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- Keyword
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- Biological Sciences Peer-Reviewed Articles (15)
- Fisheries Science Peer-Reviewed Articles (5)
- Physical Sciences Peer-Reviewed Articles (4)
- Aquatic Health Sciences Peer-Reviewed Articles (2)
- Amphipods; complexity; cover; dimensionless index; Fundulus heteroclitus; habitat structure; Paleomonetes spp. (1)
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- Chesapeake Bay (1)
- Cogradient variation; countergradient variation; foraging; growth; natural selection; Littorina obtusata; plasticity; predation; wave energy (1)
- Conservation; blue crab; Callinectes sapidus; spawning stock; recruitment; larval abundance; exploitation (1)
- Crassostrea Gigas; Crassostrea Ariakensis; Diploid; Hybrid; Tetraploid; Oyster; Breeding; Polyploidy (1)
- Crassostrea Gigas; Sperm Motility; Ph; Caffeine; Osmotic Pressure; Tetraploid; Cryopreservation (1)
- Data assimilation; modeling; estuary; Chesapeake Bay; salinity (1)
- Ecosystem model; hydrodynamic processes; feedback controls; York River estuary (1)
- Gradient Gel-Electrophoresis; Polymerase Chain-Reaction; Ribosomal-RNA Gene; Class Proteobacteria (1)
- Habitat degradation; hypoxia; dissolved oxygen; stratification; hydrography; benthos; Macoma spp. (1)
- Haplosporidium Costale; Eastern Oyster; Crassostrea Virginica; In Situ Hybridization; Long Island Sound (1)
- Photosynthesis; diatoms; Phaeocystis; accessory pigments (1)
- Rapa Whelk; Rapana Venosa; Hard Clam; Mercenaria Mercenaria; Predation; Chesapeake Bay (1)
- Sediment; suspension; diffusion; advection; turbulence; Duck; North Carolina (1)
- Seeds; seagrass; predation; Posidonia australis; Western Australia; tether (1)
- Squid; estuaries; salinity; water temperature; dissolved oxygen; Lolliguncula brevis (1)
- Stranding ; cetaceans; marine mammals (1)
- USA; eelgrass; long-distance dispersal; marine macrophyte; seagrass ecology; spatial ecology; Zostera marina (1)
- Withering Syndrome; Black Abalone; Haliotis; Rickettsiales; "Candidatus Xenohaliotis Californiensis" (1)
- York River estuary; size-structured phytoplankton and nutrient dynamics; ecosystem simulation model; controlling mechanisms; advection and diffusion (1)
- Zooplankton; vertical migration; gut evacuation rate; gut fluorescence; particulate organic carbon; particulate organic nitrogen; export flux; Sargasso sea; Bermuda Atlantic time-series study (BATS) (1)
- Zostera; Spartina; blue crab; post-larvae; juvenile instars; post-larvae; survival (1)
Articles 1 - 26 of 26
Full-Text Articles in Life Sciences
Long-Distance Dispersal Potential In A Marine Macrophyte, Mc Harwell, R J. Orth
Long-Distance Dispersal Potential In A Marine Macrophyte, Mc Harwell, R J. Orth
VIMS Articles
Plant populations have long been noted to migrate faster than predicted based on their life history and seed dispersal characteristics (i.e., Reid's paradox of rapid plant migration). Although precise mechanisms to account for such phenomena are not fully known for all plant species, a combination of theoretical and empirically driven mechanisms often resolves this paradox. Here, we couple a series of direct and indirect field and laboratory exercises on one marine macrophyte, Zostera marina L. (eelgrass), to measured distances between new patches and established beds in order to elucidate the longdistance dispersal and colonization potential of this marine seagrass. Detached, …
A Perspective On Two Decades Of Policies And Regulations Influencing The Protection And Restoration Of Submerged Aquatic Vegetation In Chesapeake Bay, Usa, R J. Orth, Ra Batiuk, Pw Bergstrom, Ken Moore
A Perspective On Two Decades Of Policies And Regulations Influencing The Protection And Restoration Of Submerged Aquatic Vegetation In Chesapeake Bay, Usa, R J. Orth, Ra Batiuk, Pw Bergstrom, Ken Moore
VIMS Articles
Seagrasses along with many other species of freshwater rooted submerged macrophytes in Chesapeake Bay (collectively called SAV) underwent serious declines in population abundances in the 1970s and have not as yet rebounded to previous levels. Cooperative efforts by scientists, politicians, federal and state resource managers, and the general public have developed policies and plans to protect, preserve and enhance SAV populations of Chesapeake Bay. These include the Chesapeake Bay Agreements (1983, 1987, 1992, 1993, 2000), an SAV Management Policy and Implementation Plan for Chesapeake Bay and Tidal Tributaries (1989 and 1990), Chesapeake Bay Blue Crab Fishery Management Plan (1997), as …
