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1989

Marine Biology

Mercenaria

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Full-Text Articles in Life Sciences

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 …


Effects Of Intensive Fishing Effort On The Population Structure Of Quahogs, Mercenaria Mercenaria (Linnaeus, 1758), In Narragansett Bay, Michael Rice, Charles Hickox, Itrat Zehra Dec 1988

Effects Of Intensive Fishing Effort On The Population Structure Of Quahogs, Mercenaria Mercenaria (Linnaeus, 1758), In Narragansett Bay, Michael Rice, Charles Hickox, Itrat Zehra

Michael A Rice

Mercenaria mercenaria and sediment samples were collected from 3 locations in Narragansett Bay: Greenwich Cove, Greenwich Bay, and the West Passage. Greenwich Cove has been closed to shellfishing for several decades. Average density of quahogs in the cove was 190/m super(2), ranging from 32 m super(2)-500/m super(2) in 30 quadrats. Average valve length of quahogs in Greenwich Cove was 62 mm. Average density in Greenwich Bay was 78/m super(2), ranging from 8/m super(2)-184/m super(2). Average valve length was 31 mm. There was a slightly higher content of very fine-grained sands, silts, and clays in the Greenwich Cove sediments. Average Mercenaria) …