An efficient method for raising larvae of sakura shrimp Lucensosergia lucens to the post-larva stage

Sakura shrimp Lucensosergia lucens are pelagic shrimp that reside in the North Pacific Ocean. In Japan, commercial fishing activities aimed at this shrimp species only occurs in Suruga Bay in Shizuoka prefecture, but there has been a dramatic decrease in the magnitude of the harvest in recent years. Because sakura shrimp reside in the deep sea, their food habits and feeding behaviors are not well understood. The objective of this study was to establish a method for efficiently raising sakura shrimp larvae to juvenile shrimp. When a newly hatched larva was cultured individually, it developed to the post-larval stage when fed a sufficient amount. However, when ten individuals were cultured together, the survival rate sharply declined after 10 days owing to the cannibalism by elaphocaris III-stage larvae. This cannibalism was not due to the shortage of food because the cannibalism rate significantly dropped when larvae density was decreased to less than 1 individual/mL. The longest lifespan of a larva was 97 days, which is the longest recorded time for a sakura shrimp larval culture. Our results suggested that sakura shrimp larvae can develop to the post-larval stage in a laboratory-scale culture if the expression of cannibalism is inhibited by decreasing the larva density.