No effect of stocking density on the survival or size of late‐stage Delta Smelt larvae reared in a small‐scale culture system

Abstract

Abstract Objective A small‐scale culture system effective in producing larvae of endangered Delta Smelt Hypomesus transpacificus was recently developed to facilitate conservation and research efforts. Methods To optimize its use, we examined the effect of stocking density (300, 500, 700, and 900 fish per 92 L of water) on the length, weight, and survival of late‐stage larvae (41 days posthatch) reared for 40 days in the small‐scale system. Result Stocking density had no effect on larval survival or size. Also, the survival, length, and weight of these fish did not differ from those reared using standard, large‐scale culture practices (2500 fish per 320 L of water). Conclusion Our findings validate the methods used for small‐scale Delta Smelt rearing, help optimize these protocols, and thereby enhance Delta Smelt rearing capabilities needed for research and conservation.