The Magnitude Of Spring Bacterial Production In The North Atlantic Ocean, Hw Ducklow, Dl Kirchman, Tr Anderson
The Magnitude Of Spring Bacterial Production In The North Atlantic Ocean, Hw Ducklow, Dl Kirchman, Tr Anderson
VIMS Articles
Dissolved organic carbon (DOC), a major reservoir in the ocean carbon cycle, is produced by a profusion of plankton sources and processes but is consumed mainly by bacterioplankton. Thus bacterial metabolism regulates the entry of DOC into the longer scale global carbon cycle. Bacterial production (BP) is the routinely measured quantity for evaluating the roles of bacteria in carbon cycling. However BP cannot be measured directly and instead is estimated from related metabolic processes requiring the use of poorly constrained conversion factors. BP and thus the total carbon utilization, are potentially uncertain by a factor of two or more. In …
The Microbial And Metazoan Community Associated With Colonies Of Trichodesmium Spp.: A Quantitative Survey, Cc Sheridan, Deborah K. Steinberg, Gw Kling
The Microbial And Metazoan Community Associated With Colonies Of Trichodesmium Spp.: A Quantitative Survey, Cc Sheridan, Deborah K. Steinberg, Gw Kling
VIMS Articles
Association with resource-rich particles may benefit a number of planktonic species in oligotriphic, open-ocean regimes. This study examined communities of microbes and Zooplankton associated with colonies of the cyanobacterium Trichodesmium spp. in the Sargasso Sea. Trichodesmium colonies and seawater controls were collected near Bermuda using SCUBA during September 1995, and June, July and August 1996. Organisms associated with the colonies and those in the surrounding seawater were enumerated using light and fluorescence microscopy. We found that 85% of the Trichodesmium puff and tuft colonies examined harbored associated organisms. Associated organisms included bacteria (rod and coccoid),fungi, pennate diatoms, centric diatoms, heterotrophic …
Observations On The Distribution Of Meroplankton During A Downwelling Event And Associated Intrusion Of The Chesapeake Bay Estuarine Plume, Al Shanks, J Largier, L Brink, J Brubaker, R Hooff
Observations On The Distribution Of Meroplankton During A Downwelling Event And Associated Intrusion Of The Chesapeake Bay Estuarine Plume, Al Shanks, J Largier, L Brink, J Brubaker, R Hooff
VIMS Articles
We investigated the dispersal of larvae of benthic invertebrates and tested the hypothesis that larvae behaved as if they were passive particles. Observations were made off Duck, North Carolina, USA diving a period of wind driven downwelling at the coast and an intrusion of estuarine water from the Chesapeake Bay. The plume of estuarine water (salinity < 30 psu) was strongest at the shoreward stations in the more northern transects. Wind driven shoreward surface flow, converged at the seaward edge of the plume and downwelled. Offshore flow was present below the thermocline and caused the thermocline to bend downward and contact the bottom at between 5 and 10 km offshore. In the zooplankton samples, we enumerated 33 taxa of larvae (17 taxa of bivalve veligers, 10 taxa of gastropod veligers, and 6 taxa of polychaete larvae). Using cluster analysis, larvae were separated into groups with similar patterns of distribution. If larvae were acting as passive particles then we hypothesized that: 1) Their distribution should remain tied to a water mass and 2) around a convergence or divergence, there should be no change in larval concentration. The distributions of larvae in Clusters 1, 4, 5, and 6 were consistent with the hypothesis that thy were acting as passive particles. Larvae in Clusters 2 and 3, however, did not appear to be acting as passive particles. Larvae in Cluster 2 did not remain tied to a water mass. They entered the study area in the estuarine plume waters, but within 20 km they were nearly absent from the plume water and were found seaward of the plume and at greater depth. Larvae in Cluster 3 were most abundant in areas of converging currents where the shoreward flowing surface waters downwelled at the plume front or against the shore. We hypothesized that larvae of organisms which as adults live in the intertidal or shallow, subtidal zones would have more nearshore distributions than the larvae of adults that are broadly distributed across the shelf. We compared the depth of the habitat of the adult bivalves from which the bivalve larvae in the different clusters were derived. The results were consistent with the hypothesis; larvae with distributions closer to shore tended to come from adults found at shallower depths or in the intertidal zone.
