Effect of pH, salinity and Ca 2+, Mg 2+ K + and SO 42+ ions on hatching and viability of Loligo vulgaris embryo

Abstract

1. 1. The effect of salinity, pH, calcium, magnesium, potassium and sulphate ions on egg hatching and embryonic survival of squid embryos was studied. 2. 2. In artificial sea-water, the embryos hatched normally and lived up to 5–6 days without food. In natural sea-water, they lived up to 6–7 days without food. 3. 3. In sea-water with salinity values from 34 to 42%o and at pH values between 7.8 and 8.4, the embryos developed and hatched normally. Beyond this range, embryos were severely damaged, and some died. 4. 4. The physiological concentrations of Ca 2+, K +,Mg 2+ and SO 4 2− ions, at which embryos hatched and developed normally, were: 9–15 mM, 9–15 mM, 46–70 mM and 15–37 mM respectively.