Summer Mortality and the Stress Response of the Pacific Oyster, Crassostrea gigas Thunberg
Friedman CS, Shamseldin A, Pillai M, Olin PG, Cherr GN, Jackson SA, Rifkin E, Uhlinger KR, Clegg JS. 1997. Summer Mortality and the Stress Response of the Pacific Oyster, Crassostrea gigas Thunberg. Journal of Shellfish Research. 16(1):335
Summer mortalities of Crassostrea gigas in Tomales Bay, California have approached 52% in 1993 and 63% in 1994. It is likely that multiple chronic stresses may combine to bring about mortalities. In order to examine possible etiologies of C. gigas losses in Tomales Bay, we monitored several environmental parameters in conjunction with a sentinel study in which seed from two sources were planted at 3 farms in the bay. Mortality was observed in late July and August of 1995 and was associated with water temperatures above 20 degree C and a bloom of Gymnodinium splendens. Microscopic examination of stained tissue sections during a mortality episode revealed a diffuse to acute and multi-focal inflammation surrounding digestive tubules, thickening of peritubular muscularis and connective tissue, and increased vacuolization and dilation of digestive tubules. These data suggest that mortalities are related to environmental causes and not an infectious agent. Thermotolerance was induces in Pacific oysters by heat shock (HS) which enable them to withstand an otherwise lethal temperature. Thermotolerance was maintained for up to two weeks following HS and was accompanied by the appearance of an inducible isoform of the stress protein-(SP)-70 family via synthesis. This induced SP has a molecular weight of 69 kDa and is observed in gill, mantle, and heart tissues and may be a useful biomarker for stress in Pacific oysters.
- Type
- Journal Article
- Authors
- Friedman, C; Shamseldin, A; Pillai, M; Olin, P; Cherr, G; Jackson, S; Rifkin, E; Uhlinger, K; Clegg, J
- Units
- PORE
- Keywords
- biological stress, California, Crassostrea gigas, Environmental Effects, ER: Environmental Regime Marine, INE, Mortality, shellfish culture, Tomales Bay, USA