The Roles of Environmental Stressors and Culture Methods on the Summer Mortality of the Pacific Oyster Crassostrea gigas [Abstracts of Presentations.]
Cheney D, Elston R, MacDonald B, Kinnan K, Suhrbier A. 2001. The Roles of Environmental Stressors and Culture Methods on the Summer Mortality of the Pacific Oyster Crassostrea gigas [Abstracts of Presentations.]. Journal of Shellfish Research. 20(3):1195
During the late summer to early fall period, Pacific oysters cultured on the west coast of the United States and elsewhere may experience high levels of mortality. In the 1960's to 80's, this condition was subject to intensive investigation focusing on broad areas of disease pathology, genetics, physiology and the environment. Results of these studies were largely inconclusive, or pointed to a poorly defined etiology. Although several factors, such as a bacterial and herpes-like virus infections could be linked to certain mortality events, no clear picture emerged. Recent studies in Puget Sound, Washington USA and Tomales Bay, California USA center on the influence of multiple stressors and their affects on oyster survival, physiology and pathology. The goal of this research is to identify possible modifications in culture practices, brood stock selection or grow-out location to increase survival of Pacific oysters. Field observations indicate oysters are subject to extreme variations in a number of parameters during intertidal cycles. Annual or seasonal variations in those parameters and culture practices appear to play a major role in oyster survival. An increased rate of oyster mortality and modified physiological response appears to be strongly correlated with both elevated temperatures and extended periods of depressed DO. A long period of neap tides with low and slack water during the evening was observed to result in daily and successive reductions in DO to levels ranging from 0.5 and 2 mg/L. The DO reductions are sometimes coupled with heavy macroalgae blooms and high phytoplankton densities. This and other work indicate oyster summer mortality rates are also strongly influenced by ploidy and broodstock origin/stock selection. These observations have renewed interest in testing selected stocks with reduced rates of summer mortality, which still retaining desirable characteristics of good growth and meat yield.
- Type
- Journal Article
- Authors
- Cheney, D; Elston, R; MacDonald, B; Kinnan, K; Suhrbier, A
- Units
- PORE
- Keywords
- Aquaculture, Aquaculture techniques, biological stress, brood stock selection, Cultured organisms, grow-out location, Marine molluscs, Mortality causes, multiple stressors, oyster culture, Oysters, Pacific giant oyster, Physical Science, Ploidy, shellfish culture, Site Selection