Temperaturas letales superiores para el mejillón, Mytilus galloprovincialis (Lamarck, 1819), en la costa de Chile central

The presence of Mytilus galloprovincialis, widely known as the Mediterranean mussel, have been genetically certified from Coliumo Bay to the Magellan Strait, in central and southern Chile, respectively. To correlate the geographic distribution of this species along the Chilean coast with its physiological tolerance to upper temperatures, experiments were carried out with adults and larval stages. Trochophore, umbonate veliger, and pre-metamorphic larvae were submitted to experimental temperatures from 17-33°C, during 24 h to determine the upper temperature limit. Meanwhile, adult experiments were carried with specimens having different previous physiological background: spring-summer acclimation (November-January), and fall-winter acclimation (August-October) and exposed to temperature range of 17-33°C for period of 24, 48, 72 and 96 h, to verify mortality and byssus formation. Results showed that at larvae stages, the 50% of mortality occurred at 27°C, with 100% mortality at 30°C. Adult stages reached the 55% mortality exposed for 48 h at 30°C and 100% mortality in 72 h at the same temperature. The byssus secretion become failing at 27°C and ceased at 30°C.