EFEITO COMBINADO DE TEMPERATURA E SALINIDADE NA SOBRE VIVÊNCIA DE <em>Sphaeroma walkeri</em> STEBBING, 1905 (CRUSTACEA - ISOPODA)

Abstract

The tolerance of Sphaeroma walkeri to combined effect of salinity and temperature was studied through laboratory experiments. Thirteen salinities, from 0 to 60° /00 and eight temperatures, ranging from 05 to 40° C were employed during 440 hours. Tolerance was expressed through the average time of survival and the estimates of the best conditions were obtainded through the fitted response surface method and bi-dimensional contours. It was observed that Sphaeroma walkeri is tolerant to large intervais of salinity and temperature, there being best conditions for survival respectively between 25 and 40° /00 and 15 and 25°C. At 30° /00 - 20° C, the survival was 100%. An interaction between the effects of salinity and temperature was also observed and the intervals corresponding to largest survivals, for each factor, varied in function of the other.