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Full-Text Articles in Life Sciences
Color Image-Analyzed Fluorescence Microscopy: A New Tool For Marine Microbial Ecology, Ml Sieracki, Cl Viles
Color Image-Analyzed Fluorescence Microscopy: A New Tool For Marine Microbial Ecology, Ml Sieracki, Cl Viles
VIMS Articles
BACTERIA, cyanobacteria, protozoa and small eukaryotic phytoplankton are now known to be funda- mental components of marine planktonic ecosystems (Azam et al., 1983; Sieburth, 1984). These organisms have high potential growth rates, are efficient convert- ers of material and energy, and usually constitute most of the plankton biomass (Davis et al., 1985; Fuhrman et al., 1989). Their different trophic levels are often closely coupled. These characteristics require that experimental and sampling designs for studying the microbial populations incorporate appropriate (i.e., small) temporal and spatial scales. The corollary to this is that large numbers of samples must be taken. If these …
Systematics Of The Pearlfishes (Pisces, Carapidae), Df Markle, Je Olney
Systematics Of The Pearlfishes (Pisces, Carapidae), Df Markle, Je Olney
VIMS Articles
A review of taxonomy, anatomy, ontogeny, ecology, and phylogeny of the ophidiiform family Carapidae was conducted using over 2,300 larval, juvenile and adult specimens. A cladistic classification based on swimbladder morphology, developmental and osteological characters of the vertebral column, fins, pectoral and pelvic girdles, gill arches, ethmoid, jaws, and habitat is presented. A total of 31 species (6 new names and one unnamed larval form) in seven genera are recognized in two subfamilies. A species previously assigned to Echiodon is made the type of a new monotypic genus. Species of the tribe Carapini are rearranged in the genera Carapus and …
Small-Scale Organism Distributions And Patterns Of Species Diversity: Evidence For Positive Interactions In An Estuarine Benthic Community, Linda C. Schaffner
Small-Scale Organism Distributions And Patterns Of Species Diversity: Evidence For Positive Interactions In An Estuarine Benthic Community, Linda C. Schaffner
VIMS Articles
No abstract provided.
Utilization Of Marsh And Seagrass Habitats By Early Stages Of Callinectes-Aapidus - A Latitudinal Perspective, R J. Orth, J Van Montfrans
Utilization Of Marsh And Seagrass Habitats By Early Stages Of Callinectes-Aapidus - A Latitudinal Perspective, R J. Orth, J Van Montfrans
VIMS Articles
Seagrass beds and marshes have been identified as important nurseries for the blue crab, Callinectes sapidus. This nursery paradigm is based on blue crab abundance data from trawl, seine and drop-net sampling that has revealed greater abundances in these habitats than in adjacent unvegetated areas. Recently, more quantitative and intensive sampling in seagrass beds and marshes over broad latitudinal scales, combined with manipulative experiments, indicate that the same habitat may vary in utilization on regional scales. Mechanisms accounting for enhanced abundances in these nursery habitats have not been elucidated from a latitudinal perspective. Regional comparisons of blue crab catch data …
Seasonal Composition Of Finfish In Waters Behind The Virginia Barrier Islands, Brenda L. Norcross, David Hata
Seasonal Composition Of Finfish In Waters Behind The Virginia Barrier Islands, Brenda L. Norcross, David Hata
VIMS Articles
Semi-monthly sampling of finfish was conducted in the lagoons and marshes behind Parramore and Cedar Islands at Wachapreague Inlet, Cobb and Wreck Islands at Sand Shoal Inlet, and on the northwest side of Fisherman Island from September 1986 through September 1987. Although all lifestages were collected, the study was designed to focus on utilization of this area by juvenile finfish. Sixty-nine species offinfish were collected. Species diversity and abundance fluctuated widely among seasons. Both were highest in the fall and lowest in the winter. The most abundant species over all seasons and locations were silversides (Menidia menidia) and bay anchovy …
Blue-Crab Population-Dynamics In Chesapeake Bay - Variation In Abundance (York River, 1972-1988) And Stock-Recruit Functions, Rom Lipcius, Wa Van Engel
Blue-Crab Population-Dynamics In Chesapeake Bay - Variation In Abundance (York River, 1972-1988) And Stock-Recruit Functions, Rom Lipcius, Wa Van Engel
