Marine Biology Commons^™

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 …

Summer Vertical Phytoplankton Distribution In The Lower Chesapeake Bay, Mollie Jill Weinstein

Biological Sciences Theses & Dissertations

Autotrophic picoplankton and phytoplankton composite samples were collected from the surface, pycnocline, and bottom water layers at three stations in the lower Chesapeake Bay between June and September 1993. Using light microscopy a total of 170 phytoplankton taxa were identified. Utilizing epifluorescent microscopy, the picoplankton taxa were distinguished by size, representing species with cells less than 2 microns. Diatoms were the dominant taxa during this period, with lesser representation by the other phytoplankton components. Within the picoplankton category, cyanobacteria were dominant. Statistical analyses of the data indicated the vertical composition and abundance of the phytoplankton was not significantly different over …

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 …

Can An Optical Plankton Counter Produce Reasonable Estimates Of Zooplankton Abundance And Biovolume In Water With High Detritus?, X. Zhang, M. Roman, A. Sanford, H. Adolf, C. Lascara, R. Burgett

CCPO Publications

The Optical Plankton Counter (OPC) has been used in oceanic and fresh waters to estimate zooplankton abundance and biovolume. However, it is not clear whether the OPC can produce accurate estimates of zooplankton abundance and biovolume in waters with high detritus. In order to test the capability of the OPC to estimate zooplankton abundance and biovolume in Chesapeake Bay, two sets of laboratory experiments were conducted using water with high detritus concentrations collected from the upper Choptank estuary of Chesapeake Bay and laboratory cultured Artemia. Our results suggest that the OPC is able to produce accurate estimates of zooplankton biovolume …

Estuarine Relationships Between Zooplankton Community Structure And Trophic Gradients, Gyung Soo Park, Harold G. Marshall

Biological Sciences Faculty Publications

Zooplankton and water quality parameters were investigated at eight mesohaline stations in the lower Chesapeake Bay and Elizabeth River from January through December 1994 to identify the changes of zooplankton community structure with increased eutrophication. The total micro- and mesozooplankton biomass decreased with the increase of eutrophication. However, the relative proportion of microzooplankton increased with increased eutrophication. Within highly eutrophied waters, the small oligotrichs (m) and rotifers dominated the total zooplankton biomass (as carbon). However, tintinnids, copepod nauplii and mesozooplankton significantly decreased with the increase of eutrophication. These patterns were consistent throughout the seasons and had significant relationships statistically. These …

Use Of Extractable Lipofuscin For Age Determination Of Blue Crab Callinectes Sapidus, Se-Jong Ju, David H. Secor, H. Rodger Harvey

OES Faculty Publications

The blue crab Callinectes sapidus is an economically and ecologically important species in many temperate estuaries, yet stock assessments have been limited to length-based methods for demographic analyses. We evaluated the potential of age pigments (lipofuscins) sequestered in neural tissue of eye-stalks and brains to estimate the age of blue crabs collected from Chesapeake Bay and Chincoteague Bay. The rate of lipofuscin accumulation was determined using crabs of known age reared in the laboratory. Age pigments were extracted from neural tissues (eye-stalk or brain), quantified, and normalized to protein content to allow comparisons across tissue types and crab sizes. Field-collected …

Small-Scale Settlement Patterns Of The Oyster Crassostrea Virginica On A Constructed Intertidal Reef, Ian K. Bartol, Roger Mann

Biological Sciences Faculty Publications

The construction of three-dimensional, intertidal reefs resembling those widely present during colonial times in the Chesapeake Bay, but now absent due to years of overharvesting, may provide a more ecologically advantageous environment for oyster settlement and subsequent survival than present subtidal, two-dimensional habitats. We examined settlement processes on a constructed, 210 x 30 m intertidal reef composed of oyster shell. The reef was destructively and non-destructively sampled weekly throughout the summer and fall at tidal heights ranging from 30 cm above to 90 cm below mean low water (MLW) and at two substrate levels (reef surface and 10 cm below …

Zooplankton Community Dynamics In The Elizabeth River, Virginia, William C. Sharp

