V S Kakati

Optimal salinity and temperature for early developmental stages of Penaeus merguiensis De man

The combined effects of temperature and salinity on the hatching success, survival and development of the larval stages of Penaeus merguiensis were investigated in a 4×2 factorial designed experiment employing two temperatures (29±1 and 33±0.5 °C) and four salinities (25, 30, 35 and 40 ppt). Best percentage of hatch was obtained at 33 °C and 35 ppt (87%) followed by 29 °C and 35 ppt (82%). Similarly during naupliar stages, high survival rate was obtained at 33 °C and 35 ppt (89%). Metamorphosis cycle during the protozoeal stages (protozoea 1 to postlarva 1) was extended and survival rate decreased at 25 ppt. Development to PL1 was faster at 33 °C (7–8 days) as compared to 29 °C (8–10 days) regardless of the salinity levels. Maximum survival during the protozoeal stages was at 35 ppt followed by 48% at 33 °C and 45% at 29 °C. Results showed that salinity exerted a greater influence than temperature on the survival and development of larvae. Based on the results, the best temperature–salinity combination for larval survival and metamorphosis of P. merguiensis is 33 °C and 35 ppt. A salinity range of 30–35 ppt is ideal for larval development.