Effects of Salinity on Survival, Feeding, and Development of Larvae of the Red Frog Crab Ranina ranina

Abstract

Salinity effects on the survival, intermolt period, growth, and morphogenesis of Ranina ranina larvae were examined under 11 levels ranging from 17 to 51%, S. Zoeas metamorphosed into megalopas at 24 to 37%, S. The optimum range of salinity for survival became narrower in later instars. Intermolt periods were prolonged at lower and higher salinities. The metamorphosis rate increased with increasing salinities. Morphogenesis proceeded without change in all salinity levels until instar V but was delayed at 20,24, and 41 % S from instar VII. Larval food consumption was examined under 5 salinity levels from 20 to 48%o S with zoeas at instars I, III, V, and VII. It was the highest at 34% S and decreased at the other salinities. The retarded growth was correlated with decreased food consumption at lower and higher salinities in instars III, V, and VII. The optimum range of salinity for rearing larvae of this species was 27-34% S. Food energy seemed to be utilized for survival first, molting second, morphogenesis and growth last. © 1992, The Japanese Society of Fisheries Science. All rights reserved.