Aquaculture and Fisheries Commons^™

Predicting Fish Species Diversity In Lotic Freshwaters Of Greece, Eugene G. Maurakis, David V. Grimes

Virginia Journal of Science

Objectives were to test the hypothesis that stream order and stream width alone account for species diversity in drainages of Greece, and to create a mathematical model that predicts fish diversity in small and medium sized freshwater streams in the southern Balkan Peninsula in accord with the stream classification system proposed by the European Environmental Agency (EEA). Thirty-seven species of fishes in 12 families (Petromyzontidae, Anguillidae, Cyprinidae, Moronidae, Centrarchidae, and Blenniidae) were collected in five stream orders (1-5) from 19 river drainages in Greece in 1993 and from 2000-2002. Numbers of species were significantly correlated with stream order (+), width …

Identification Key To Fishes In Fresh Waters Of Greece, Eugene G. Maurakis, Panos S. Economidis

Virginia Journal of Science

The European Environmental Agency formulated a biodiversity initiative in 1996 specifying a freshwater stream-monitoring program to inventory, identify and describe aquatic and terrestrial species in European Union countries. With one of the richest freshwater ichthyofaunas in Europe (126 fish taxa: 97 species and 29 subspecies of primary or secondary freshwater fishes), Greece has two extinct fish species, five listed as critically endangered, and 29 considered endangered and/or vulnerable. There are, however, no published identification guides that are available for identifying fish specimens from fresh waters in Greece. We present an English translation of the only available identification key (in Greek) …

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 …

Experimental Mycobacteriosis In Striped Bass Morone Saxatilis, D. T. Gauthier, M. W. Rhodes, W. K. Vogelbein, H. Kator, C. A. Ottinger

Biological Sciences Faculty Publications

Striped bass Morone saxatilis were infected intraperitoneally with approximately 10⁵ Mycobacterium marinum, M. shottsii sp. nov., or M. gordonae. Infected fish were maintained in a flow-through freshwater system at 18 to 21°C, and were examined histologically and bacteriologically at 2, 4, 6, 8, 17, 26, 36 and 45 wk post-infection (p.i.). M. marinum caused acute peritonitis, followed by extensive granuloma development in the mesenteries, spleen and anterior kidney. Granulomas in these tissues underwent a temporal progression of distinct morphological stages, culminating in well-circumscribed lesions surrounded by normal or healing tissue. Mycobacteria were cultured in high numbers from …

Hydrodynamic Stability Of Swimming In Ostraciid Fishes: Role Of The Carapace In The Smooth Trunkfish Lactophrys Triqueter (Teleostei : Ostraciidae), Ian K. Bartol, Morteza Gharib, Daniel Weihs, Paul W. Webb, Jay R. Hove, Malcolm S. Gordon

Biological Sciences Faculty Publications

The hydrodynamic bases for the stability of locomotory motions in fishes are poorly understood, even for those fishes, such as the rigid-bodied smooth trunkfish Lactophrys triqueter, that exhibit unusually small amplitude recoil movements during rectilinear swimming. We have studied the role played by the bony carapace of the smooth trunkfish in generating trimming forces that self-correct for instabilities. The flow patterns, forces and moments on and around anatomically exact, smooth trunkfish models positioned at both pitching and yawing angles of attack were investigated using three methods: digital particle image velocimetry (DPIV), pressure distribution measurements, and force balance measurements. Models …

Demographic Assessment Of The Blue Crab (Callinectes Sapidus) In Chesapeake Bay Using Extractable Lipofuscins As Age Markers, Se-Jong Ju, David H. Secor, H. Rodger Harvey

OES Faculty Publications

The blue crab (Callinectes sapidus) plays an important economic and ecological role in estuaries and coastal habitats from the Gulf of Mexico to the east coast of North America, but demographic assessments are limited by length-based methods. We applied an alternative aging method using biochemical measures of metabolic byproducts (lipofuscins) sequestered in the neural tissue of eyestalks to examine population age structure. From Chesapeake Bay, subsamples of animals collected from the 1998-99 (n-769) and 1999-2000 (n=367) winter dredge surveys were collected and lipofuscin was measured. Modal analysis of the lipofuscin index provided separation into three modes, whereas carapace-width …

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 …

Autotrophic Picoplankton: Their Presence And Significance In Marine And Freshwater Ecosystems, Harold G. Marshall

Virginia Journal of Science

Invited lecture: Autotrophic Picoplankton Workshop, 52nd Congress of the Polish Botanical Society, Adam Mickiewicz University, Poznan, Poland, September 2001 .