Widespread Distribution In Polar Oceans Of A 16s Rrna Gene Sequence With Affinity To Nitrosospira-Like Ammonia-Oxidizing Bacteria, Jt Hollibaugh, Hw Ducklow, N Bano
Widespread Distribution In Polar Oceans Of A 16s Rrna Gene Sequence With Affinity To Nitrosospira-Like Ammonia-Oxidizing Bacteria, Jt Hollibaugh, Hw Ducklow, N Bano
VIMS Articles
We analyzed the phylogenetic compositions of ammonia-oxidizing bacteria of the beta subclass of Proteobacteria from 42 Southern Ocean samples. We found a Nitrosospira-like 16S rRNA gene sequence in all 20 samples that yielded PCR products (8 of 30 samples from the Ross Sea and 12 of 12 samples from the Palmer Peninsula). We also found this sequence in Arctic Ocean samples, indicating a transpolar, if not global, distribution; however, slight differences between Arctic and Antarctic sequences may be evidence of polar endemism.
Distribution Of The Euryhaline Squid Lolliguncula Brevis In Chesapeake Bay: Effects Of Selected Abiotic Factors, Ik Bartol, Roger L. Mann, M Vecchione
Distribution Of The Euryhaline Squid Lolliguncula Brevis In Chesapeake Bay: Effects Of Selected Abiotic Factors, Ik Bartol, Roger L. Mann, M Vecchione
VIMS Articles
The majority of cephalopods are thought to have limitations arising from physiology and locomotion that exclude them from shallow, highly variable, euryhaline environments. The brief squid Lolliguncula brevis may be a notable exception because it tolerates low salinities, withstands a wide range of environmental conditions, and swims readily in shallow water. Little is known about the distribution of L. brevis in Chesapeake Bay, a diverse and highly variable estuary. Therefore, a survey of L. brevis was conducted in the Virginia portion of Chesapeake Bay from 1993 to 1997 using a 9.1 m otter trawl, and the effects of selected factors …
Assimilating High-Resolution Salinity Data Into A Model Of A Partially Mixed Estuary, Jiangtao Xu, Shenn-Yu Chao, Raleigh R. Hood, Harry V. Wang
Assimilating High-Resolution Salinity Data Into A Model Of A Partially Mixed Estuary, Jiangtao Xu, Shenn-Yu Chao, Raleigh R. Hood, Harry V. Wang
VIMS Articles
[1] A three-dimensional circulation model of the Chesapeake Bay is used to validate a simple data assimilation scheme, using high-resolution salinity data acquired from a ship-towed undulating vehicle (a Scanfish). The simulation period spans the entire year of 1995 during which the high-resolution Scanfish data were available in July and October, lasting a few days each. Since Scanfish data were irregularly distributed in time and space, only salinity fields are nudged in the model for simplicity. Model improvements through data assimilation are evaluated from a pair of experiments: one with data assimilation and one without. Data from scattered Chesapeake Bay …
Estimating The Spatial Extent Of Bottom-Water Hypoxia And Habitat Degradation In A Shallow Estuary, Cp Buzzelli, Ra Luettich, Sp Powers, Ch Peterson, Je Mcninch, Jl Pinckney, Hw Paerl
Estimating The Spatial Extent Of Bottom-Water Hypoxia And Habitat Degradation In A Shallow Estuary, Cp Buzzelli, Ra Luettich, Sp Powers, Ch Peterson, Je Mcninch, Jl Pinckney, Hw Paerl
VIMS Articles
Bottom-water hypoxia (less than or equal to2 mg l(-1) dissolved oxygen [DO]) greatly modifies the benthic habitat of estuaries, depending upon spatial extent, duration, and frequency. Bottom-water hypoxia often develops under conditions of density stratification, which inhibits vertical mixing, and warm temperatures, which enhance biological oxygen demand. Long-term, mid-channel data from the Neuse River Estuary in North Carolina permitted evaluation of how stratification and temperature combined to affect DO concentrations at the bottom. Salinity stratification (AS) and water temperature (T) explained respectively 30 and 23 % of the variance in bottom-water DO concentrations. The amount of salinity stratification required to …