VIMS Articles
Blue crab abundance in the York River, Virginia was analyzed for interannual, monthly and spatial variation at two stations sampled by bottom trawl from 1972-1988. Various stock-recruitment and recruit-stock functions were derived from trawl abundance and commercial fishery landings statistics. The key component of variation was due to interannual fluctuations in abundance, which remained consistently high or low for two or more years before changing, suggesting internal population feedback mechanisms, such as cannibalism, or long-term climatic control. In addition, significant cyclic patterns in residuals from stockrecruitment functions further indicated the existence of long-term variability in abundance. Peak seasonal abundance and …
Utilization Of A Seagrass Meadow And Tidal Marsh Creek By Blue Crabs Callinectes-Sapidus Ii. Spatial And Temporal Patterns Of Molting, Ch Ryer, J Van Montfrans, Rj Orth
Utilization Of A Seagrass Meadow And Tidal Marsh Creek By Blue Crabs Callinectes-Sapidus Ii. Spatial And Temporal Patterns Of Molting, Ch Ryer, J Van Montfrans, Rj Orth
VIMS Articles
Blue crabs were collected weekly from a lower Chesapeake Bay seagrass meadow and adjacent tidal marsh creek over 2 months (July-August 1987) and molt staged. Molting activity, determined from a total of I ,220 crabs, was greater in the grassbed than in the marsh creek, and greater for small crabs and females. The difference between the two habitats in molting activity decreased from the first to the second month of sampling, possibly in response to seasonal decline in seagrass biomass. The proportion of small (<70 mm) females in both habitats was greatest on full moons. There was a lunar rhythm of molting activity by large crabs (2:70 mm), with peak molting activity on fuIl moons. SmaIl crabs demonstrated a similar, but nonsignificant rhythm of molting. We suggest that blue crabs approaching ecdysis aggregate in seagrass meadows, taking advantage of the refuge from predation that this structurally complex habitat affords. Lunar rhythmicity of molting activity may further reduce predation mortality through a dilution effect.
Foraging Behavior Of The Blue-Crab, Callinectes-Sapidus, On Juvenile Oysters, Crassostrea-Virginica - Effects Of Prey Density And Size, Db Eggleson
VIMS Articles
Blue crabs (Callinectes sapidus) are major predators of juvenile oysters (Crassostrea virginica) in Chesapeake Bay, yet little information exists on the foraging behavior and predatorprey dynamics for this predator-prey system. Laboratory experiments assessed functional responses of blue crabs to six densities of three size-classes of juvenile American oysters. Behavioral subcomponents of the crabs' functional response were quantified: total and successful encounter rates, proportional attack success, persistence time in unsuccessful encounters, and breaking, eating and handling times in successful encounters. Specific opening techniques were used by crabs for the three oyster size-classes. Blue crabs exhibited a hyperbolic type II functional response …
Molting In The Mature Female Blue-Crab, Callinectes-Sapidus Rathbun, Kirk J. Havens, Jr Mcconaugha
Molting In The Mature Female Blue-Crab, Callinectes-Sapidus Rathbun, Kirk J. Havens, Jr Mcconaugha
VIMS Articles
The present study examined the hypothesis that mature female blue crabs, Callinectes sapidus, do not enter a terminal anecdysis. Induced molting via eyestalk ablation, size frequency distributions, gonad development and limb regeneration indices from field collected animals are used as indicators of potential post maturity molts. Eyestalk ablation of 15mature females resulted in ecdysis in II individuals approximately 51 days (standard error = 0.64) after ablation, indicating a physiological ability of mature females to complete ecdysis. Analysis of size frequency distributions from catch data indicated two distinct shifts from smaller to larger females, one in early spring and a second …
Daily, Monthly And Annual Settlement-Patterns By Callinectes-Sapidus And Neopanope-Sayi Megalopae On Artificial Collectors Deployed In The York River, Virginia - 1985-1988, J Van Montfrans, Ca Peery, R J. Orth
