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Full-Text Articles in Life Sciences

Perkinsus-Marinus (Apicomplexa) As A Potential Source Of Oyster Crassostrea-Virginica Mortality In Coastal Lagoons Of Tabasco, Mexico, Em Burreson, Rs Alvarez, W Martinez, La Macedo Oct 1994

Perkinsus-Marinus (Apicomplexa) As A Potential Source Of Oyster Crassostrea-Virginica Mortality In Coastal Lagoons Of Tabasco, Mexico, Em Burreson, Rs Alvarez, W Martinez, La Macedo

VIMS Articles

Poorly documented, but apparently sporadic oyster Crassostrea virginica mortality in the coastal lagoons Carmen, Machona and Mecoacan at the southern extreme of the Gulf of Mexico in Tabasco, Mexico, has been attributed by local oystermen to pollution resulting from oil refinery operations. In September 1992 we sampled oysters in these lagoons to investigate the potential for disease-induced mortality from the oyster pathogen Perkinsus marinus. Prevalence of P. marinus was 100% at Lodazal, a high salinity (31 ppt) site in Carmen lagoon and 60% at Rio San Felipe, a low salinity (15 ppt) site. At Los Jimenez, a high salinity (32 …


Hematodinium-Australis N-Sp, A Parasitic Dinoflagellate Of The Sand Crab Portunus-Pelagicus From Moreton Bay, Australia, Da Hudson, Jeffrey D. Shields Jul 1994

Hematodinium-Australis N-Sp, A Parasitic Dinoflagellate Of The Sand Crab Portunus-Pelagicus From Moreton Bay, Australia, Da Hudson, Jeffrey D. Shields

VIMS Articles

A new species of parasitic dinoflagellate is described from the portunid crab Portunus pelagicus. The dinoflagellate is a member of the genus Hematodinium which formerly consisted of a single species, H. perezi. Members of the genus have been reported in crabs and lobsters from Europe and North America, where in some circumstances they cause significant mortalities to host populations. The new species is the first member of the family Syndinidae to be fully described from Australia. The new species differs from other forms of Hematodinium primarily by the size of the trophont (vegetative stage), the ovoid plasmodium, and the small …


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 Jan 1994

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 …


Survival Of Juvenile Caribbean Spiny Lobster: Effects Of Shelter Size, Geographic Location And Conspecific Abundance, Jd Mintz, Rom Lipcius, Db Eggleson, Ms Seebo Jan 1994

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 Jan 1994

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 …


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 Jan 1994

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 …


Experimental Monitoring Of Virginia Artificial Reefs Using Fishermen Catch Data, Ja Lucy, Cg Barr Jan 1994

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 …


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 Jan 1994

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 Jan 1994

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 …