Accession Number : ADA180387

Title :   Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (North Atlantic). HARD CLAM,

Corporate Author : MAINE COOPERATIVE FISHERY RESEARCH UNIT ORONO

Personal Author(s) : Stanley,Jon G. ; DeWitt,Rachael

Report Date : OCT 1983

Pagination or Media Count : 29

Abstract : Species profiles are literature summaries on the taxonomy, morphology, range, life history, and environmental requirements of coastal aquatic species. They are designed to assist in environmental impact assessment. The hard clam, Mercenaria mercenaria, is the most extensively distributed commercial clam in the United States, but at the northern end of its range in the North Atlantic region it has large fluctuations in population. Spawning occurs in summer at 18 to 30 C. Eggs and larvae are carried by currents in estuaries for 6 to 12 days, and then seed clams set on sand or pebbles. Seed clams that lack cover of shells or stone largely perish because of predation. Adults filter feed on phytoplankton. Adults survive temperature of 17 to 30 C and salinities of 10 to 35 ppt, but can withstand freshwater for several days by closing the shell. When the shell is closed they must tolerate anoxic conditions, and they survive less than 1 mg/1 oxygen in the water for several days. Even the larvae tolerate 0.5 mg/1 of oxygen. Growth(Physiology).

Descriptors :   *CLAMS, *FISHES, *MARINE BIOLOGY, ADULTS, ANOXIA, COASTAL REGIONS, COMMERCIAL EQUIPMENT, DISTRIBUTION, DOCUMENTS, EGGS, ENVIRONMENTAL IMPACT, ENVIRONMENTS, ESTUARIES, FEEDING, FILTERS, FRESH WATER, GRAVEL, HISTORY, INVERTEBRATES, LARVAE, LIFE(BIOLOGY), NORTH ATLANTIC OCEAN, OXYGEN, POPULATION, PROFILES, REQUIREMENTS, SAND, SUMMER, TAXONOMY, UNITED STATES, VARIATIONS, WATER, LIFE CYCLES, REPRODUCTION(PHYSIOLOGY)

Subject Categories : Biology
      Biological Oceanography

Distribution Statement : APPROVED FOR PUBLIC RELEASE