地理ジャーナルと自然災害
オープンアクセス

概要

Survival Rate and Development Period of the Larvae of Portunus pelagicus (Decapoda, Brachyura, Portunidae) In Relation to Temperature and Salinity

R Ravi, MK Manisseri

Berried females of Portunus pelagicus (Blue swimmer crab) were collected from the wild and the zoea 1 obtained from a single berry were stocked in 200 litre tanks at the rate of 25 numbers/mL. In order to study the independent effects of temperature and salinity, the larvae were reared in three different temperatures (26°C, 28°C and 30°C) at a fixed salinity of 35 ppt and in three different salinities (25 ppt, 30 ppt and 35 ppt) at a fixed temperature of 28°C. Feeding was carried out with microalgae, rotifers, moina and formulated shrimp feed, which varied with stage. The survival rates at each stage in all the trials were assessed by random sampling. The most ideal temperature and salinity among those studied were calculated in relation to the overall survival rate and larval development period. The data pertaining to both temperature and salinity manipulated investigations were found to be significant (P < 0.01) when subjected to one-way ANOVA. Among the tested temperatures, the highest average survival (14.12 ? 0.31%) and the lowest average development period (14.67 days) were obtained at 30 ± 0.1°C. Among the salinity values tested, the highest mean survival rate (06.89 ± 0.06%) and the lowest average development period (14.33 days) were obtained at 35 ppt.