OPTIMUM ACCLIMATION TEMPERATURE, THERMAL PREFERENDUM AND THERMAL TOLERANCE OF SEA CUCUMBER Isostichopus sp. aff badionotus.
We studied the optimum acclimation temperature, the thermal preferendum and thermal tolerance of sea cucumber Isostichopus sp. aff badionotus, with the aim to knowing its thermal requirements and to contribute to the development in its culture technology. For the determination of the optimum temperature of maintenance, 30 sea cucumbers were exposed to 23°C while 30 others were exposed to 26°C for a period of 30 days (10 animals/tank; 3 replicate per each temperature). Mortality and the specific growth rate (SGR), were evaluated. To evaluate thermal preference 12 sea cucumbers were acclimatized to 23°C and 12 more to 26°C. Specimens (4 individuals each time) were exposed in a thermal gradient (20 to 29°C) and behavior was monitoring during 4 hours. The thermal preferendum was established too. The thermal tolerance was determined through the critical thermal maximum (CTM) and the critical thermal lower (CTL) methods. In the optimum acclimation temperature trials no statistically significant differences were found in average weight (P> 0.05); the highest survival (86%) was evidenced in the temperature of 23ºC and therefore this was considered as the optimum temperature of maintenance. The thermal preferendum suggested the interval between 23 and 26ºC as the thermal preference of animals acclimated to 23 and 26°C. Finally the CTM was established in 36.5 ± 0.3°C and the CTL in 8 ± 0.5°C. In Isostichopus sp. aff badionotus, the acclimation temperature influences on their thermal preference.