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Full-Text Articles in Life Sciences
Estimation Of Relative Abundance Of Recreationally Important Finfish In The Virginia Portion Of Chesapeake Bay: Annual Progress Report 2000-2001, Patrick J. Geer, Herbert M. Austin
Estimation Of Relative Abundance Of Recreationally Important Finfish In The Virginia Portion Of Chesapeake Bay: Annual Progress Report 2000-2001, Patrick J. Geer, Herbert M. Austin
Reports
Several annual indices of juvenile abundance have been generated from trawl survey data for species of key recreational importance in the Virginia portion of Chesapeake Bay (spot, croaker, weakfish, summer flounder, black sea bass and striped bass, white and channel catfish) and four species of secondary importance (scup, white perch, northern puffer, and silver perch). No species has shown a continuous trend during the past fourteen years under the present sampling scheme. However, several species have revealed declines (spot, scup, and northern puffer) or increases (striped bass) in recent years. Results for the 2000 sampling season indicate significant declines over …
Density-Dependent Predation, Habitat Variation, And The Persistence Of Marine Bivalve Prey, Rochelle D. Seitz, Rom Lipcius, Ah Hines, Db Eggleston
Density-Dependent Predation, Habitat Variation, And The Persistence Of Marine Bivalve Prey, Rochelle D. Seitz, Rom Lipcius, Ah Hines, Db Eggleston
VIMS Articles
The persistence of prey encountering intense predation varies by species, prey density, and habitat type; however, the collective impact of these factors has rarely been tested experimentally in natural marine systems. Using the thin-shelled clams Mya arenaria and Macoma balthica as prey, and the main epibenthic predator of whole adult clams, the blue crab Callinectes sapidus, we conducted a series of experiments in Chesapeake Bay tributaries that (1) links field abundance and distribution of bivalve prey species with habitat-specific mortality patterns; (2) represents the first comprehensive field test of species-specific, habitat-specific, and density-dependent mortality for subtidal, soft-bottom, deep-burrowing prey; and …
Habitat Fragmentation In A Seagrass Landscape: Patch Size And Complexity Control Blue Crab Survival, Ka Hovel, Rom Lipcius
Habitat Fragmentation In A Seagrass Landscape: Patch Size And Complexity Control Blue Crab Survival, Ka Hovel, Rom Lipcius
VIMS Articles
Habitat fragmentation is increasingly common on land and in the sea, leading to small, isolated habitat patches in which ecological processes may differ substantially from those in larger, continuous habitats. Seagrass is a productive but fragmented subtidal habitat that serves as a refuge from predation for many animals because its structural complexity limits the detection and capture of resident prey. The singular influence of seagrass habitat fragmentation (e.g., patch size) on faunal survival is largely unknown and has been difficult to quantify because seagrass habitat complexity (e.g., shoot density) and patch size are often confounded and vary seasonally. In early …
Variation In Top-Down And Bottom-Up Control Of Marine Bivalves At Differing Spatial Scales, Rochelle D. Seitz, Rom Lipcius
Variation In Top-Down And Bottom-Up Control Of Marine Bivalves At Differing Spatial Scales, Rochelle D. Seitz, Rom Lipcius
VIMS Articles
At large spatial scales(> 1 km). the forces structuring marine communities are diverse and include oceanographic, geological. and human processes, as well as availability of regional species pools. Few studies in marine and estuarine systems have examined the joint effects of predation (top-down) and food availability (bottom-up) in controlling populations at these scales. We compared the relative influence of top-down and bottom-up factors to population abundance of the infaunal clam Macomala balthican in two ecosystems differing in spatial extent by an order of magnitude. the York River, 50 km long, and the Rhode River. 5 km long. In both rivers, …
Reproduction And Food Habits Of The Lined Seahorse, Hippocampus Erectus (Teleostei: Syngnathidae) Of Chesapeake Bay, Virginia., R. L. Teixeira, John A. Musick
Reproduction And Food Habits Of The Lined Seahorse, Hippocampus Erectus (Teleostei: Syngnathidae) Of Chesapeake Bay, Virginia., R. L. Teixeira, John A. Musick
VIMS Articles