Factors Affecting Sperm Motility Of Tetraploid Pacific Oysters, Qx Dong, B Eudeline, Standish K. Allen Jr., Tr Tiersch
Factors Affecting Sperm Motility Of Tetraploid Pacific Oysters, Qx Dong, B Eudeline, Standish K. Allen Jr., Tr Tiersch
VIMS Articles
Factors such as osmotic pressure, extender solution, addition of caffeine, and pH have been shown to affect sperm motility in aquatic species. We evaluated the effects of 18 osmotic pressures, two extender solutions, seven caffeine concentrations, and a pH range of 3 to 14 on motility of sperm from tetraploid Pacific oysters, Crassostrea gigas. Motility was highest at 1000 mOsmol/kg (mean +/- SD: 83 +/- 14%). Calcium-free Hanks' balanced salt solution yielded significantly higher sperm motility than did artificial seawater. Sperm motility increased with caffeine concentrations to 20 mM (81 +/- 12%) and decreased when concentrations were higher than 50 …
Rapa Whelk Rapana Venosa (Valenciennes, 1846) Predation Rates On Hard Clams Mercenaria Mercenaria (Linnaeus, 1758), D Savini, Jm Harding, Roger L. Mann
Rapa Whelk Rapana Venosa (Valenciennes, 1846) Predation Rates On Hard Clams Mercenaria Mercenaria (Linnaeus, 1758), D Savini, Jm Harding, Roger L. Mann
VIMS Articles
The recent discovery of adult veined rapa whelks Rapana venosa (Valenciennes, 1846) in the Lower Chesapeake Bay, U.S.A. offers cause for both ecological and economic concern. Adult rapa whelks are large predatory gastropods that consume bivalves including commercially valuable species such as hard clams, Mercenaria mercenaria (Linnaeus, 1758). Laboratory feeding experiments were used to estimate daily consumption rates of two sizes of whelks feeding on two size classes of hard clams. Large rapa whelks (shell length, SL > 101 mm) are capable of consuming up to 2.7 g wet weight of clam tissue daily, equivalent to 0.8% of their body weight. …
Transmission Of Withering Syndrome In Black Abalone, Haliotis Cracherodii Leach, Cs Friedman, W Biggs, Jeffrey D. Shields, Rp Hedrick
Transmission Of Withering Syndrome In Black Abalone, Haliotis Cracherodii Leach, Cs Friedman, W Biggs, Jeffrey D. Shields, Rp Hedrick
VIMS Articles
Withering syndrome (WS) has been associated with catastrophic declines in black abalone populations in southern and central California. In an effort to identify the etiological agent of WS and to characterize the progression of this disease, we initiated a transmission study in which abalone from Ano Nuevo Island, a location free of WS, shared aquaria with animals from Vandenberg Airforce Base, a location where WS is epizootic. The mean incubation period of WS (time to develop overt signs of the disease) was 245 days with a mean time to death after development of clinical signs of 42 days. Median time …
Haplosporidium Costale (Seaside Organism), A Parasite Of The Eastern Oyster, Is Present In Long Island Sound, I Sunila, Na Stokes, R Smolowitz, Rc Karney, E. M. Burreson
Haplosporidium Costale (Seaside Organism), A Parasite Of The Eastern Oyster, Is Present In Long Island Sound, I Sunila, Na Stokes, R Smolowitz, Rc Karney, E. M. Burreson
VIMS Articles
A haplosporidian parasite, Haplosporidium costale (seaside organism or SSO), is associated with high mortalities of eastern oysters (Crassostrea virginica) in seaside bays of Virginia and Maryland. Its presence in Long Island Sound has been tentatively suggested in several publications for the last 50 y. Positive identification of H. costale and differentiation from another haplosporidian parasite, Haplosporidium nelsoni (MSX), from histological sections is difficult and requires the presence of spores. We detected H. costale spores in 4 out of 5010 (0.08%) oysters collected from Long Island Sound in 1997-1999. In situ hybridization using an oligonucleotide DNA probe designed to detect small …
Hybridization Of Tetraploid And Diploid Crassostrea Gigas (Thunberg) With Diploid C-Ariakensis (Fujita), H Que, Standish K. Allen Jr.
