Salinity effects on the larval development of Pagurus bernhardus(l.) reared in the laboratory

The larvae from two Pagurus bernhardus females were reared in the Marine Biological Laboratory, Heisinger, Denmark, in two series at 10° C. and in five salinities from the time of hatching until death occurred or until the hermit stage was reached. In a range of salinities from 15‰ to 3S‰ there was an increase in mortality with a decrease in salinity. Additional causes of mortality included cannibalism of zoeae, particularly in the higher salinities, and failure of glaucothoe to enter a small snail shell. A salinity of 15‰ was too low for first stage zoeae to molt to the second zoeal stage, but some lived for over four weeks. In salinities of 20‰ some zoeae molted twice but at a slower rate than those in higher salinities. Larvae maintained at 25‰, 30‰ and 35‰ molted at a remarkably uniform rate in both series. Zoeal development was completed in 39 to 47 days and development from the time of hatching to the hermit stage took from 52 to 70 days with the majority completing metamorphosis in 60 days. Comparison of the development of larvae from two females shows some differences in their survival and tolerances to a range of salinities.