Reproductive Differences Among Delmarva Grass Shrimp (Palaemonetes Pugio And P. Vulgaris) Populations, Holly H. Ganz, Robert E. Knowlton

Virginia Journal of Science

Populations of female grass shrimps (Palaemonetes pugio and P. vulgaris) were sampled from five coastal embayments in Delaware, Maryland, and Virginia (Delmarva) and compared with respect to reproductive and life history attributes. We observed interspecific differences in timing of reproduction, carapace length, ratio of carapace length to total body length, body weight, clutch weight, clutch size, and egg volume. Onset of reproduction in P. vulgaris lagged behind P. pugio. Although there was no difference in the relationship between clutch size and carapace length for the two species, carapace length/total body length in P. pugio was greater than …

Vertical Distributions Of Zooplankton At The Mouth Of Chesapeake Bay And Calibration Of Backscatter From An Acoustic Doppler Current Profiler, Arthur Keith Jenkins

Biological Sciences Theses & Dissertations

This study investigated the physical factors influencing the vertical distribution of zooplankton at the mouth of the Chesapeake Bay and attempted to derive biological data from acoustic Doppler current profiler (ADCP) backscatter. A single site was occupied in the North Channel at the mouth of Chesapeake Bay (37° 04' N, 75° 58' W) from 17.0–19.7 November 1999. Temperature, salinity, fluorescence, light transmission, current velocity and backscatter were measured throughout the sampling period. Plankton samples were collected every hour from 3.5, 7.5, and 11.5 m.

We found little association between ADCP backscatter and plankton concentrations, but stronger correlations between backscatter and …

Response Of Anchovy (Engaulis Ringens) Off Northern Chile To The 1997-1999 El Niño-La Niña Sequence, José L. Blanco, Patricio Barria, Jorge Castillo, Larry P. Atkinson

CCPO Publications

No abstract provided.

Length-At-Age In Juvenile Patagonian Toothfish (Dissostichus Eleginoides), J. Ashford, C. Jones, S. Bobko, I. Everson

OES Faculty Publications

We used the otoliths from a sample of Dissostichus eleginoides pre-recruits, whose length density was distinctly polymodal, to see whether ages estimated by reading otoliths were congruent with the length modes observed. Length densities by age were compared graphically with the overall length density observed. Additionally, ages were predicted for each fish based on length, and compared with ages estimated from reading otoliths in a goodness-of-fit test. The majority of the otoliths (83.6%) were estimated to be from fish 1+ or 2+ years old, with mean total lengths of 32.5 cm and 41.3 cm respectively. No difference was found between …

Development Of An Electrotransformation Technique For Streptococcus Iniae And Preliminary Characterization Of The Hemolysin Associated With This Bacterium, Kimberly Ann Hahn

Biological Sciences Theses & Dissertations

Streptococcus iniae is a gram-positive organism responsible for causing disease in both freshwater as well as saltwater fish. Every year fisheries lose fish by the tons due to diseases caused by this organism. In 1991, the first reported human case of disease associated with this organism was described. Since this initial case, there have been numerous other reported cases of S. iniae infections. This organism is a catalase negative, facultatively anaerobic organism that produces a capsule and when plated onto blood agar demonstrates β-hemolytic activity.

In this study, the relationship between the hemolysin produced by S. iniae and the lactate …

In Support Of A Rationally Managed Fishery: Age And Growth In Patagonian Toothfish (Dissostichus Eleginoides), Julian R. Ashford

Biological Sciences Theses & Dissertations

Patagonian toothfish (Dissostichus eleginoides) occur on the continental shelves and shelf breaks of southern South America and the Southern Ocean. Stock structure, critical to good fisheries management, can be inferred from growth differences between areas, but available growth data are compromised by inconsistencies in age estimation methods, sampling and sample sizes, and techniques used to derive estimates. I asked the scientific question: how is growth in Patagonian toothfish structured spatially within the Southern Ocean? I developed a multi-stage randomized design to sample fish caught by commercial longline, and an age estimation methodology. Because toothfish are difficult to age, …

The 6th International Conference And Workshop On Lobster Biology And Management: An Introduction, Mark J. Butler Iv

Biological Sciences Faculty Publications

Every three years or so, the International Conference and Workshop on Lobster Biology and Management (ICWL) brings together lobster scientists, fishery managers, and industry representatives from around the world for a week of scientific presentations, workshops, and discussions on lobster biology and management. The first ICWL was held in Perth, Australia, in January 1977. Its purpose was to bring together a small group of lobster researchers from the USA and Australia to discuss common issues and themes. That initial workshop spawned a continuing series of meetings that have become the international lobster conference for scientists—the equivalent of an international congress …

