Marine Biology Commons^™

A Phylogeny Of Genera Of The Fish Family Nemipteridae (Percoidei) Based On The Cytochrome B Gene, Denise R. Sliter

Biological Sciences Theses & Dissertations

The species level taxonomy of the Nemipteridae is well understood but existing morphological data is insufficient to hypothesize a phylogeny of the five genera of this family of percoid fishes. Furthermore, there are three distinct and widely disparate habitat requirements within nemipterids and little is known how these evolved. Species in the genera Pentapodus, Scaevius and Scolopsis are typically found around shallow reefs. Nemipterus species are also found in shallow-water, but they inhabit strictly soft sediment bottoms. Parascolopsis is the only deep-water genus and its species are also found over soft sediments. Complete cytochrome b gene sequences (1140 base …

Relating Water And Otolith Chemistry In Chesapeake Bay, And Their Potential To Identify Essential Seagrass Habitats For Juveniles Of An Estuarine-Dependent Fish, Spotted Seatrout (Cynoscion Nebulosus), Emmanis Dorval

Biological Sciences Theses & Dissertations

A quantitative understanding of habitat use of estuarine-dependent fishes is critical to the conservation of their most essential habitats. Because recruitment and fitness may be influenced by the quality of juvenile habitats, developing methods to quantify habitat-specific survivorship is pivotal to such understanding. An initial step to quantify survivorship is to validate the habitat-specific natural tags contained in otoliths. To this aim I investigated the variability in the chemistry of surface waters and otoliths of juvenile spotted seatrout, Cynoscion nebulosus, in five seagrass habitats of Chesapeake Bay, namely: Potomac, Rappahannock, York, Island, and Eastern Shore. I measured Mg, Ca, …

Characterization Of Association Patterns Of Coastal Migratory Bottlenose Dolphins, Tursiops Truncatus, In The Nearshore Waters Of Virginia Beach, Virginia, Holly Fearnbach

Biological Sciences Theses & Dissertations

Bottlenose dolphins, Tursiops truncatus, commonly occur in fission-fusion social systems. For this study, I analyzed photo-identification data from 1994 to 1999 to describe association patterns of bottlenose dolphins in the nearshore waters of Virginia Beach, Virginia. Bottlenose dolphins are present seasonally (late April until early November) in these waters and individuals are considered to be members of the North Atlantic coastal migratory stock. I selected 78 individuals for detailed analyses from the 972 dolphins identified in the study area. Those chosen as “select” dolphins had been sighted at least five times in three of the six study years; all …

Feeding Responses Of Juvenile And Adult Streblospio Benedicti Webster (Spionidae) To Organic Chemicals Bound To Glass Microbeads, Heidi Kathryn Mahon

Biological Sciences Theses & Dissertations

Spionid polychaetes feed at the sediment-water interface using a pair of ciliated palps. Polychaetes select food particles based upon characteristics including size, texture, specific gravity and organic coatings. Juvenile and adult spionids have different stable isotopic carbon signals, indicating the potential to differentiate organic cues ontogenetically. In the present study, the feeding responses of juvenile and adult Streblospio benedicti Webster to seven organic coatings bound (five amino acids and two carbohydrates) to glass microbeads were tested. Juveniles and adults were highly selective for all seven types of organically coated beads. Juveniles were highly selective for threonine; whereas adults were highly …

Male Reproductive Dynamics In The Caribbean Spiny Lobster Panulirus Argus, Jamie S. Heisig

Biological Sciences Theses & Dissertations

The population size structure of the Caribbean Spiny Lobster, Panulirus argus, in the Florida Keys, Florida (USA) has undergone a dramatic shift as a result of fishing pressure on the large individuals of the population. Male lobsters are affected most by fishing because of sexual dimorphism in size and other studies have shown that male size has direct impacts on reproductive output (i.e., number of fertilized eggs/clutch) that are independent of female size. To assess more precisely the impact of male size on fertilization success, I conducted laboratory experiments and field observations to examine various male reproductive attributes over …

The Ecological Ramifications Of Disease And Density In The Caribbean Spiny Lobster, Panulirus Argus, Donald C. Behringer Jr.