Hybridization Of Tetraploid And Diploid Crassostrea Gigas (Thunberg) With Diploid C-Ariakensis (Fujita), H Que, Standish K. Allen Jr.
VIMS Articles
Three replicates of hybrid crosses of tetraploid and diploid C gigas (Thunberg) with diploid C ariakensis (Fujita) were produced with controls. Larval survival and growth were documented. Cytological events were also monitored in oocytes from hybrid crosses following insemination. Among the four types of hybrid crosses, diploid C. gigas (female) x diploid C. ariakensis (male) (GA) was the most successful. Survival of GA was about the same as that of controls in two of three replications, although its growth rate was 25-30% lower. Crosses of tetraploid C. gigas (female) and diploid C. ariakensis (male) (GGA) had poor yield at day …
Examination Of Diffusion Versus Advection Dominated Sediment Suspension On The Inner Shelf Under Storm And Swell Conditions, Duck, North Carolina, Guan-Hong Lee, Carl T. Friedrichs, Chris E. Vincent
Examination Of Diffusion Versus Advection Dominated Sediment Suspension On The Inner Shelf Under Storm And Swell Conditions, Duck, North Carolina, Guan-Hong Lee, Carl T. Friedrichs, Chris E. Vincent
VIMS Articles
[1] A benthic boundary layer tripod supporting six current meters and three profiling acoustic backscatter sensors (ABS) documented storm and swell conditions during the fall of 1996 at a depth of 13 m on the inner shelf off Duck, North Carolina. Sediment concentration was higher in the wave boundary layer (WBL) during storm conditions but higher similar to40 cm above the bed (cm ab) during swell conditions. To test the applicability of a diffusive balance during storm versus swell, ABS data were used to invert the vertical diffusion equation and solve for eddy diffusivity from 1 to 50 cm ab. …
Across-Shelf Sediment Transport: Interactions Between Suspended Sediment And Bed Sediment, Courtney K. Harris, Patricia Wiberg
Across-Shelf Sediment Transport: Interactions Between Suspended Sediment And Bed Sediment, Courtney K. Harris, Patricia Wiberg
VIMS Articles
[1] We use a two-dimensional, time-dependent sediment-transport model to quantify across-shelf transport, deposition, and sorting during wave-driven resuspension events characteristic of those that dominate sediment transport on many continental shelves. Decreases in wave-orbital velocities as water depth increases, and the resulting cross-shelf gradient in bed shear stress favor a net offshore transport of sediment. On wide, flat shelves (slopes similar to0.1%), these gradients are low, and the depth to which the seabed is reworked depends mainly on bottom shear stress and local sediment availability. On narrow, steep shelves (slopes similar to0.5%), however, the gradient in bottom stress generates significant cross-shelf …
Predation On Seeds Of The Seagrass Posidonia Australis In Western Australia, R J. Orth, Kl Heck, Dj Tunbridge
Predation On Seeds Of The Seagrass Posidonia Australis In Western Australia, R J. Orth, Kl Heck, Dj Tunbridge
VIMS Articles
Despite much evidence that predation governs seed abundance, and ultimately seedling and adult plant distribution and abundance in terrestrial ecosystems, there is a dearth of information from seagrass dominated ecosystems. We report here on the first study to examine predation rates from seeds of Posidonia australis measured during field tethering experiments at 5 locations in Western Australia. Seeds that were recently dehisced from ripe fruits and at a similar stage of development were tethered in seagrass and adjacent unvegetated sand for 24 h and then assessed for damage. Seed predation was noted at all sites and ranged from partially to …
Evidence Of Countergradient Variation In The Growth Of An Intertidal Snail In Response To Water Velocity, Gc Trussell
Evidence Of Countergradient Variation In The Growth Of An Intertidal Snail In Response To Water Velocity, Gc Trussell
VIMS Articles
