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A Profile Of The Oyster Industry Northeastern United States, Douglas Lipton, James Kirkley

Reports

This is a critical period for the future of the east coast oyster industry. This report documents the dramatic decline in industry output which has been the impetus for a publicly funded program to "revtalize" the industry. Oyster biologists argue over the severityy of the decline and the cause, and also the potential remedies. Should non-native oysters, specifically Crassostrea gigas, be introduced into the region to replace the native oyster production? Are there ways to manage around the devastating oyster diseases MSX and Dermo? Will large populations of oysters significantly improve the water quality in currentiy degraded areas?

While these …

Campus Of Virginia Institute Of Marine Science, School Of Marine Science, The College Of William And Mary, Virginia Institute Of Marine Science

Miscellaneous

No abstract provided.

Survival Of Juvenile Caribbean Spiny Lobster: Effects Of Shelter Size, Geographic Location And Conspecific Abundance, Jd Mintz, Rom Lipcius, Db Eggleson, Ms Seebo

VIMS Articles

The Caribbean spiny lobster Panulirus argus seeks structured shelter throughout its benthic phase, often forming aggregations within shelters. Casitas - concrete, low-relief, artificial shelters - are effective in aggregating lobsters, and are used to harvest spiny lobster in the Caribbean. However, casitas may also enhance populations of P. argus, by providing shelter from predation. In this study we examined the effects of various shelter features upon the survival of juvenile P. argus. Juvenile lobsters were tethered at several artificial shelter treatments in Florida Bay, Florida, USA, to test the efficacy of casitas as refuge from predation. Survival of juveniles was …

Interannual Variation In The Recruitment Pattern And Abundance Of Age-0 Summer Flounder, Paralichthys-Dentatus, In Virginia Estuaries, Brenda L. Norcross, David M. Wyanski

VIMS Articles

Capture of transforming larval and newly settled juvenile (age-0) summer flounder, Paralichthys dentatus, over four years (1986-1989) in the seaside salt marshes of Virginia's Eastern Shore and in the lower Chesapeake Bay verifies Virginia waters as a nursery area. Gear specific for juvenile flatfish was used and sampling was conducted in a broad range of habitats in all months. This study demonstrates a fluctuation in the timing of the appearance and magnitude of abundance of age-0 summer flounder in Virginia waters over a four-year sampling period. Age-0 summer flounder (11-27 mm TL) began entering the area in October 1986 and …

Experimental Monitoring Of Virginia Artificial Reefs Using Fishermen Catch Data, Ja Lucy, Cg Barr

VIMS Articles

Catch and effort data were compiled in 1987-1988 from recreational fishing trips targeting artificial reefs and other structure sites in Virginia waters. Data were collected from boat-owning fishermen by a random telephone survey. Within target species groups, catch rates were compared among five fishing sites inside Chesapeake Bay and two offshore reefs. Fishermen's target species options were more diverse at estuarine (bay) sites, primarily the result of Sciaenidae species (Leiostomus xanthurus, Micropogonias undulatus, and Cynoscion regalis) and Paralichthys dentatus. The Gwynn's Island Test Reef, closest to mid-bay, provided significantly higher mean catch rates of L. xanthurus in 1988 than lower …

Quantifying Seasonal-Variation In Somatic Tissue - Surfclam Spisula-Solidissima (Dillwyn, 1817) - A Case-Study, Joseph G. Loesch, David A. Evans

VIMS Articles

Condition indexes are commonly derived from bivalve species. Usable meat yields (UMY, in l/bu) from 181 daily landings of Atlantic surfclams, Spisula solidissima (Dellwyn, 1817), at a Virginia processing plant in 1974 and 160 landings in 1975 were used as an index in our analysis. The data were fitted to a basic sinusoidal model and a two-compartment sinusoidal model to demonstrate the utility of these models for quantifying cyclic events. The basic model, x = x(0) + A cos2 pi t + B sin2 pi t, is linear in its independent variables and fitted by multiple regression, with x = …

Technical Efficiency, Biological Considerations, And Management And Regulation Of The Sea-Scallop, Placopecten-Magellanicus (Gmelin, 1791) Fishery, James E. Kirkley, William D. Dupaul

VIMS Articles

Achieving social and economic efficiency in a fishery requires that production be technically efficient. Yet, technical efficiency (TE) is rarely examined for a fishery. By the use of detailed trip-level data and information about resource conditions obtained from routine sampling, a stochastic frontier production model relating landings to days at sea, crew size, and resource conditions is specified and estimated for 10 Mid-Atlantic sea scallop (Placopecten magellanicus) dredge vessels. TE is shown to depend partly on the mix of controllable inputs such as days at sea and crew size but possibly more on uncontrollable factors such as resource conditions and …

