Effects of mother and postnatal food condition on larval performance of swimming crab Portunus trituberculatus

Abstract

Seed production of the swimming crab Portunus trituberculatus in Japanese hatcheries frequently shows larval mass mortality because of abnormal morphologies and nutritional deficiencies. We conducted two laboratory experiments to explore the optimal food conditions for larval culture in this species. In experiment 1, hatchlings of three mothers were separately reared under different supplementation densities of digestible Nannochloropsis oculata for feeding to the Artemia nauplii provided to larvae. In experiment 2, hatchlings of three other mothers were separately reared under different supply densities of Artemia nauplii that had been cultured with different densities of digestible N. oculata. To evaluate larval performance, we examined larval morphogenesis and measured somatic growth of the carapace, starvation tolerance, development rate, and metamorphosis success. The food conditions significantly affected larval morphogenesis and growth. Additionally, we found large differences in many larval traits among the larvae hatched from different mothers. The food condition for achieving better survival differed among broods; thus, the optimal food conditions varied for larvae of different mothers. We conclude that seed-production success or failure depends largely on a match or mismatch between larval culture methods and characteristics conferred by the mothers used.