Oyster, Crassostrea Virginica: I. Susceptibility Of Native And Msx-Resistant Stocks, Eugene Burreson

VIMS Articles

A selective breeding program was implemented to attempt to decrease the disease susceptibility of the eastern oyster, Crassostrea virginica, to Perkinsus marinus. Six oyster strains were spawned and the progeny exposed to Haplosporidium nelsoni (MSX) and P. marinus in the lower Chesapeake Bay. Three strains, a Delaware Bay MSX-resistant strain, a Delaware Bay native strain, and a Mobjack Bay native strain (lower Chesapeake Bay) were exposed for three years (1988-90); three other strains, a separate Delaware Bay MSX-resistant strain, a lower James River native strain (lower Chesapeake Bay) and a susceptible control strain, were exposed for two years (1989-90). …

Effects Of Perkinsus Marinus Infection In The Eastern Oyster, Crassostrea Virginica: Ii. Disease Development And Impact On Growth Rate At Different Salinities, Kennedy T. Paynter, Eugene M. Burreson

VIMS Articles

In order to assess the impact of Perkinsus marinus infection on oyster growth and mortality, oysters were raised in floating rafts at six sites around Chesapeake Bay. The sites were comprised of two low salinity sites (8-10%0), two moderate salinity (12-15%0) sites and two high salinity sites (16-20%0). Oyster growth was monitored biweekly along with various water qualities including temperature and salinity. Condition index was measured monthly and disease diagnosis was perfonned bimonthly. Oyster growth was initially greatest at the high salinity sites but was subsequently retarded by Perkinsus infection at both the moderate and high salinity sites (where the …

Susceptibility Of Diploid And Triploid Pacific Oysters, Crassostrea Gigas (Thunberg, 1793) And Eastern Oysters, Crassostrea Virginica (Gmelin, 1791), To Perkinsus Marinus, Judith A. Meyers, Eugene M. Burreson, Bruce J. Barber, Roger L. Mann

VIMS Articles

The susceptibility of Pacific oysters, Crassostrea gigas, to the oyster parasite Perkinsus marinus was compared with that of eastern oysters, Crassostrea virginica, in two separate experiments. Experiments were conducted in flow-through seawater systems with quarantined effluent. Oysters were challenged by addition of infective P. marinus. In the first experiment, which used only diploid oysters, 40% of C. gigas became infected with P. marinus after 83 days compared to 100% of C. virginica. In the second experiment, which examined susceptibility of diploid and triploid individuals of both species, prevalence was high in all groups after 60 days. In …

Estimates Of Spawning Stock Size Of Blue Crab, Callinectes Sapidus, In Chesapeake Bay, 1986-1987, Cynthia M. Jones, John R. Mcconaugha, Patrick J. Geer, Michael H. Prager

OES Faculty Publications

The 1986 spawning stock exhibited a single abundance peak, increasing from 1.0×105 individuals in early July to 9.3×106 in late July, maintaining high levels throughout the summer, and declining in the fall to 7.4×105 individuals. The 1987 spawning stock showed 2 peaks of abundance. The population reached the lesser peak, 1.0×106 individuals, in late July; the greater peak, 1.5×106, in late August. By late September, the population had declined to 6.5×105 individuals. The peak abundance of the 1987 female spawning stock was only 16% as great as the peak abundance in 1986; the 1987 spawning stock size in 1986. Variability …

Fecundity Of Blue Crab, Callinectes Sapidus, In Chesapeake Bay: Biological, Statistical And Management Considerations, Michael H. Prager, John R. Mcconaugha, Cynthia M. Jones, Patrick J. Geer

OES Faculty Publications

Ovigerous blue crabs were collected from the mouth of Chesapeake Bay during the 1986 and 1987 spawning seasons. Mean carapace width was 14.7 cm; mean fecundity was 3.2×106 eggs. Fecundity was significantly related to carapace width, and did not vary significantly with developmental stage of the eggs. Mean fecundities were 2.6×106 eggs in 1986, and 4.0×106 eggs in 1987. An additive model with year and size effects described the observed fecundities reasonably well, was compact, and was easier to interpret than a multiplicative model. To fit a more general model without year effects, the authors took the mean of 1986 …

The Temporal And Spatial Distribution Of Blue Crab Larvae On The Mid-Atlantic Bight Adjacent To The Chesapeake Bay, 1982-1983, Lyle Michael Varnell

OES Theses and Dissertations

Recruitment processes are important information for the management of commercially and recreationally exploited marine species. Recruitment processes of the Chesapeake Bay's most important commercial and recreational species, the blue crab, are unknown, due in part to the lack of knowledge of the processes directly preceeding recruitment.

The present study was undertaken to investigate and explain the movement and developmental patterns of blue crab larvae while offshore. Interannual and intraseasonal variations of these patterns were also examined.

Sampling occurred from May to November during 1982 and 1983. Larvae were collected at three depths (neuston layer (upper 10 cm), one meter and …

Age And Growth Of The Tautog, Tautoga Onitis (Pisces: Labridae), From Lower Chesapeake Bay And Coastal Waters Of Virginia, E. Brian Hostetter

Biological Sciences Theses & Dissertations

The tautog, Tautoga onitis (Pisces: Labridae), is rapidly gaining popularity in Virginia by anglers, spearfishermen and specialized commercial interests. In Virginia, tautog are seasonally abundant on hard bottom substrates in nearshore (ca. 2-10 m) habitats and inhabit offshore wrecks and reef areas (ca. 10-30 m) year round. Habitat restriction and slow growth of the species coupled with recent technological advances in marine electronics which simplify locating tautog populations by user groups may contribute to overexploitation of tautog within the region.

Tautog were collected over a two year period from the lower Chesapeake Bay and nearshore waters of the Atlantic Ocean …

Timing Of The Blue Crab Fisheries Of Virginia And Its Application To Harvest Management, J. Dale Shively

OES Theses and Dissertations

The timing of a fishery is a quantitative expression of the composite behaviors of harvesters, markets, animals and climatic events. A quantitative description of the timing of the blue crab (Callinectes sapidus) fisheries of Virginia was established using the time density model of Mundy (1979). Blue crab catch statistics supplied by the National Marine Fisheries Service and the Virginia Marine Resource Commission were divided into two fisheries based on gear type; the summer and winter fisheries. Average performance curves were then constructed using average cumulative proportions of catch. Annual yield estimates were also made and timing in five …