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Abstract

The present research investigated the effects of nursing on blue swimming cablets (Portunus pelagicus Linnaeus, 1758) between Cup and Substrate methods for 35 days on the survival and growth with and without astaxanthin supplementation. Four treatments (Cup + Asta), (only Cup), (Substrate + Asta) and (only Substrate) were replicated three times in plastic tanks (500 L). Growth performance and the water quality parameters were monitored weekly. Results showed that there was no significant difference (P>0.05) between with and without astaxanthin supplementation in terms of survival, weight and carapace width. The survival of crablets decreased linearly over the nursing period and final survival of crablets in the Cup method (63.0%) remained three times higher (P<0.05) than the Substrate method (21.3%). The final average survival ranged from 16.7 to 68.5%. Among the water quality parameters, temperature, pH, Nitrite (NO2) and Nitrate (NO3) had negative linear correlations with survival, while dissolved oxygen (DO) had positive linear correlations. Average survival at 30 ppt salinity was 1.67 time higher than at 29 ppt salinity. In conclusion, to increase crablet survival during nursing, maintaining suitable environmental conditions and using Cup method are suitable for preventing cannibalism.