Daily, Monthly And Annual Settlement-Patterns By Callinectes-Sapidus And Neopanope-Sayi Megalopae On Artificial Collectors Deployed In The York River, Virginia - 1985-1988, J Van Montfrans, Ca Peery, R J. Orth
VIMS Articles
Daily, monthly and annual settlement of dominant brachyuran megalopae on six replicate artificial settlement substrates (collectors) was examined at one site in the York River, Virginia, from mid-July or early August to early December during 1985-1988. Callinectes sapidus Rathbun, an exported estuarine species, and Neopanope sayi (Smith), a retained estuarine species, were the numerically dominant colonizers of collectors. C. sapidus settlement was highly episodic (l-3-day duration) and significantly associated with the full moon period (lunar day 15-22). The temporal mean of settlement for C. sapidus each year fell within a 12-day period (24 September-6 October) over the 4 years. C. …
Settlement Patterns Of Crassostrea Virginica (Gmelin, 1791) Larvae In Relation To Tidal Zonation, G. Curtis Roegner, Roger L. Mann
Settlement Patterns Of Crassostrea Virginica (Gmelin, 1791) Larvae In Relation To Tidal Zonation, G. Curtis Roegner, Roger L. Mann
VIMS Articles
Experiments were conducted to determine the settlement distribution of the oyster Crassostrea virginica (Gmelin) in relation to tidal zonation in an area where adult populations are largely confined to the intertidal zone. Hatchery-reared pediveliger larvae were interned in PVC tubes positioned at known tidal heights. The influence of non-tidal factors was limited: mesh covering the ends of the tubes prevented loss of larvae to dispersal or predation, the settling substrate was not colonized by competitors, and the effects of light and horizontal currents were minimized. Settlement was found to occur throughout the intertidal zone but predominated at the bottom of …
Shelter Scaling Regulates Survival Of Juvenile Caribbean Spiny Lobster Panulirus Argus, Db Eggleston, Rom Lipcius, Dl Miller, L Cobacetina
Shelter Scaling Regulates Survival Of Juvenile Caribbean Spiny Lobster Panulirus Argus, Db Eggleston, Rom Lipcius, Dl Miller, L Cobacetina
VIMS Articles
No abstract provided.
Planktonic Availability, Molt Stage And Settlement Of Blue Crab Postlarvae, Rom Lipcius, Ej Olmi, J Van Montfrans
Planktonic Availability, Molt Stage And Settlement Of Blue Crab Postlarvae, Rom Lipcius, Ej Olmi, J Van Montfrans
VIMS Articles
No abstract provided.
Variation In Planktonic Availability And Settlement Of Blue-Crab Megalopae In The York River, Virginia, Ej Olmi, J Van Montfrans, Rn Lipcius, R J. Orth, Pw Sadler
Variation In Planktonic Availability And Settlement Of Blue-Crab Megalopae In The York River, Virginia, Ej Olmi, J Van Montfrans, Rn Lipcius, R J. Orth, Pw Sadler
VIMS Articles
Blue crab, Callinectes sapidus, megalopae and juveniles were sampled in the plankton and on natural (grassbeds) and artificial settlement substrates (collectors) at two sites in each of two areas of a lower Chesapeake Bay tributary (York River, Virginia) to examine spatial variability in blue crab recruitment. Spatial patterns of abundance were not consistent across habitats (plankton, artificial collectors and grassbeds) or time. Densities of planktonic megalopae were homogeneous at 1-2 m (within site) but varied at spatial scales of hundreds of meters (between sites) and kilometers (between areas). Settled megalopae were distributed unevenly within and between sites, but their abundance …
Automated Enumeration By Computer Digitization Of Age-0 Weakfish Cynoscion Regalis Scale Circuli, Stephen T. Szedlmayer, Margaret M. Szedlmayer, Michael E. Sieracki
Automated Enumeration By Computer Digitization Of Age-0 Weakfish Cynoscion Regalis Scale Circuli, Stephen T. Szedlmayer, Margaret M. Szedlmayer, Michael E. Sieracki
VIMS Articles
There has been extensive use of daily otolith growth increments in age and growth ·studies of age-O fishes (Campana and Neilson 1985). Recently, the daily ageing method has been extended to scales (Szedlmayer et al. In press). However, visually counting increments is tedious, time consuming, and subject to human error (Rice 1987). In an effort to automate the counting of increments or daily circuli in scales of age-O juvenile weakfish Cynoscion regalis, a microcomputer-based system was used to digitize the video image of a scale, store the light intensities from a radial transect, and count circuli.