The reproductive and feeding biology of the lined seahorse, Hippocampus erectus, was studied inChesapeake Bay. Seahorses are monogamous, and males incubate the eggs received from femalesin a closed brood pouch (= marsupium). Females do not play any parental care after mating. Totalsex ratio and the operational sex ratio was strongly skewed toward females. Males and females hadsimilar number of eggs/embryos and hydrated oocytes, respectively. The number of eggs/embryosfound in the male brood pouch varied from 97 to 1,552 (fish from 80 to 126 mm TL), whereas thenumber of hydrated oocytes in female varied from 90 to 1,313 (fish from 60 …
Restoration Of The Oyster Resource In Chesapeake Bay: The Role Of Oyster Reefs In Population Enhancement, Water Quality Improvement And Support Of Diverse Species-Rich Communities, Roger L. Mann
VIMS Articles
Restoration of the oyster Crassostrea virginica resource to the Chesapeake Bay is a widely supported goal. The role of the oyster in restoration through benthic-pelagic coupling is examined in the context of current and projected watershed management problems, agricultural and urban development with associated nutrient and sediment erosion issues, in the entire Chesapeake Bay watershed. Efforts to date have focused on rebuilding three-dimensional reef structures, often with oyster broodstock enhancement, in predominantly small estuaries with retentive circulation to provide demonstration of increased resultant recruitment. Fishery enhancement activity is then based on local increases in recruitment. Such examples are used to …
The Effects Of A Regulatory Gear Restriction On The Recruiting Year Class In The Sea Scallop, Placopecten Magellanicus (Gmelin, 1791), Fishery, Jc Brust, Wd Dupaul, Je Kirkley
The Effects Of A Regulatory Gear Restriction On The Recruiting Year Class In The Sea Scallop, Placopecten Magellanicus (Gmelin, 1791), Fishery, Jc Brust, Wd Dupaul, Je Kirkley
VIMS Articles
In 1994, Amendment 4 to the sea scallop (Placopecten magellanicus) fishery management plan was adopted, which restricted fishing effort by controlling vessel days at sea. crew size, and gear size. Dredge ring size was increased from 76.2 mm (3.0") to 82.6 mm (3.25") in March 1994, and again to 88.9 mm (3.5") in January 1996 to increase the age of entry of scallops into the fishery. Between June 1994 and April 1995, four trips were taken on commercial scallop vessels in the western mid-Atlantic to determine harvest efficiency of 88.9-mm dredge rings relative to 82.6-mm dredge rings used in the …
A Comparison Of Calcified Structures For Aging Summer Flounder, Paralichthys Dentatus, Ann M. Sipe, Mark E. Chittenden
A Comparison Of Calcified Structures For Aging Summer Flounder, Paralichthys Dentatus, Ann M. Sipe, Mark E. Chittenden
VIMS Articles
Calcified structures of summer flounder, Paralichthys dentatus, were evaluated to identify the best age determination method. Scales, the currently preferred structure, were compared with opercular bones and to right and left whole and sectioned otoliths for ages 0 to 10. All structures showed concentric rings that were interpreted as annual; however structures differed greatly in the clarity of their presumed annual marks. Right and left otoliths generally gave the same age, although they differed in the clarity of marks. Sectioned otoliths, particularly right ones, were the best aging structure. Right sectioned otoliths consistently showed the clearest marks and had the …
Aerobic Respiratory Costs Of Swimming In The Negatively Buoyant Brief Squid Lolliguncula Brevis, Ian K. Bartol, Roger L. Mann, Mark R. Patterson
Aerobic Respiratory Costs Of Swimming In The Negatively Buoyant Brief Squid Lolliguncula Brevis, Ian K. Bartol, Roger L. Mann, Mark R. Patterson
VIMS Articles
Because of the inherent inefficiency of jet propulsion, squid are considered to be at a competitive disadvantage compared with fishes, which generally depend on forms of undulatory/oscillatory locomotion. Some squid, such as the brief squid Lolliguncula brevis, swim at low speeds in shallow-water complex environments, relying heavily on fin activity. Consequently, their swimming costs may be lower than those of the faster, more pelagic squid studied previously and competitive with those of ecologically relevant fishes. To examine aerobic respiratory swimming costs, O2 consumption rates were measured for L. brevis of various sizes (2–9 cm dorsal mantle length, DML …
Criteria For Determining Maturity Stage In Female American Shad, Alosa Sapidissima, And A Proposed Reproductive Cycle, Je Olney, Sc Denny, Jm Hoenig
Criteria For Determining Maturity Stage In Female American Shad, Alosa Sapidissima, And A Proposed Reproductive Cycle, Je Olney, Sc Denny, Jm Hoenig
VIMS Articles