Biological Sciences Theses & Dissertations

In 1999, I discovered the first virus known to be pathogenic to any species of lobster. HLV-PA is a pathogenic herpes-like virus that infects juvenile Caribbean spiny lobster, Panulirus argus, in the waters off south Florida (USA), and it alters the behavior and ecology of this species in fundamental ways. Gross signs of HLV-PA infection are lethargy, morbidity, cessation of molting, and discolored, “milky” hemolymph that does not clot. HLV-PA infects the hemocytes of host lobsters, specifically the hyalinocytes and semi-granulocytes, but not the granulocytes. When hemolymph from infected donors was injected into healthy juvenile lobsters, 90% of the …

Recruitment Variability Of Atlantic Croaker, Micropogonia Undulatus, With Observations On Environmental Factors, Sumalee Hoskin

Biological Sciences Theses & Dissertations

I examined entrance patterns of Atlantic croaker, Micropogonias undulatus by comparing the abundance, length, age and growth rates, of larvae as they entered Oregon and Ocracoke Inlets, NC. These biological factors were then compared against environmental factors to assess the influence the physical environment has on recruitment variability. Entrance abundance into Oregon Inlet was an order of magnitude higher than abundance into Ocracoke Inlet. However, the difference was influenced by three peak events in Oregon Inlet and non-parametric tests found no difference in median abundance between the two inlets. Mean standard length was smaller at Oregon Inlet than Ocracoke Inlet …

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 …

Seasonal Phytoplankton Assemblages Of Five Ephemeral Ponds In York County, Virginia, Michelle R. Kokolis

Biological Sciences Theses & Dissertations

Five ephemeral ponds were identified in and around the Grafton Ponds Natural Area Preserve, approximately 56 km north of the City of Norfolk, Virginia. These ponds, which are filled seasonally by precipitation and groundwater discharge, range from 0.1 ha to 2 ha in size and from 4 cm to 3 meters in depth. Ponds for the study were chosen based on variations in their size, depth, basin cover material, canopy openness, and historical inundation period. The purpose of this study is to relate differences in the phytoplankton assemblages to the physical and chemical characteristics of the ponds. All five ponds …

The Implications Of The Target-Area Hypothesis On The Population Dynamics Of The Spotted Spiny Lobster, Panulirus Guttatus, Denice N. Robertson

Biological Sciences Theses & Dissertations

The target-area hypothesis, based on the theory of island biogeography, predicts that larger islands are more effective at intercepting passive immigrants. Most marine invertebrates have meroplanktonic larvae and open population dynamics, so immigration to populations in isolated benthic habitats is primarily by pelagic larval recruits. Thus, recruitment to isolated habitat “islands” may be more continuous and predictable on large islands than on small ones. Consequently, populations on large islands should not only be larger than those on small islands, but should also have more evenly distributed size structures. These differences in size structure among populations in isolated habitats of differing …

Biological And Physical Observations On Larval Spot (Leiostomus Xanthurus) Recruiting To Oregon And Ocracoke Inlets North Carolina, Thomas R. Wasaff

Biological Sciences Theses & Dissertations

Patterns of abundance, length, age, and growth of larval spot (Leiostomus xanthurus) were compared to assess the variability between spot larvae ingressing to two North Carolina inlets. The source of variability for the recruitment of larval fishes to estuarine nurseries has been linked to environmental stochasticity. Wind data and seasurface temperature satellite images were analyzed as two influential environmental variables that may help explain recruitment variability. As part of the South Atlantic Bight Recruitment Experiment (SABRE), spot larvae were collected between October 1994 and April 1995 as they recruited to Pamlico Sound through Oregon Inlet, located north of Cape Hatteras, …

Comparative Systematics Of Subterranean Amphipod Crustaceans In The Families Crangonyctidae And Bogidiellidae, Stefan Koenemann

Biological Sciences Theses & Dissertations

The research project presented in this doctoral dissertation deals with the systematics of two different taxonomic groups of subterranean amphipods (Crustacea). Therefore, rather than being a single project, this study is divided into several sub-projects. Altogether, the chapters for the sub-projects are composed of five publications. An introductory chapter and a summarizing discussion are added to provide a structural unit for the collection of papers and to compare the results of the individual projects.

