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Habitat Requirements For The Softshell Clam, Mya Arenaria In The Chesapeake Bay, Patrick Baker, Roger L. Mann

Reports

Large populations of softshell clams persist only in relatively shallow, sandy. mesohaline portions of Chesapeake Bay. These areas are mostly in Maryland, but can also occur in the Rappahannock River. Virginia. In some other portions of the bay, especially polyhaline portions. sparse populations of soft shell clams persist subtidally. Restricted populations exist intertidally.

Softshell clams grow rapidly in Chesapeake Bay, reaching commercial size in two years or less. They reproduce twice per year, in spring and fall, but probably only fall spawnings are important in maintaining population levels. Major recruitment events do not occur in most years. despite heavy annual …

Juvenile Finfish And Blue Crab Stock Assessment Program Bottom Trawl Survey Annual Report Series Volume 1989, Patrick J. Geer, Christopher F. Bonzek, James Colcovoresses, Robert Harris Jr.

Reports

This report summarizes data collected by the Virginia· Institute of Marine Science (VIMS) trawl survey monthly cruises for January through December, 1989. The trawl survey is a long term, broad scope monitoring program. Its primary goal is to produce annual indices of juvenile (young-of-year) abundance of commercially, recreationally and ecologically important marine and estuarine finfish and crustaceans. The objective is to provide indices of sufficient accuracy and precision for both immediate resource management needs and long-term understanding of environmental influences on fishery resources. A second important product of this effort is the documentation and monitoring of habitat utilization by juveniles …

Habitat Requirements For The Hard Clam, Mercenaria Mercenaria, In Chesapeake Bay, G.Curtis Roegner, Roger L. Mann

Reports

The hard clam, Mercenaria mercenaria, is found along the eastern coast of North America from the Gulf of St. Lawrence to Texas. In Chesapeake Bay the hard clam is restricted to salinities above approximately 12 ppt. The abundances and distribution patterns of hard clams in Chesapeake Bay are based on studies performed nearly 20 years ago - a more extensive survey of hard clam resources is due. Statements concerning long term trends in populations are not feasible.

The basic anatomy of hard clams conform to that of venerid bivalves. Hard clams grow to a maximum shell length (anterior-posterior dimension) of …