Marine Biology Commons^™

The Effects Of The Mud Snail Ilyanassa Obsoleta (Say) Upon The Benthic Community Of Broad Bay, Virginia, Wick Timothy Harlan

Biological Sciences Theses & Dissertations

The effects of the presence of the mud snail Ilyanassa obsoleta (Say) upon the benthic community of Broad Bay, Virginia were examined through artificial removal and exclusion of the snail and artificial increase of the snail population. The enclosure treatment exhibited a significantly higher number of macrofaunal individuals than the control. The control had a significantly higher number of meiofaunal individuals than either treatment. There were no significant differences for the chlorophyll a. The increase in macrofauna and corresponding decrease in meiofauna were probably due to cage effects and not snail densities. The presence of the fences can act as …

The Effects Of Dredged Materials On The Copeod, Acartia Tonsa, Renee Suzanne Crouch

Biological Sciences Theses & Dissertations

A study was conducted to determine the potential impact of open ocean disposal of sediments dredged from a highly industrialized seaport. Sediments from three potential dredge sites along the Southern Branch of the Elizabeth River, Hampton Roads, Virginia were evaluated for acute toxicity. The suspended particulate fractions of dredged materials were tested in a series of 96-hour, static bioassays using the calanoid copepod, Acartia tonsa Dana. Significant mortalities were observed for all three sites with the sediments from the most heavily industrialized site producing immediate and severe mortality. Analysis of results indicates that mortality was highly related to the volatile …

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 …

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 …

Adaptations Of Dolphin Vision To The Oceanic Environment, Andre Rivamonte

OES Theses and Dissertations

The objective of this study has been to develop an hypothesis explaining comparable aerial and underwater visual acuity of the bottlenose dolphin, Tursiops truncatus. This objective was accomplished by integrating the findings of other dolphin researchers working in the fields of comparative psychology, histology and ophthalmology. Their combined results enabled the formulation of a schematic dolphin eye. It is proposed that a dolphin lens, similar to the spherical lens of teleost fish with a rigid core of uniformly high refractive index and a margin of radially decreasing refractive index, could function as a bifocal lens and compensate for the eye's …

The Effect Of Crowding On Growth Of The Cichlid Fish, Oreochromis Mossambicus, Bonnie A. Barrows

OES Theses and Dissertations

It has been reported that the Java tilapia, Oreochromis mossambicus, displays hypersensitivity to a substance it produces when biomass levels in a flow-through culture system exceed 20 g/1, resulting in reduced growth and high mortality. Experiments on the growth of this species in small tanks were conducted in order to determine whether O. mossambicus produces a growth-inhibiting compound under crowded conditions. This species was successfully maintained at biomass levels of 38 g/1 and 57 g/1 with a total mortality of only 4.5%.

The Java tilapia can grow rapidly in small aquaria, as indicated by the data taken during Experiment …

Simultaneous Functional Hermaphroditism In The Shrimp Hippolysmata Wurdemanni (Gibbes) (Decopoda: Caridea: Hippolytidae), Marie Hollister Bundy

OES Theses and Dissertations

The caridean shrimp Hippolysmata wurdemanni Gibbes was studied from a histological and a behavioral basis and was found to be a protandric hermaphrodite which later adopts simultaneous functional hermaphroditism. When the animal reaches a certain size, the androgenic gland degenerates, the male secondary sexual characteristics are lost, and vitellogenesis occurs in the anterior portion of the gonad. The animals do not lose the ability to function as males as evidenced by the presence of mature sperm in the gonad and the gonadal lumen of gravid shrimp, and the ability of both members of an isolated pair of shrimp to repeatedly …

The Growth And Feeding Behavior Of Juvenile Spot, Leiostomus Xanthurus Lacepede, In The Nursery Region Of The James River, Virginia, John Thomas Mccambridge Jr.

OES Theses and Dissertations

The in situ growth and feeding behavior of juvenile spot, Leiostomus xanthurus Lacepede, was investigated for populations in the nursery area of the James River, Virginia. Growth of juvenile spot was found to be fairly rapid (11.34 mm/month, standard length) during their first summer in the nursery grounds, but it levelled off in the autumn. The mean size of spot after the first year was calculated to be 195 mm total length. The weight-length relationship was log W = -5.018 + 3.246(log L), where W = wet weight in grams and L = standard length in millimeters.

Juvenile spot appeared …

Polychlorinated Biphenyl Levels In The Ocean Scallop (Placopecten Magellanicus) Gmelin From The Philadelphia Sewage Sludge Disposal Site, Guy Jeffrey Hall

OES Theses and Dissertations

Ocean Scallops (Placopecten magellanicus) were sampled from stations in and around the Philadelphia Disposal Site. Each sample was dissected and aliquots of adductor muscle and reproductive tissue were chemically extracted for Polychlorinated Biphenyls (PCBs). A perchlorinated procedure outlined by Diosady et al., 1972, Aromour, 1973 and Crist et al., 1977 was employed to increase detection levels and simplify quantitation of PCBs. PCB levels were reported in dry weight and lipid weight of both adductor muscle and reproductive tissue. Findings indicated residual levels or PCB/lipid weight increased as lipid levels decreased in both tissue types. Levels detected in all adductor muscle …

The Cousteau Log Centering On Marine Animals For Elementary School Children, Annie Suffron

All Graduate Projects

"Centering on Marine Animals for Elementary School Children" was a multi-curricular learning center design in four parts. It consisted of an introduction on Bubbles the Whale, including a picture, a puppet, a song, a Sea Script, and task cards. Following the introduction were three units on Sea Monsters of the World, the Migration of the Grey Whale, and the Ecology of the Southern Sea Otter. Each unit contained a picture of the sea animal, a puppet, a song, a Sea Script, a Quiz, map(s), and task cards.

