Effects of copper on the metabolism of three species of tropical oysters, Saccostrea cucullata, Crassostrea lugubris and C-belcheri

The rapid industrial development in Southeast Asia, in combination with increased population pressure, has in many places caused degradation of natural resources that many people in the region highly depend on. Attempts to evaluate environmental impacts and changes in the ecosystem due to pollution suffer from lack of data, since most knowledge about marine pollution is based on experiences from temperate areas. In the present work, physiological effects of enhanced copper concentrations on three oyster species of commercial interest were studied in laboratory experiments. Two of the species are intertidal, Saccostrea cucullata and Crassostrea lugubris, and one species is subtidal, C belcheri. After a short-term (12 h) exposure to 20 mug copper/l, the oxygen consumption, ammonia excretion, clearance rate and absorption efficiency were measured and scope for growth calculated. The results from this study indicate that the two intertidal species are far more tolerant than the subtidal species. This is probably because they inhabit a more variable environment and have to be able to handle constantly changing environmental conditions. The subtidal habitat is normally less variable, why the copper exposure was a more severe stress, seen mainly as decreased filtration activity. The final result, i.e. changes in scope for growth, indicates that for the specific stress factor studied here, habitat selection seemed to be more important than genus. (C) 2002 Elsevier Science B.V. All rights reserved.