Reproductive Activity Of Oysters, Crassostrea-Virginica (Gmelin, 1791) In The James River, Virginia, During 1987-1988, Roger L. Mann, Julia S. Rainer, Reinaldo Morales-Alamo

VIMS Articles

Reproductive activity in oysters, Crassostrea virginica Gmelin, in the James River, Virginia, was examined for 1987 from weekly estimates for fecundity and egg viability in oysters collected from Wreck Shoal, and for 1988 from weekly estimates of fecundity, egg viability, gonad volume fraction, gonad thickness, and mean egg size in oysters collected from Horsehead Reef. Maximum and mean fecundity values from Wreck Shoal oysters were higher than from Horsehead oysters. No relationship was evident between fecundity and egg viability at Horsehead Reef. A strong temporal relationship was observed between egg viability and peak oyster settlement in the James in both …

A Comparison Of A Validated Otolith Method To Age Weakfish, Cynoscion-Regalis, With The Traditional Scale Method, Luiz R. Barbieri, Mark E. Chittenden, Susan K. Lowerre-Barbieri

VIMS Articles

Otoliths, scales, dorsal spines, and pectoral-fin rays were compared to ascertain the best hardpart for determining the age of weakfish, Cynoscion regalis. Each showed concentric marks, which could be interpreted as annuli. Sectioned otoliths, however, consistently showed the clearest marks, had 100% agreement between and within readers, and were validated by the marginal increment method for ages 1-5. This validated method of ageing weakfish was then compared with the traditionally used scale method. The scale method was less precise, as demonstrated by lower percent agreement, and generally assigned younger ages for fish older than age 6 (as determined by otoliths). …

Morphometric And Genetic Identification Of Eggs Of Spring-Spawning Sciaenids In Lower Chesapeake Bay, Louis B. Daniel Iii, John Graves

VIMS Articles

Restriction-fragment length polymorphism (RFLP) analysis of mitochondrial mtDNA was used to identify morphologically similar eggs of spring spawning sciaenids in lower Chesapeake Bay. During spring 1990 and 1991, ichthyoplankton surveys were conducted in lower Chesapeake Bay to estimate seasonal egg production and population biomass of black drum, Pogonias cromis. Rearing experiments indicated that at least three species of sciaenid (silver perch, Bairdiella chrysoura; weakfish, Cynoscion regalis and P. cromis) were spawning in the survey area during both years. Specific identification of eggs based on previously published ranges of outside egg diameter (OED) were not reliable because of considerable overlap in …

Vertical Migration Of Blue Crab Callinectes Sapidus Megalopae: Implications For Transport In Estuaries, Ej Olmi

VIMS Articles

Following larval development in coastal waters, postlarvae (megalopae) of the blue crab Callinectes sapidus Rathbun enter inlets and, against the net seaward flow of estuarine waters, move upstream to juvenile habitats. Abundance and vertical distribution of blue crab megalopae in the York River, Virginia, USA, a subsetuary of Chesapeake Bay, was quanitified to examine the hypothesis that megalopae are not transported simply as passive particles, but display behaviors that augment their immigration. Megalopal abundance and depth distribution and environmental variables were measured at shallow (3 to 4 m) sites in 1988 and 1989 and at a deep (10 m) site …

Description Of Metamorphic Phases In The Oyster Crassostrea Virginica And Effects Of Hypoxia On Metamorphosis, Sm Baker, Roger L. Mann

VIMS Articles

Four phases of metamorphosis in the eastern oyster Crassostrea virginica were characterized:'settlers' have attached to the substrate but retain larval characteristics; metamorphosis and degeneration of the velum has begun in 'prodissoconch postlarvae'; in 'dissoconch postlarvae' shell growth beyond the prodissoconch has begun but the foot persists; and 'juveniles' have lost all larval organs and metamorphosis is complete. These phases were used in examining the metamorphic process during and following continuous and short-term exposures to hypoxia (1.5 mg O-2 l(-1), 20 % of air saturation) and microxia (< 0.07 mg O(2)l(-1), < 1 % of air saturation). We observed no abnormal development in the oysters, but development was delayed following 3 d exposures to hypoxia, and 2 and 3 d exposures to microxia. Under continuous exposure to microxia, oysters did not develop to the dissoconch postlarva or juvenile phases. Approximately 50 % of the control oysters died within the 2 wk period following settlement. Morality was virtually confined to the settler and prodissoconch postlarva phases. Short-term exposures to hypoxia (1 to 3 d) and microxia (1 d) had little effect on the median mortality time or final total mortality, compared to controls. Microxic treatments longer than 1 d did affect mortality and oysters continuously exposed to microxia had a median mortality time of 87 h. Short-term exposures to low oxygen did not have permanent effects on post-settlement growth rates. Oysters exposed to microxic treatments, however, appeared to have slower growth rates during the exposure period. We conclude that low oxygen conditions, in particular those that are microxic and last longer than 24 h, have detrimental effects on the development, growth, and mortality of post settlement oysters.

