Juvenile Bay Scallops Research Articles

Chlamydiosis: a newly reported serious disease of larval and postmetamorphic bay scallops, Argopecten irradians (Lamarck)

Abstract. Diseases of bivalve molluscs characterized by the presence of prokaryotic intra‐cytoplasmic inclusion bodies in epithelial cells are reviewed. The paper reports the history, clinical and pathological findings during hatchery epizootics of chlamydiosis in larval and postmetamorphic bay scallops, Argopecten irradians (Lamarck), and enzootic infection in wild, captive and cultured adult and juvenile bay scallops during a 15‐year period (1972–1987) of surveillance for scallop diseases in the northeastern Atlantic coastal region of the United States. The disease was found in 44·4% of adult bay scallop laboratory accessions as an endemic disease without overt clinical signs or mortalities, and as a highly fatal epizootic disease with a rapid course in 20% of hatchery‐reared larval and postmetamorphic bay scallop accessions. The pathogenesis and development of the chlamydial agent during hatchery epizootics are described. The importance of the congenital ‘childhood’ diseases of larval bay scallops and other species of bivalve molluscs is discussed.

Copper toxicity to the bay scallop (Argopecten irradians).

Coastal marine environments are commonly used for disposal of industrial waste, dredge spoils and sewage sludge, which contain high concentrations of copper and other heavy metals. For example, in the New York Bight, a daily input of copper at 14 tons is estimated. This input has resulted in concentrations up to 390 mg kg/sup -1/ (dry) Cu in the sediment and concentrations as high as 20 ..mu..g L/sup -1/ in the seawater. Adverse effects of copper on some species of marine life have been well documented. However, most toxicity data available for bivalves are from static acute toxicity tests, even though long-term flowing water bioassays provide more realistic exposure conditions. To date, no studies have been conducted on copper toxicity to the bay scallop, Argopecten irradians, a commercially important species. The purpose of this study was to examine the effect of copper on survival, growth, and byssal attachment, and copper accumulation of juvenile bay scallops in a flowing water exposure system.

Mercury stress on juvenile bay scallops, Argopecten irradians, under various salinity-temperature regimes

Survival of juvenile bay scallops, Argopecten irradians, after 96 h of exposure to mercury at various salinity and temperature regimes was studied. Scallop survival was significantly affected by mercury concentration and by salinity, as well as by the interaction between temperature and concentration and between temperature and salinity. Toxicity of mercury at low concentrations was enhanced by high temperature and low salinity, whereas at high mercury concentrations this effect diminished.

Biological effects of heavy metals on Juvenile Bay scallops,Argopecten irradians, in short-term exposures

It is apparent that increases in human population and technological development are causing serious stress on the inshore marine environment, with a resulting decrease in its effective use. Bivalve molluscs are one of the most important commercial fisheries in shallow waters of bays and estuaries and many areas used for cultivation of these shellfish are frequently subjected to both industrial and domestic pollutants. Such pollution, both man-made and natural, fosters conditions that may diminish the harvest of marine resources. For example, Connecticut landings of the bay scallop,Argopecten irradians, amounted to 50,160 pounds in 1898 (Townsend, 1900), but dropped to 36,200 pounds in 1939 (Fiedler, 1942), and disappeared in 1969 (Wheeland, 1972). A possible cause for the decline may be environmental perturbations.