The thesis investigates the systematics of the amphipod families Bogidiellidae Hertzog, 1936, and Crangonyctidae Bousfield, 1973. Based on descriptive taxonomy according to modern standards, revisions are …

The Impact Of Resident And Transient Predators On The Popultation Dynamics Of Juvenile Caribbean Spiny Lobster (Panulirus Argus) In Florida Bay, Florida, Jason Edward Schratwieser

Biological Sciences Theses & Dissertations

There has been a considerable amount of research devoted to exploring the relationship between predators and prey, but many of these studies fail to address how predation can vary over spatial and temporal scales. The tendency of ecologists to model predation as a static entity often masks its capacity for creating distinctive effects in prey populations and communities. Most predation studies also focus on the effect of a single species of predator on a prey population, an unrealistic situation in nature. In the Florida Keys, juvenile spiny lobsters are subjected to two general classes of predators: i) "resident" predators such …

A Study Of The Seasonal Composition And Abundance Of Phytoplankton And Autotrophic Picoplankton In A Brackish Water Lake In Portsmouth Virginia, Jennifer Leigh Wolny

Biological Sciences Theses & Dissertations

The phytoplankton and autotrophic picoplankton populations of Hoffler Lake, a brackish-water lake in Portsmouth, Virginia, were monitored from May 1997 through May 1998, Analyses of the phytoplankton community using the Utennohl method showed a dominance of Chlorophytes (61-88% of the total abundance) throughout the year, including a winter bloom of Chlamydomonas snowii (maximum concentration of 2.5 x 101 cells/L). Subdominants were Cyanobacteria (10-33% of the total abundance) whose composition included several species of Anabaena, Lyngbya, and a fall bloom of Microcoleus sp. Diatoms, dinoflagellates, and cryptophytes played a secondary role in the phytoplankton community of Hoffler Lake. …

Effect Of Sampling Errors On Estimates Of Recruitment And Fishing Mortality From Separable Virtual Population Analysis, Emmanis Dorval

Biological Sciences Theses & Dissertations

Separable virtual population analysis (SVPA) models provide estimates of historical recruitment and fishing mortality from analyzing catch data based on the separability of fishing mortality into age specific-gear selection and yearly mortality. These models assume that the catch is randomly sampled and that sampling error is a random variable with constant variance and mean equal to zero. These models do not account for sampling measurement errors that occur when the catch partitioned by age is not measured on every sampling unit without error, and spatio-temporal errors that occur when the observed catch is not representative of the harvested population throughout …

Stomach Content Analysis Of Stranded Bottlenose Dolphins, Tursiops Truncatus, In Virginia, 1987-1996, John Mcgurk

Biological Sciences Theses & Dissertations

I examined the stomach contents from 94 bottlenose dolphins, Tursiops truncatus, that were stranded along the Virginia coastline from 1987 through 1996. Samples from 1987 through 1991 were obtained from the National Museum of Natural History (NMNH) and samples from 1992 through 1996 were collected by the Virginia Marine Science Museum (VMSM) Stranding Team. Prey species were identified using fish otoliths and cephalopod beaks.

The dolphins examined fed on 23 species of fish and one genus of cephalopods. The primary prey species was Atlantic croaker (Micropogonias undulatus); secondary species were weakfish (Cynoscion regalia), spot (Leiostomus xanthurus), silver perch (Bairdiella chrysoura), …

Ecology Of The Early Life History Of The Caribbean Spiny Lobster, Panulirus Argus: Recruitment, Predation, And Habitat Requirements, Charles A. Acosta

Biological Sciences Theses & Dissertations

Recruitment variability of the early life history stages of marine benthic organisms can have profound consequences on population dynamics. I studied factors affecting recruitment success of postlarvae and early juveniles of the Caribbean spiny lobster. I examined patterns in postlarval supply, investigated wind forcing as a potential transport mechanism for recruiting postlarvae, and quantified predation on postlarvae in south Florida, USA. In an eight-year time series, spiny lobster postlarval supply occurred year-round between the new and first quarter lunar phases. The major annual peak occurred around March corresponding to spawning activity ten months earlier, and a smaller non-seasonal peak occurred …

Microzooplankton Dynamics In Lower Chesapeake Bay And Its Major Tributaries, Gyung Soo Park

Biological Sciences Theses & Dissertations

This study identified the temporal and spatial variability of microzooplankton density and biomass at 14 stations located within Chesapeake Bay and four rivers. Microzooplankton are defined as those heterotrophic organisms which range from 20 to 200 $\mu$m in size, and in this study were mainly composed of copepod nauplii, rotifers, and ciliates. Ciliates were the most abundant microzooplankton, comprising more than 90% of the total density, with copepod nauplii representing approximately 50% of the total microzooplankton biomass (carbon content). Rotifers contributed less than 5% for both density and biomass of the total microzooplankton.

