A starvation test to determine optimal salinities for larval freshwater prawns, Macrobrachium rosenbergii

Abstract

1. 1. A starvation test was conducted in small beakers with stage 1 (S1) and stage 2 (S2) Macrobrachium rosenbergii larvae to determine optimal salinities. 2. 2. Experiments were first performed with S2 larvae at 13 ppt to identify a suitable medium made with artificial sea salts. 3. 3. A broad-range (0–35 ppt) and a subsequent narrow-range (9–16 ppt) salinity experiment with S2 larvae were used to identify 13 ppt as the optimal salinity, with 12 ppt as the next best; this agrees well with most previous estimates of optimal salinities for rearing larvae. 4. 4. S1 larvae were also tested in a narrow-range salinity experiment but were not used further because, unlike starved S2 larvae, they molted during the experiment. 5. 5. Identification of the optimal salinity was not affected by 50% daily water exchange or by bright light. 6. 6. Exposure of larvae to three different salinities—7, 13 and 19 ppt—during S1 influenced the width of the optimal salinity range for S2 larvae.