Maturity, Spawning, And Ovarian Cycle Of Atlantic Croaker, Micropogonias-Undulatus, In The Chesapeake Bay And Adjacent Coastal Waters, Luiz R. Barbieri, Mark E. Chittenden, Susan K. Lowerre-Barbieri

VIMS Articles

The reproductive biology of Atlantic croaker, Micropogonias undulatus, collected during 1990-91 from commercial catches in Chesapeake Bay and in Virginia and North Carolina coastal waters (n=3,091), was studied by using macroscopic and microscopic gonad staging, the gonadosomatic index, oocyte diameter distributions, and histological analysis. Atlantic croaker are multiple spawners with asynchronous oocyte development and indeterminate fecundity. Mean length at first maturity for males and females was 182 and 173 mm TL, respectively. More than 85% of both sexes were mature by the end of their first year and all were mature by age 2. Spawning extends over a protracted period …

Paddlefish Buccal Flow Velocity During Ram Suspension Feeding And Ram Ventilation, S. Laurie Sanderson, Joseph Cech Jr, A Y. Cheer

Arts & Sciences Articles

A micro-thermistor probe was inserted into the buccal cavity of freely swimming paddlefish to measure flow velocity during ram ventilation, ram suspension feeding and prey processing. Swimming speed was measured from videotapes recorded simultaneously with the buccal flow velocity measurements. Both swimming velocity and buccal flow velocity were significantly higher during suspension feeding than during ram ventilation. As the paddlefish shifted from ventilation to feeding, buccal flow velocity increased to approximately 60 % of the swimming velocity. During prey processing, buccal flow velocity was significantly higher than the swimming velocity, indicating that prey processing involves the generation of suction. The …

The In-Vitro Life-Cycle Of A Perkinsus Species (Apicomplexa, Perkinsidae) Isolated From Macoma-Balthica (Linneaus, 1758), Sj Kleinschuster, Fo Perkins, Mj Dykstra, Sl Swink

VIMS Articles

Using standard sterile techniques and a single medium previously described (Kleinschuster and Swink 1993), the in vitro culture of a Perkinsus species isolated from Macoma balthica was possible. Zoosporulation, the release of zoospores, and the reestablishment of secondary cultures from the zoospores completed an in vitro life cycle.

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, Cynthia M. Jones

VIMS Articles

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. No …

In-Vitro And In-Vivo Effects Of 8 Chemotherapeutants On The Oyster Parasite Perkinsus-Marinus (Mackin, Owen, And Collier), Gustavo W. Calvo, Eugene M. Burreson

VIMS Articles

Eight therapeutants were tested for in vitro inhibition of Perkinsus marinus (Mackin, Owen, and Collier) enlargement and in vivo control of established infections. In addition, acute toxicity of six anticoccidials to oysters was determined. For in vitro experiments 0.2 ml aliquots of infected hemolymph were exposed to 5 concentrations (100 mg/l, 10 mg/l, 1 mg/l, 0.1 mg/l and 0.01 mg/1) of amprolium, arprinocid, cycloheximide, lasalocid, malachite green, monensin, sulfadimethoxine, and a potentiated sulfadimethoxine. Exposure lasted 1 day and was followed by incubation in fluid thioglycollate medium. Lasalocid and malachite green were the most effective compounds, showing significant anti-P. marinus activity …

Characterization Of Overwintering Infections Of Perkinsus-Marinus (Apicomplexa) In Chesapeake Bay Oysters, Lisa M. Ragone Calvo, Em Burreson

VIMS Articles

To determine the nature and abundance of over-wintering P. marinus infections, infected oysters (Crassostrea virginica) collected from the upper James River, VA, were placed in a tray and suspended from a pier in the lower York River, VA in November 1991. Every six weeks through May 1992 oysters (n = 25) were removed from the tray, examined for P. marinus by hemolymph culture in fluid thioglycollate medium (FTM), gradually warmed in individual containers to 25-degrees-C and held for one month. After the incubation period, which permitted the development of very light and/or cryptic parasite stages to detectable levels, the oysters …

Growth And Mortality Of Eastern Oysters, Crassostrea-Virginica (Gmelin, 1791), And Pacific Oysters, Crassostrea-Gigas (Thunberg, 1793) Under Challenge From The Parasite, Perkinsus-Marinus, Bruce J. Barber, Roger L. Mann

VIMS Articles

Stocks of oysters Crassostrea virginica and C. gigas were produced in the Virginia Institute of Marine Science (VIMS) hatchery in April 1991 and grown in two quarantined flumes receiving water from the York River, VA. From July 1991 through November 1992, growth and mortality of both species were compared. Also, beginning in June 1992 one flume (containing one group of each species) was ''dosed'' (oysters infected with P. marinus added) and the other flume remained ''undosed'' (no infected oysters added). Disease prevalence and intensity, mortality, and shell height were compared both within (between undosed and dosed groups) and between species. …