Maximum ciliate abundance occurred from spring to …

Nutritional Condition Of Striped Bass (Morone Saxatilis) Larvae As Determined By Constituent Lipid Analysis, William Frank Patterson Iii

Biological Sciences Theses & Dissertations

Larval striped bass were reared in the laboratory from 6 days post-hatch (dph) to 21 dph under four different feeding regimes to assess the effect of food concentration on triacylglycerol to sterol ratios (TG:ST) of larvae. Larvae were fed Peru strain Artemia salina nauplii in concentrations of 0, 10, 100, and 10001·1^-1, with three replicate tanks within each feeding treatment. Larvae were sampled on 14 and 21 dph and frozen in liquid nitrogen. Lipids were extracted from larvae in a 90:10:1 solution of dichlormethane:hexane:formic acid and analyzed with thin-layer chromatography/flameionization detection. Analysis of larval constituent lipids, and calculation …

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 …

Seasonal Phytoplankton Dynamics In The Pagan River, David Wade Seaborn

Biological Sciences Theses & Dissertations

The composition and seasonal abundance patterns for phytoplankton in the Pagan River, Virginia, were determined. This river is characterized as a nutrient enriched system with annual mean levels of total nitrogen and phosphorus at 1.8 and 0.8 mg/I respectively. Three phytoplankton maxima occurred during the year with the highest in fall, followed by summer and spring peaks. A diatom flora was dominant throughout the year at concentrations of 107 to 108 cells/I. Other algal populations exhibited distinct periods of abundance, which seasonally varied in magnitude and time of development. Turbidity levels were high throughout the year, with a mean secchi …

Eutrophication And Macrobenthic Communities Of The Lower Chesapeake Bay: Effects Of Organic Enrichment In Pocomoke Sound, Saxis Virginia, Janice D. Mcdonnell

Biological Sciences Theses & Dissertations

The effects of organic enrichment on benthic community structure were evaluated in a field study conducted in Pocomoke Sound in the vicinity of a seafood processing plant. The empirically derived Species Abundance and Biomass (SAB) curves of Pearson and Rosenberg (1978) were used to model patterns of organic enrichment at the study site, called Pig Point, as well as two reference sites located within Pocomoke Sound. The Split Moving Windows (SMW) method was used to detect the ecotone point as defined in the Pearson and Rosenberg (1978) model and the Two Term Local Quadrat Variance (TTLQV) method was used to …

Reproductive Biology Of Chesapeake Bay Black Drum, Pogonias Cromis, With An Assessment Of Fixatives And Stains For Histological Examination Of Teleost Ovaries, Brian K. Wells

Biological Sciences Theses & Dissertations

Based on three years of data collection on the periodicity of the spawning run, the gonadosomatic index (GSI), and gonad histology, the spawning season for Chesapeake Bay black drum was found to be significantly shorter and later compared to populations from Florida and the Gulf of Mexico. The GSI is maximal in early April when black drum first enter the Chesapeake Bay region in contrast to data from Florida where GSI peaks during February and March. I confirm that black drum from the Chesapeake Bay are batch spawners. These results match those found for populations of black drum in the …

The Influence Of Temperature Salinity And Postlarval Transport On The Distribution Of Juvenile Spiny Lobsters, Panulirus Argus, In Florida Bay, Jennifer Marie Field

Biological Sciences Theses & Dissertations

Florida Bay is a major nursery for the Caribbean spiny lobster, Panulirus argus. The Bay contains a series of hardbottom or seagrass-covered basins separated by mudbanks, which serve as barriers to water circulation and presumably to transport of postlarvae. Temperatures can fluctuate dramatically in the basins and salinities range from 35 ppt to > 50 ppt. In this study I: i) investigated the physiological tolerance of spiny lobster postlarvae to combinations of temperature and salinity representative of conditions in Florida Bay, and ii) examined how postlarval availability and habitat structure influence spiny lobster recruitment into basins. I measured juvenile lobster …

