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VIMS Articles

Predation

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Full-Text Articles in Life Sciences

Do Striped Bass And Blue Crab Abundances Correlate In Chesapeake Bay?, Thomas C. Mosca Iii, Paul J. Rudershausen, Rom Lipcius Jan 1995

Do Striped Bass And Blue Crab Abundances Correlate In Chesapeake Bay?, Thomas C. Mosca Iii, Paul J. Rudershausen, Rom Lipcius

VIMS Articles

We examined a corollary to the hypothesis that striped bass regulate the blue crab population in Chesapeake Bay by preying on juveniles, an expected inverse correlation between striped bass and blue crab abundance. Abundance indices based on Virginia striped bass young-of-the-year beach seine data (1980-1992) were constructed for fish ages 1 - 8, and for the Virginia resident stock component, ages 1 - 5. Fishery-independent, pound net data for fall and spring were also used to construct indices of striped bass abundance in Rappahannock River (1986-1993). Juvenile blue crab abundance indices were constructed based on trawl survey data from the James, York ...


Biological Control Of Crab Predation On Hard Clams Mercenaria Mercenaria (Linnaeus, 1758) By The Toadfish Opsanus Tau (Linnaeus) In Tray Cultures, Robert Bisker, Michael Castagna Jan 1989

Biological Control Of Crab Predation On Hard Clams Mercenaria Mercenaria (Linnaeus, 1758) By The Toadfish Opsanus Tau (Linnaeus) In Tray Cultures, Robert Bisker, Michael Castagna

VIMS Articles

Oyster toadfish Opsanus tau (Linne) were tested as biological controls of crab predation on juvenile hard clams Mercenaria mercenaria (Linne) in trays with crushed stone aggregate. Clam survival after 34 weeks was 69.5% in the presence of toadfish and 2.3% in trays without toadfish. Toadfish reduced the total number of crabs (mud crabs and blue crabs). Crabs in trays with toadfish present had smaller carapace widths.


Predation By The Oyster Toadfish Opsanus Tau (Linnaeus) On Blue Crabs And Mud Crabs, Predators Of The Hard Clam Mercenaria Mercenaria (Linnaeus, 1758), Robert Bisker, Mary Gibbons, Michael Castagna Jan 1989

Predation By The Oyster Toadfish Opsanus Tau (Linnaeus) On Blue Crabs And Mud Crabs, Predators Of The Hard Clam Mercenaria Mercenaria (Linnaeus, 1758), Robert Bisker, Mary Gibbons, Michael Castagna

VIMS Articles

The oyster toadfish, Opsanus tau (Linne), reduces predation by xanthid and portunid crabs on juvenile hard clams, Mercenaria mercenaria (Linne), in field cultures. This study examined the influence of size and species on the predator-prey relationship between toadfish and crabs. The mud crabs Eurypanopeus depressus (Smith), Neopanope sayi (Smith), and Panopeus herbstii Milne Edwards of 5-40 mm carapace width and blue crabs Callinectes sapidus Rathbun of 77-105 mm carapace width were offered to toadfish of 70-322 mm total length. Toadfish predation rates on mud crabs were higher with increasing toadfish size and lower with increasing crab size. Toadfish injured or ...


Predation On Single Spat Oysters Crassostrea Virginica (Gmelin) By Blue Crabs Callinectes Sapidus Rathbun And Mud Crabs Panopeus Herbstii Milne-Edwards, Robert Bisker, Michael Castagna Jan 1987

Predation On Single Spat Oysters Crassostrea Virginica (Gmelin) By Blue Crabs Callinectes Sapidus Rathbun And Mud Crabs Panopeus Herbstii Milne-Edwards, Robert Bisker, Michael Castagna

VIMS Articles

Single spat oysters Crassostrea virginica of four size classes (3.4-24.6 mm mean shell heights [SH]) were offered to six size classes of blue crabs Ca/linectes sapidus (9.3-85.5 mm mean carapace width [CW]) and five size classes of mud crabs Panopeus herbstii (7.1-34.4 mm mean CW) for 48 hr. Predation rate, recorded as the number of dead oyster spat/crab/day, was directly proportional to crab size and inversely proportional to oyster size. Mud crabs of 34.4 mm CW and blue crabs of 85 .5 mm CW had predation rates of 22.5 ...


Variable Functional Responses Of A Marine Predator In Dissimilar Homogeneous Microhabitats, Romauld Lipcius, Anson Hines Dec 1986

Variable Functional Responses Of A Marine Predator In Dissimilar Homogeneous Microhabitats, Romauld Lipcius, Anson Hines

VIMS Articles

Adult soft-shelled clams (Mya arenaria) persist at low densities in Chesapeake Bay sandy habitats despite Intense predation by blue crabs (Callinectes sapidus). Clam persistence may be a consequence of variation in blue crab foraging rates as a function of clam density and sediment composition. In laboratory aquaria, we measured the functional responses (prey consumption per predator as a function of prey density) of large blue crabs to six densities of adult soft-shelled clams buried at natural depths in two sediment types (mud and sand). Functional responses in sand and mud were differentiated statistically by analyses of(1) residuals and residual ...