Yield-Per-Recruit Analysis For Black Drum, Pogonias Cromis, Along The East Coast Of The United States And Management Strategies For Chesapeake Bay, Cynthia M. Jones, Brian K. Wells

OES Faculty Publications

Black drum, Pogonias cromis along the U.S. East Coast is subject to commercial and recreational harvest. However, prior to this study no modeling had been undertaken to examine the potential for overfishing in the Chesapeake Bay region. We present evidence from yield-per-recruit models that growth overfishing of black drum is unlikely under current fishing practices in this region. Particular attention was given to fishing practices in the Chesapeake Bay region where old, large fish predominate in the commercial and recreational catches (mean age=26 years: mean total length=108.4 cm; mean weight 22.1 kg). Yield-per-recruit model results showed that growth overfishing was …

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 …

Effects Of Blood Extraction On The Mortality Of The Horseshoe Crab, Limulus Polyphemus, Elizabeth A. Walls, Jim Berkson

Virginia Journal of Science

Horseshoe crabs (Limulus polyphemus) are bled by biomedical companies for the extraction of Limulus Amoebocyte Lysate (LAL), a clotting agent used in the detection of endotoxins. In 1998, the Atlantic States Marine Fisheries Commission mandated that all biomedical companies collecting horseshoe crabs for the production of LAL study the horseshoe crab mortality rates resulting from the company's blood extraction process. BioWhittaker, a Cambrex Company is one of the largest producers of LAL in the world. During the summer of 1999, bled and unbled horseshoe crabs were transported from BioWhittaker's bleeding facility in Chincoteague, Virginia to the Virginia Seafood …

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, …

Comparison Of Larval Myomere Counts Among Species Of Nocomis In Virginia (Actinopterygii: Cyprinidae), Terre D. Green, Eugene G. Maurakis

Virginia Journal of Science

Larval myomere counts of Nocomis platyrhynchus were made using a dissecting light microscope equipped with polarizing filters, and then compared to those of the three other species of Nocomis (Nocomis leptocephalus, Nocomis micropogon, and Nocomis raneyi) found in Virginia. Average preanal myomere counts for N. platyrhynchus (26.9) were significantly different from those of the other three species (N. raneyi =28.7; N. micropogon =26.0; and N. leptocephalus =25.9). This is especially important as larvae of N. leptocephalus, the only other species of Nocomis syntopic with N. platyrhynchus in the upper New River drainage, can now …

Feeding Habits Of Young-Of-Year Striped Bass, Morone Saxatilis, And White Perch, Morone Americana, In Lower James River, Va, Paul J. Rudershausen, Joseph G. Loesch

Virginia Journal of Science

A total of 188 young-of-year (YOY) striped bass, Morone saxatilis, and 199 YOY white perch, Morone americana, were collected by pushnet, seine and trawl during 24-hour periods from June through August, 1992 in lower James River, Virginia. The purpose was to identify prey and temporal and spatial feeding habits. Copepods were the most numerous prey of both species. Fishes and mysids comprised the largest volumetric percentage of diets of striped bass and white perch, respectively. Using an index of relative importance, leptodorids and copepods were the most important prey of striped bass and white perch, respectively. Both species …

Evaluation Of Fish Scale Chemistry For Determining Habitat Associations, Brian Kenneth Wells

Biological Sciences Theses & Dissertations

This is the first work examining the utility of scale chemistry for determining natal origins and habitat associations. I quantified a relationship of scale chemistry to water chemistry, quantified geographic variation in scale chemistry, and evaluated stability of scale chemistry through maturation. Scale chemistry accurately reflected trace element composition of the water in which fish had lived. Juvenile spot (Leiostomus xanthurus) were held in four concentrations of Sr, Cd, and Ba maintained at either 20°C or 25°C, for 42 days. Strontium:Ca, Cd:Ca, and Ba:Ca levels in scales were linearly related to environmental concentrations while temperature had no effect. …

Pfiesteria Piscicida And Dinoflagellates Similar To Pfiesteria, Harold G. Marshall

Virginia Journal of Science

Pfiesteria pisiccida is a microscopic, unicellular organism that is classified as both a mixotrophic and heterotrophic dinoflagellate, which has been associated with both fish deaths and a cause of human illness (Burkholder et al., 1992; Glasgow et al., 1995; Burkholder and Glasgow, 1997). This species possesses a complex life cycle that includes motile forms (e.g. zoospores, gametes, amoebae) and a cyst stage that may remain dormant in the sediment (Burkholder et al., 1995b). Pfiesteria piscicida is known to have toxin and non-toxin producing populations, where cyst transformation into the toxic motile zoospores may be initiated by the presence of certain …