Biological Sciences Theses & Dissertations

Zooplankton community structure and dynamics were studied over a 12 month period in the Elizabeth River, an industrially polluted tidal river in the Chesapeake Bay estuarine system. An additional site in this estuary (Hampton Roads) was sampled for comparative purposes. Multivariate analysis indicated five distinct temporal groups occurred during the year, but there were no significant differences in spatial composition within the river. Maximum zooplankton concentrations were observed in July and lowest abundances were observed in February, March, and November. Copepods, especially Acartia species, were the most abundant components of the zooplankton community, comprising 67 to 93% of the total …

Assessment Of Genetic Diversity Of Seagrass Populations Using Dna Fingerprinting: Implications For Population Stability And Management, Randall S. Alberte, Gregory K. Suba, Gabriele Procaccini, Richard C. Zimmerman, Steven R. Fain

OES Faculty Publications

Populations of the temperate seagrass, Zostera marina L. (eelgrass), often exist as discontinuous beds in estuaries, harbors, and bays where they can reproduce sexually or vegetatively through clonal propagation. We examined the genetic structure of three geographically and morphologically distinct populations from central California (Elkhorn Slough, Tomales Bay, and Del Monte Beach), using multilocus restriction fragment length polymorphisms (DNA fingerprints). Within-population genetic similarity (S_w) values for the three eelgrass populations ranged from 0.44 to 0.68. The Tomales Bay population located in an undisturbed, littoral site possessed a within-population genetic similarity (S_w = 0.44) that was significantly lower …

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. …

A Multivariate Characterization Of Assemblages Of Planktonic Mysids Decapods And Sergestids In The Chesapeake Bay Mouth Area, John Charles Seibel

Biological Sciences Theses & Dissertations

This study is the first to focus on the assemblages of the planktonic mysids, decapods, and sergestids found in the lower Chesapeake Bay. The assemblages of these organisms in the lower Chesapeake Bay and nearby shelf were characterized using three different statistical approaches, and the methods used were evaluated for their effectiveness at delineating ecologically meaningful assemblages. Three stations were sampled across the Chesapeake mouth and one offshore, with oblique and neuston net tows. Twenty-seven larval stages, representing at least 23 species, were found in sufficient numbers to be analyzed statistically. The statistical approaches were each based upon a different …

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 …

The Study Of Natural Product(S) From Opsanus Tau (Linnaeus), The Oyster Toadfish, Miki Taira

Chemistry & Biochemistry Theses & Dissertations

Opsanus tau (Linnaeus), the Oyster toadfish, commonly inhabits the Chesapeake Bay. The Oyster toadfish has been categorized as a venomous and/or ichthyotoxic fish; however, chemical studies to substantiate these claims have not been forthcoming.

The oyster toadfish has dorsal and opercular spines which are believed to secrete a venom(s). Based on our findings, the oyster toadfish does not secrete venom(s) from these spines.

The oyster toadfish secretes large amounts of a mucus when it is irritated. 3-Octanone was believed to be the major ichthyotoxic component of the mucus from the oyster toadfish. Based on our investigation, 3-octanone is present only …

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 …

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 …

Picoplankton/Phytoplankton Dynamics In Hampton Roads, Virginia, Leslie E. Dorworth

OES Theses and Dissertations

The biomass distribution of the three main size components of the phytoplankton (net, nano, and picoplankton) was examined in the lower Chesapeake Bay. Work was done at two stations during the spring and neap tidal cycles when freshwater flow into the bay was at its seasonal minimum and maximum. Emphasis was placed on how the picoplankton ( < 2.0 μm, > 0.2 μm) reacted during the sampling period.

Picoplankton made up approximately 13% of the total biomass, during the observed time period, at the more oceanic station. The picoplankton fraction contributed up to 16% of the total biomass at the estuarine station. From this …

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 …

A Biochemical And Genetic Analysis Of The American Shad Alosa Sapidissima Migrating Into The Chesapeake Bay, Edward Norbert Sismour

Biological Sciences Theses & Dissertations

Seven enzymes extracted from heart and liver tissues of American shad Alosa sapidissima captured during migrations into the Chesapeake Bay and Nansemond River were electrophoretically surveyed. Malate dehydrogenase and nonspecific esterase displayed polymorphic loci. The esterase polymorphism was used as a biochemical genetic marker to analyze the shad migration through the southern Chesapeake Bay. The genetic composition of the shad migration changed significantly over time indicating that this migration is probably composed of multiple, genetically divergent spawning populations. Results of this study are subject to differing interpretations. Observed temporal heterogeneity may result from separation of northern and James River stocks …

