Resistência do mexilhão Perna perna a altas temperaturas e sua relação com a contaminação bacteriológica

Abstract

Brown mussel Perna perna is a common species in Brazilian seacoast, very abundant between Rio de Janeiro and Santa Catarina states. Temperature is one of the most important environmental factors, bounding the species distribution. It has a direct infl uence on basic physiological processes. This study aimed at determining the mussel resilience to high temperatures. The animals were collected from two rocky coasts, the fi rst is located at Urubuqueçaba Island, (Santos – SP), a sheltered site subjected to bacteriological contamination. The other station is Guaraú Beach, (Peruíbe – SP), an open sea site free of contamination. The experiments were conducted in January and July 2001. The temperatures tested were 29.5, 31.0, 32.5 and 34.0ºC, each one with four replications. The time elapsed to occur 50% of mortality (TM 50) and the number of dead animals in each parcel after a defi ned exposition time were recorded. The results showed that mussels from Urubuqueçaba were less resilient to high temperatures than those from Guaraú. This may point out that mussels’ resilience is affected by the high bacteriological contamination even considering different sheltering conditions at both studied sites.