A Statistical Model To Predict The Incidence Of Pathogenic Protozoa (Amoebida: Acanthamoebidae) In Oceanic Sediments Using Surrogate Variables, Carl Robert Berman Jr

Dissertations, Theses, and Masters Projects

Surrogate contaminant variables (heavy metals, organics, physical oceanograpic data) can be used to predict the incidence of positive cultures of Acanthamoeba sp. in oceanic sediments. Amoebae data are drawn from five years of study involving stations in Narragansett Bay, Rhode Island, the New York Bight, and the Philadelphia-Camden dumpsite, and associated pollution parameters are drawn from literature sources, computerized marine pollution data bases, and other archives. The Statistics Analysis System (SAS) MAXR('2) improvement technique (stepwise regression) and general linear model procedures are used to generate correlations for surrogate variables and produce final predictive models and tables. Model procedures for the …

Energy Utilization In Bay Anchovy And Black Sea Bass Eggs And Larvae Contrasting Ecological Roles, John Wotring Tucker Jr

Dissertations, Theses, and Masters Projects

The objective of this study was a comparison of developmental changes and energy utilization in eggs, unfed larvae, and fed larvae of two marine fish species that both have pelagic early stages, but differ in phylogeny and early life ecology. The bay anchovy (Anchoa mitchilli), a clupeiform, spawns in estuaries and shallow coastal waters. The black sea bass (Centropristis striata striata), a perciform, spawns offshore at 15-50 m depths. Densities of zooplankton eaten by first-feeding fish larvae are normally higher in coastal waters than offshore. An important determinant of survival of larval fishes is their ability to fulfill nutritional requirements …

Benthic Polychaeta Of The Middle Atlantic Bight: Feeding And Distribution, Gary Russell Gaston

Dissertations, Theses, and Masters Projects

Patterns in the distribution of feeding-biology categories of polychaetous annelids were used to characterize benthic habitats of the Middle Atlantic Bight. Feeding biology classifications were based on recent publications regarding polychaete feeding and on gut-contents analyses of polychaetes collected in the study area. Proportion of carnivorous polychaetes was greatest in coarser sediments, and decreased significantly with depth across the continental shelf. Surface deposit feeders numerically dominated most habitats. Abundance of surface deposit feeders decreased across the continental shelf and sharply increased at the shelf break, paralleling the pattern of water-column production. Proportion of subsurface deposit feeders was greatest in fine-sediment …

An Environmental Model Predicting The Relative Recruitment Success Of Blue Crab, Callinectes Sapidus (Rathbun), In Chesapeake Bay, Virginia, Andrew Jackson Applegate

Dissertations, Theses, and Masters Projects

No abstract provided.

Distribution Of Macrobenthic Invertebrates On The North Carolina Continental Shelf With Consideration Of Sediment, Hydrography And Biogeography, Donald Paul Weston

Dissertations, Theses, and Masters Projects

The macrobenthic invertebrates of the North Carolina continental shelf in the vicinity of Cape Hatteras were sampled during four seasonal cruises, June 1977 to January 1978. Macrobenthos-sediment relationships were investigated in the area surrounding Diamond Shoals. Four benthic assemblages were recognized, each representative of specific sediment regimes. The results of multivariate analyses were interpreted as indicating that the percentages of very fine sand and silt and clay were of greatest biological significance. It is suggested that the importance of finer particles is due to their influence on sediment permeability and organic content. The degree of particle sorting was also important …

Climate Scale Environmental Factors Affecting Year-Class Fluctuations Of Atlantic Croaker (Micropogonias Undulatus) In The Chesapeake Bay (Maryland, Virginia), Brenda L. Norcross

Dissertations, Theses, and Masters Projects

A conceptual life history of the Atlantic croaker (Micropogonias undulatus) identifies the effects of the environment on juvenile recruitment. In a multi-disciplinary approach to modelling, the major effects are investigated, quantified and presented in a flow chart. The model is divided into three sub models, each representing a major component which affects juvenile recruitment. North/south spawning location in the Mid-Atlantic Bight is affected by the bottom water temperature as influenced by the cessation of the summer winds in relation to timing of croaker migration. The pelagic phase is the most critical time in the life history of a larval croaker …

Life History And Secondary Production Of The Crustacean Gammarus Mucronatus Say (Amphipoda: Gammaridae) In Warm Temperate Estuarine Habitats, York River, Virginia, Thomas J. Fredette

Dissertations, Theses, and Masters Projects

In order to assess the secondary production potential of the amphipod Gammarus mucronatus its life history was examined with laboratory experimentation and field sampling in two warm temperate estuarine habitats in the York River, Virginia. A seagrass (Zostera marina) bed and a macroalgae (Ulva spp., Enteromorpha spp.) fouling community on old pier pilings. Variations in amphipod abundance between the habitats were not similar. G. mucronatus was present in the seagrass habitat during most of the year attaining maximum densities of 1200(.)m('-2) in the spring. Presence of G. mucronatus in the macroalgae habitat was almost totally restricted to late spring and …