Growth rates in rocky intertidal snails can vary considerably across wave exposure gradients, and have both plastic and genetic bases. However, little is known regarding whether genetic and environmental influences on variation in growth act in the same (cogradient) or in an opposing (countergradient) direction. Determining how genetic and environmental influences on growth covary with one another may improve our understanding of how habitat-specific variation in growth emerges. This study utilized laboratory flumes to examine the effects of high and low water velocities on the growth of intertidal snails Littorina obtusata from a wave-exposed and a sheltered shore. Both flow …
Active Transport Of Particulate Organic Carbon And Nitrogen By Vertically Migrating Zooplankton In The Sargasso Sea, A Schnetzer, Deborah K. Steinberg
Active Transport Of Particulate Organic Carbon And Nitrogen By Vertically Migrating Zooplankton In The Sargasso Sea, A Schnetzer, Deborah K. Steinberg
VIMS Articles
Diel vertically migrating zooplankton can contribute significantly to dissolved carbon and nutrient export by respiring and excreting surface-ingested particulate organic matter below the mixed layer. Active export of particulate organic carbon (POC) and particulate organic nitrogen (PON) due to defecation at depth has rarely been considered in export budgets. We measured the gut passage time (GPT) of common migrant species at the Bermuda Atlantic Time-series Study (BATS) site, using the gut fluorescence method, to determine whether GPT is slow enough to allow active export of POC and PON to depth. Mean GPT for the copepods Pleuromamma xiphias and Euchirella messinensis …
Habitat Quality And Prey Size As Determinants Of Survival In Post-Larval And Early Juvenile Instars Of The Blue Crab Callinectes Sapidus, R J. Orth, J Van Montfrans
Habitat Quality And Prey Size As Determinants Of Survival In Post-Larval And Early Juvenile Instars Of The Blue Crab Callinectes Sapidus, R J. Orth, J Van Montfrans
VIMS Articles
Habitat structure and prey size are important determinants in the outcome of predator-prey interactions. We investigated the role of simulated habitat type and density (simulated Zostera marina [hereafter referred to as 'Zostera']: 500 and 1500 shoots m(-2), and simulated Spartina alterniflora [hereafter referred to as 'Spartina']: 97 and 291 shoots m(-2)) in mediating predator-prey interactions. Proportional survival during predation by the piscene predator Fundulus heteroclitus on 2 successive life-history stages (post-larvae and first juvenile instars) of the blue crab Callinectes sapidus (Rathbun), was quantified under laboratory conditions that closely approximated field conditions. We also examined the effects of juvenile crab …
Ecosystem Modeling Analysis Of Size-Structured Phytoplankton Dynamics In The York River Estuary, Virginia (Usa). I. Development Of A Plankton Ecosystem Model With Explicit Feedback Controls And Hydrodynamics, Y Sin, Rl Wetzel
VIMS Articles
An ecosystem simulation model was developed to investigate potential mechanisms controlling the size-structured phytoplankton and nutrient dynamics in the mesohaline zone of the York River estuary. The model included 12 state variables in a unit volume (m(3)) describing the distribution of carbon and nutrients (nitrogen, phosphorus) in the surface mixed layer. General size-scale relationships and density-dependent feedback control terms were used in the ecosystem model. Forcing functions included incident solar radiation, water temperature, wind stress, river flow and tide, which include advective transport and turbulent mixing. Advective transport and turbulent mixing were incorporated into the model explicitly without coupling to …
Ecosystem Modeling Analysis Of Size-Structured Phytoplankton Dynamics In The York River Estuary, Virginia (Usa). Ii. Use Of A Plankton Ecosystem Model For Investigating Controlling Factors On Phytoplankton And Nutrient Dynamics, Y Sin, Rl Wetzel
VIMS Articles
An ecosystem simulation model was used to investigate potential mechanisms controlling the size-structured phytoplankton and nutrient dynamics in the mesohaline zone of the York River estuary, The York River ecosystem model (Sin & Wetzel 2001, Mar Ecol Prog Ser 228:75-90)was calibrated and validated based on field observations and laboratory measurements prior to the exercises reported here. Analyses of model sensitivity to state variable changes and parameter variations were performed to examine hypotheses proposed from previous studies regarding controls on phytoplankton and nutrient dynamics in the York River estuary. The model results supported the general view that phytoplankton dynamics may be …