Aerobic And Anaerobic Degradation And Mineralization Of C-14 Chitin By Water Column And Sediment Inocula Of The York-River-Estuary, Virginia, Jn Boyer

VIMS Articles

Potential rates of chitin degradation (C(d)) and mineralization (C(m)) by estuarine water and sediment bacteria were measured as a function of inoculum source, temperature, and oxygen condition. In the water column inoculum, 88 to 93% of the particulate chitin was mineralized to CO2 with no apparent lag between degradation and mineralization. No measurable dissolved pool of radiolabel was found in the water column. For the sediment inocula, 70 to 90% of the chitin was degraded while only 55 to 65% was mineralized to CO2. C-14 label recoveries in the dissolved pool were 19 to 21% for sand, 17 to 24% …

Comparison Of Infectivity And Pathogenicity Of Meront (Trophozoite) And Prezoosporangiae Stages Of The Oyster Pathogen Perkinsus-Marinus In Eastern Oysters, Crassostrea-Virginica (Gmelin, 1791), Aswani Volety, Fu-Lin E. Chu

VIMS Articles

Two experiments were conducted to compare the infectivity and pathogenicity of two life stages of the parasite Perkinsus marinus, meronts (trophozoites) and prezoosporangia (hypnospores), in eastern oysters, Crassostrea virginica. Oysters were inoculated with 5 X 10(4) meronts or prezoosporangia per oyster by injection into the shell cavity. Prevalence and intensity of P. marinus infections, condition index, serum protein concentrations, and lysozyme activities were measured in oysters after 15, 25, 40, and 65 days in experiment 1 and after 20, 40, 50, 65, and 75 days postchallenge by P. marinus cells in experiment 2. Controls were injected with filtered York River …

Age, Growth Rate, Sexual Dimorphism And Fecundity Of Knobbed Whelk Busycon Carica (Gmelin, 1791) In A Western Mid-Atlantic Lagoon System, Virginia, Micheal Castagna, John H. Kraeuter

VIMS Articles

Growth, onset of sexual maturity, and sexual reversal in laboratory-reared Busycon carica have been examined. Animals first matured at 9 years of age. The first sign of maturity in all animals we reared was the presence of the penis. At 12.4 years of age, one of the animals laid an egg case that did not contain embryos. This animal, and all others, still retained a penis. At 13.5 years, three egg cases were laid and over half the animals had undergone sex reversal (loss of the penis). Field studies have shown that egg strings are laid in the fall on …

A Physiological Approach To The Understanding Of Parasite (Perkinsus Marinus) Interactions : Pathological Effects And Disease Resistance, Bruce Barber, Roger L. Mann

Reports

No abstract provided.

By-Catch And The Fishery For Atlantic Menhaden (Brevoortia Tyrannus) In The Mid-Atlantic Bight An Assessment Of The Nature And Extent Of By-Catch, Herb Austin, James Kirkley, Jon Lucy

Reports

No abstract provided.

Sycamore Platanus Occidentalis L., Gene Silberhorn

Reports

The Wetland Flora Technical Report series provides concise information regarding the identification, growth habits, distribution, habitat, ecology and wetland indicator status for the title species. Illustrations are also included to aid in specimen identification.

The Status Of Virginia's Public Oyster Resource 1993, Reinaldo Alonzo-Morales, Roger Mann

Reports

This report summarizes data collected during 1993 in the Virginia portion of the Chesapeake Bay. The report is composed of two parts, part one, oyster recruitment (shell string) in Virginia and part two, dredge survey of selected oyster bars in Virginia.

Evidence For A Relation Between A White Perch Young-Of-The-Year Index And Indices Of Later Life Stages, Thomas C. Mosca Iii, Herbert Austin, David M. Plotner

Reports

Juvenile indices are employed in fisheries management to predict the future relative abundance of harvestable adults and to monitor the success of management efforts. Frequently, regulations controlling utilization of the resource, and a lack of fishery independent abundance data, make verification of the prediction impossible. In the case of white perch (Morone americana) in Virginia, this is not so. Using the weighting system developed for a Chesapeake Bay-wide index of juvenile striped bass abundance based on summertime beach seine data collected in nursery ground waters, we developed a similar index for white perch in the Virginia portion of the Bay. …

Economic Impact Of Marine Aquaculture On Virginia's Eastern Shore, Sayra Thacker

Reports

No abstract provided.

Restoration Of The Virginia Oyster Fishery The Alternative Species Strategy, Dennis Taylor

Reports

No abstract provided.

Rally Round! A Guide To Environmental Action Projects For Grades 4-7, Virginia Bay Team, Sea Grant Marine Advisory Program

Reports

No abstract provided.