We describe macro- and microscopic criteria to judge maturation stages of female American shad (Alosa sapidissima) collected in the York river, Virginia, USA. For comparison, we also examined ovaries of fishes collected in the Edisto river, South Carolina, and the Connecticut river, Massachusetts. The study augments a developing stock assessment program that is evaluating the use of index-removal and change-in-ratio estimators of exploitation rate and absolute abundance. Samples were obtained from traps at the York river mouth, staked gill nets in mid-reaches of the river, and drift gill nets on the spawning grounds (approximately 100 km from the river mouth). …
Oyster Reefs As Fish Habitat: Opportunistic Use Of Restored Reefs By Transient Fishes, Juliana M. Harding, Roger L. Mann
Oyster Reefs As Fish Habitat: Opportunistic Use Of Restored Reefs By Transient Fishes, Juliana M. Harding, Roger L. Mann
VIMS Articles
Under the Magnuson-Stevenson Fisheries Management Act of 1996, current fisheries management practice is focused on the conce_pt of Essential Fish Habitat (EFH). Application of the EFH concept to estuarine habitats relates directly to ongoing oyster reef restorat10n efforts. Oyster reef restoration typically creates complex habitat in regions where such habitat is limited or absent. While healthy oyster reefs provide structurally and ecologically complex habitat for many other species from all trophic levels including recreationally and commercially valuable transient finfishes, additional data is required to evaluate oyster reef habitats in the context of essential fish habitat. Patterns of transient fish species …
Swimming Mechanics And Behavior Of The Shallow-Water Brief Squid Lolliguncula Brevis, Ian K. Bartol, Mark R. Patterson, Roger L. Mann
Swimming Mechanics And Behavior Of The Shallow-Water Brief Squid Lolliguncula Brevis, Ian K. Bartol, Mark R. Patterson, Roger L. Mann
VIMS Articles
Although squid are among the most versatile swimmers and rely on a unique locomotor system, little is known about the swimming mechanics and behavior of most squid, especially those that swim at low speeds in inshore waters. Shallow-water brief squid Lolliguncula brevis, ranging in size from 1.8 to 8.9 cm in dorsal mantle length (DML), were placed in flumes and videotaped, and the data were analyzed using motion-analysis equipment. Flow visualization and force measurement experiments were also performed in water tunnels. Mean critical swimming speeds (Ucrit) ranged from 15.3 to 22.8 cm s–1 …
Fishing Skill In Developing Country Fisheries: The Kedah, Malaysia Trawl Fishery, K. Kuperan Viswanathan, Ishak Haji Omar, Yongil Jeon, James Kirkley, Et Al
Fishing Skill In Developing Country Fisheries: The Kedah, Malaysia Trawl Fishery, K. Kuperan Viswanathan, Ishak Haji Omar, Yongil Jeon, James Kirkley, Et Al
VIMS Articles
Fishing skillis perceived to play a crucial role in catching fish. The
question arises for fishery managers as to whether or not there are observable
and measurable attributes of the skipper or vessel hat can be monitored and
regulated to account for skipper skill and, hence,this source of fishing capacity.
Equating technical efficiency with skipper skill, this paper evaluates technical
efficiency and skipper skill in the Kedah, Malaysia,trawl fishery to address this
issue.
Seasonal Occurrence And Site-Utilization Patterns Of Adult Tautog, Tautoga Onitis (Labridae), At Manmade And Natural Structures In Lower Chesapeake Bay, Michael D. Arendt, Jon Lucy, Thomas A. Munroe
Seasonal Occurrence And Site-Utilization Patterns Of Adult Tautog, Tautoga Onitis (Labridae), At Manmade And Natural Structures In Lower Chesapeake Bay, Michael D. Arendt, Jon Lucy, Thomas A. Munroe
VIMS Articles
Ultrasonic transmitters were surgically implanted into adult tautog (n=27,400-514 mm TL) to document seasonal occurrence and site utilization at four sites situated within known tautog habitat near Cape Charles, Virginia, in lower Chesapeake Bay. Tagged tautog were released at the same sites where originally caught within 2 h of capture. Sites were continuously monitored with automated acoustic receivers between 9 November 1998 and 13 October 1999. Two sites consisted of natural bedform. materials and two sites consisted of manmade materials. Ninety-four percent of tautog (n=15) released in fall 1998 remained inshore during winter at sustained water temperatures of 5-8 degreesC, …
Stomach Content Analysis Of Cobia, Rachycentron Canadum, From Lower Chesapeake Bay, Michael D. Arendt, John E. Olney, Jon A. Lucy
Stomach Content Analysis Of Cobia, Rachycentron Canadum, From Lower Chesapeake Bay, Michael D. Arendt, John E. Olney, Jon A. Lucy
VIMS Articles
No abstract provided.