Total Cover And Cover Quality: Predicted And Actual Effects On A Predator's Foraging Success, A Bartholomew
Total Cover And Cover Quality: Predicted And Actual Effects On A Predator's Foraging Success, A Bartholomew
VIMS Articles
I tested the importance of both total cover and cover quality to the foraging ability of large Fundulus heteroclitus fish in tanks. Total cover was measured as the combined areas of all the individual structures, viewed as shadows. I divided total cover by the bottom area of the tank to form C-t/A(t), an index that measures the total amount of structure available in a given area for prey to hide behind. Cover quality was measured as the width of each individual structure divided by the width of the individual prey organism (C-w/P-w). This index measures how visible a prey organism …
Concurrent Decline Of The Spawning Stock, Recruitment, Larval Abundance, And Size Of The Blue Crab Callinectes Sapidus In Chesapeake Bay, Rom Lipcius, Wt Stockhausen
Concurrent Decline Of The Spawning Stock, Recruitment, Larval Abundance, And Size Of The Blue Crab Callinectes Sapidus In Chesapeake Bay, Rom Lipcius, Wt Stockhausen
VIMS Articles
Conservation of exploited marine populations requires knowledge of interannual variation in the characteristics of and relationships between the spawning stock and recruitment, which determine Population resilience and persistence. We examined relationships between spawning stock abundance, postlarval recruitment, larval abundance, and female size of the blue crab in Chesapeake Bay, both within the Spawning grounds over a 13 yr interval (1988 to 2000) and within lower-bay tributaries over 20 yr (1979 to 1998). Our findings establish that there has been a concurrent, persistent and substantial reduction in the spawning stock, recruitment, larval abundance, and female size, Specifically, in 1992 to 2000: …
Photo Synthesis/Irradiance Relationships In The Ross Sea, Antarctica, And Their Control By Phytoplankton Assemblage Composition And Environmental Factors, C. M. Van Hilst, Walker O. Smith Jr.
Photo Synthesis/Irradiance Relationships In The Ross Sea, Antarctica, And Their Control By Phytoplankton Assemblage Composition And Environmental Factors, C. M. Van Hilst, Walker O. Smith Jr.
VIMS Articles
The photosynthetic parameters of natural phytoplankton assemblages from the Ross Sea, Antarctica, as well as unialgal cultures of the diatom Pseudonitzschia sp. and the colonial haptophyte Phaeocystis antarctica were investigated to determine if differential responses to irradiance could explain the distribution of phytoplankton in the Ross Sea. Field assemblages had photosynthetic responses that suggested acclimation to low irradiance levels, and the initial rate of photosynthesis per unit chlorophyll (a) and the theoretical maximum rate of production (p(max)(B)) averaged 0,083 mg C (mg chl a)(-1) h(-1) (mumol m(-2) s(-1))(-1) and 2,40 mg C (mg chl a)(-1) h(-1), respectively. An increase in …
Temporal And Geographic Occurrences Of Cetacean Strandings And Manatee Sightings In Virginia, With Notes On Adverse Human-Cetacean Interactions, From 1983-1989, Lee W. Morgan, John A. Musick, Charles W. Potter
Temporal And Geographic Occurrences Of Cetacean Strandings And Manatee Sightings In Virginia, With Notes On Adverse Human-Cetacean Interactions, From 1983-1989, Lee W. Morgan, John A. Musick, Charles W. Potter
VIMS Articles
From 1 January 1983 to 31 December 1989, 416 cetacean strandings consisting of five families and 15 species, and five manatee sightings were recorded in Virginia waters. Most records were of bottlenose dolphins, Tursiops truncatus (339, 1.3%). Most cetacean strandings were reported from Virginia Beach (230, 55.1 % ). The highest number of strandings occurred in 1987 (265, 63.5%) when an epizootic killed many Tursiops. There were five confirmed sightings of manatees in Virginia waters during the study period. Thirty-four stranded cetaceans showed signs of adverse interactions related to human activities.