Impacts of Sublethal and Lethal High Temperatures on Clams Exploited in European Fisheries

Abstract

ABSTRACT In Galicia, three venerid bivalves are exploited in the intertidal zone by local fishery guilds: Venerupis corrugata, Ruditapes philippinarum, and Ruditapes decussatus. The precise effects of the duration and intensity of high-temperature episodes on these bivalves remain largely unknown, especially when the animals are in sediment which acts as a thermal buffer. Clams in sediment were exposed to recorded summer sediment temperatures: 21°C(control), 27°C, 32°C, and 36°C(measured at 2 cmdepth in the sediment) on the diurnal low tide during three consecutive days. Burrowing activity of R. decussatus relative to temperature was a negative quadratic response, typical of performance curves where the upper limit to activity has been exceeded. The venerid bivalve V. corrugata showed evidence of sublethal stress with reduction in burrowing activity, starting at 27°C. Temperatures greater than 32°C are common on days with hot low tides on clam fisheries grounds in Galicia and are expected to increase in f...