Modeling The Msx Parasite In Eastern Oyster (Crassostrea Virginica) Populations. Iii. Regional Application And The Problem Of Transmission, Eric N. Powell, John M. Klinck, Susan E. Ford, Eileen E. Hofmann, Stephen J. Jordon

CCPO Publications

A model of transmission for Haplosporidium nelsoni, the disease agent for MSX disease, is developed and applied to sites in Delaware Bay and Chesapeake Bay. The environmental factors that force the oyster population- H. nelsoni model are salinity, temperature, food, and total suspended solids. The simulated development of MSX disease was verified using 3 time series of disease prevalence and intensity: 1960 to 1970 and 1980 to 1990 for Delaware Bay, and 1980 to 1994 for Chesapeake Bay, and for a series of sites covering the salinity gradient in each bay. Additional simulations consider the implications of assumptions made …

Modeling The Msx Parasite In Eastern Oyster (Crassostrea Virginica) Populations. Ii. Salinity Effects, Michelle C. Paraso, Susan E. Ford, Eric N. Powell, Eileen E. Hofmann, John M. Klinck

CCPO Publications

An oyster population model coupled with a model for Haplosporidium nelsoni, the causative agent of the oyster disease MSX, was used with salinity time-series constructed from Delaware River flow measurements to study environmentally-induced variations in the annual cycle of this disease in Delaware Bay oyster populations. Model simulations for the lower Bay (high salinity) sire reproduced the annual cycle observed in lower Delaware Bay. Simulations at both upper Bay (low salinity) and lower Bay sites produced prevalences and intensities that were consistent with field observations. At all sites, low freshwater discharge resulted in increased disease levels, whereas high freshwater …

Modeling The Msx Parasite In Eastern Oyster (Crassostrea Virginica) Populations. I. Model Development, Implementation, And Verification, Susan Ford, Eric Powell, John Klinck, Eileen Hofmann

CCPO Publications

A mathematical model simulating the host-parasite-environmental interactions of eastern oysters (Crassostrea virginica) and the pathogen, Haplosporidium nelsoni, which causes MSX disease, has been developed. The model has 2 components. One replicates the infection process within the oyster and the other simulates transmission. The infection-development component relies on basic physiological processes of both host and parasite, modified by the environment, to reproduce the observed annual prevalence cycle of H. nelsoni. Equations describing these rates were constructed using data from long-term field observations, and field and laboratory experiments. In the model, salinity and temperature have direct effects upon …

Growth And Yield-Per-Recruit Modeling Of Spot (Leiostomus Xanthurus) In The Chesapeake Bay, And A Comparison Of Biological Reference Points, Kevin Ray Piner

Biological Sciences Theses & Dissertations

Spot were sampled from the Chesapeake Bay commercial fishery from 1993–1995 to determine if spot are overfished. Transversely sectioned otoliths were determined to be the most appropriate structure for ageing spot. It was determined that spot have a high natural mortality rate (M = 0.9) and fast growth (K = 0.6). This combination of M and K makes spot relatively impervious to growth overfishing as determined by yield-per-recruit modeling. Because spot are nearly impervious to growth overfishing, management thresholds based on yield-per-recruit modeling may be inappropriate. In addition, the combination of high M and fast K makes it possible to …

Radiocarbon From Nuclear Testing Applied To Age Validation Of Black Drum, Pogonias Cromis, Steven E. Campana, Cynthia M. Jones

OES Faculty Publications

Radiocarbon ((14)C) in the world's oceans increased sharply between 1950 and 1970 as a result of the atmospheric testing of nuclear weapons. Through comparison with the (14)C time series reconstructed from atmospheric measurements and marine carbonates, Kalish, in 1993, used the (14)C concentration measured in fish otolith cores as a means of confirming the annulus-based age estimates for some South Pacific fish species. Here we report the pre-and postbomb (14)C chronology of North Atlantic adult black drum (Pogonias cronis), assumed to be between 15 and 42 yr of age on the basis of otolith annulus counts. According to …

Modeling Environmental Effects On Msx Prevalence And Intensity In Eastern Oyster (Crassostrea Virginica) Populations, Michelle Christine Paraso

OES Theses and Dissertations

An oyster population model coupled with a model for Haplosporidium nelsoni, the causative agent of the oyster disease MSX, was used with salinity time-series constructed from Delaware River flow measurements to study environmentally-induced variations in the annual cycle of this disease. Simulations with this model were designed to investigate the effect of increased or decreased spring freshwater discharge, the timing of high freshwater runoff, the presence or absence of a fall or late spring phytoplankton bloom, and the occurrence of a warm winter on MSX prevalence and intensity in Delaware Bay oyster populations. Model simulations for the lower Bay site …