Phytoplankton Assemblages Associated With A Bloom Of Ptychodiscus Brevis Off The North Carolina Coast, Traycie Lea West

Biological Sciences Theses & Dissertations

A bloom of the dinoflagellate Ptychodiscus brevis occurred off the North Carolina coast in late 1987, and samples were forwarded by NOAA to the Old Dominion University Phytoplankton Laboratory for total phytoplankton analysis. Six sampling stations were chosen to represent different bloom scenarios and these six were clustered into three site groups based on the concentrations of statistically significant taxa. Abundances of phytoplankton taxonomic groups over time were examined in relation to P. brevis concentrations to identify any general tendencies. These results indicated the total phytoplankton concentration, and most taxonomic groups, increased at all three site groups regardless of the …

Age And Growth Of Larval And Juvenile Atlantic Croaker, Micropogonias Undulatus, From The Middle Atlantic Bight And Estuarine Waters Of Virginia, Stephen W. Nixon

Biological Sciences Theses & Dissertations

Sagittal otoliths were used to determine the age and growth of 605 larval and juvenile Atlantic croaker, Micropogonias undulatus, collected in the Middle Atlantic Bight (MAB) and estuarine waters of Virginia. A Laird-Gompertz model (r2 = 0.95) was used to describe the growth of croaker up to 65 mm standard length (SL) and 142 days (t): S1_(t) = 2.657 Exp {4.656 [1-Exp (-0.008lt)]}; SL_(t) = standard length at day t. Generally, croaker collected inshore were larger and older than those collected offshore, indicating estuarine immigration from offshore spawning grounds. Back-calculated hatch-dates indicated spawning over an 8- month period …

Evaluation Of Long Term Changes In The Macrobenthic Community Of The Southern Branch Of The Elizabeth River, Virginia, William S. Hunley

Biological Sciences Theses & Dissertations

Long-term changes in the macrobenthos of the Southern Branch of the Elizabeth River, Virginia were investigated by comparing the present study of community structure with that described ten years earlier by Hawthorne (1980). The results indicated that dominant organisms remained relatively constant in composition but exhibited considerable fluctuation in density. Differences in diversity and spatial distribution of fauna were also observed relative to the previous decade.

Multivariate statistical analyses indicated the macrobenthos exhibited significant spatial and seasonal patterns. Sediments characterized as silts and clays predominated down river while sandier sediment types were most common farther upriver. The spatial distributions of …

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 …

A Laboratory Study Of Predation On The Trinidadian Guppy, Poecilia Reticulata, By Two Natural Piscine Predators: Effects Of Predator Size, Prey Size, And Habitat Complexity, Hayden Thomas Mattingly

Biological Sciences Theses & Dissertations

Test populations of different-sized guppies, Poecilia reticulata, were exposed to individuals of two natural predatory species, the pike cichlid Crenicichla a/ta and the killifish Rivulus harti, under conditions of varying prey (guppy) density and habitat complexity in the laboratory. Rivulus fed most frequently on newborn and juvenile guppies < 14 mm. Crenicichla consumed more and larger guppies than did Rivulus. The mean guppy size eaten by Crenicichla was dependent on the length of the individual predator, but as a group, the 15 Crenicichla tested were non-selective with respect to guppy size and gender. The prey gender preference of Rivulus could not he determined …

Community Structure Of The Macrobenthos In Back Bay, Virginia, Michael F. Lane

Biological Sciences Theses & Dissertations

A study of the subtidal macrobenthos in Back Bay, Virginia was conducted to examine community structure in relation to sedimentary and water quality characteristics. Samples were collected in August and November of 1987 and February and May of 1988 at ten stations.

Three site groups and three temporal groups were identified by cluster analyses of species abundance. Species composition between site groups was relatively homogeneous and eight species accounted for most of the variation between site groups. A comparison of plots of the biological and physical data in discriminant space suggested that variations in the biological data between site groups …