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 …

Changes In The Lower Chesapeake Bay Food-Chain In Presence Of The Sea Nettle Chrysaora-Quinquecirrha (Scyphomedusa), David Feigenbaum, Michael Kelly

OES Faculty Publications

The abundance of 4 levels of the lower Chesapeake Bay food chain (Chlorophyll a, herbivores, ctenophore Mnemiopsis leidyi, and Scyphomedusa Chrysaora quinquecirrha) were moni­tored twice weekly at 4 stations from May 10 through Sep 30, 1982 in the Lafayette and Elizabeth Rivers (Virginia). The herbivore standing stock, largely copepods, declined sharply in late May when M. Jeidyi appeared, but rebounded a month later when C. quinquecirrha medusae reduced the ctenophore population. Despite the additional presence of Aurelia aurita (Scyphomedusa) from Jul onward, herbivore abundance remained at moderate levels until the end of the study period. Phytoplankton abundance fluctuated …

The Distribution Of Phytoplankton In Frontal Regions Of The Lower Chesapeake Bay, Richard V. Lacouture

OES Theses and Dissertations

The spatial and temporal distribution of phytoplankton was measured in relation to frontal areas located in the entrance to the Chesapeake Bay. Phytoplankton biomass, taxonomy, and several physical parameters were measured on fifteen sampling cruises between September,1981 and February, 1983.

Several statistical tests revealed that phytoplankton biomass did not accumulate at the fronts and that generally the distribution of phytoplankton biomass was homogenous across the frontal region. The cell count data indicated that the community structure of the phytoplankton assemblage was usually very similar on both sides of the front. The data which was concerned with temporal variations in the …

The Effect Of Sea Nettle Abundance On The Food Chain Of The Lower Chesapeake Bay, Michael Glenn Kelly

OES Theses and Dissertations

The significance of sea nettle abundance on lower levels of the Chesapeake Bay food chain was examined in a field study and by the analysis of medusa gut contents. In the field study, the abundance of four levels of the food chain (Chlorophyll (a), copepods, the ctenophore Mnemiopsis leidyi, and the Schyphomedusa Chrysaora guinguecirrha) were monitored twice weekly at four stations from May 10 through September 30, 1982. The copepod standing stock declined sharply in late May when M. leidyi appeared, but rebounded a month later when C. guinguecirrha medusae reduced the ctenophore population. Despite the additional presence …

Feeding Morphologies And Distribution Patterns Of Marine Cladocera In The Lower Chesapeake Bay, Sandra Layne Gilchrist

OES Theses and Dissertations

Temporal and spatial distributions of marine cladocera in the lower Chesapeake Bay estuary were observed over a year-long sampling period. The distributions of cladoceran species throughout the Bay were studied in relation to temperature and salinity. A survey of the species over the entire Bay is included to establish distribution patterns of the various species during a short time period.

Theoretical mathematical principles were used to predict feeding abilities of the Bay species. Mouthparts are described qualitatively and quantitatively to infer function. A mandibular index developed by Itoh (1970) was revised and employed in evaluating feeding methods interspecifically and interspecifically. …

Seasonal Composition Of Zooplankton Of Lower Chesapeake Bay And Virginia Coastal Waters, Elizabeth W. Atkinson

Biological Sciences Theses & Dissertations

Abstract unavailable.

The Distribution Of Phytoplankton Along A 140 Mile Transect In The Chesapeake Bay, Harold G. Marshall

Biological Sciences Faculty Publications

The composition of phytoplankton progressively changed in the surface samples taken between Norfolk, Virginia and Cambridge, Maryland. These was an inverse relationship between the numbers of phytoplankters and zooplankters in the transect samples. Vertical stratification of the plankton was studied at two 24-hr, stations at the Great Wicomlco and Patuxent Rivers. The vertical centers of zooplankton and phytoplankton populations fluctuated over the study period and evidence is given to support a grazing phenomenon. Large concentrations of nannoplankters were found in all the plankton samples taken and is attributed to the collection procedure using the Van Dorn sampler.