Reducing cannibalism among larval striped bass Morone saxatilis: Effects of Artemia ration size and stocking density

Two trials on striped bass larvae, both 2 x 2 factorial design and 16 days duration starting at 12 days post-hatch (dph; 3 mg body weight, BW), compared the effect of stocking density (both trials 3 vs. 15 larvae/L; rearing volume 15 L) and daily fixed ration of stage II enriched Artemia (Trial 1: 1000 vs. 250; Trial 2: 250 vs. 50 Artemia per larva per day; Art/l/d) based on initial stocking density. Losses of larvae were categorized as either retrieved mortalities or 'missing' due to cannibalism. In Trial 1, ration (1000 vs. 250 Art/l/d) had a highly significant (p < 0.001) effect on both overall losses (4 vs. 22%) and final mean wet BW (55 vs. 18 mg), whereas stocking density had a minor influence on losses (p = 0.038), and no effect on final BW (p = 0.700). Losses due to cannibalism in Trial 1 were very low ( 3%). In Trial 2, by contrast, cannibal losses were up to 52%, and overall losses up to 80% primarily due to the low ration of 50 Art/l/d. Overall losses in Trial 2 were strongly dependent on ration (p = 0.028), but independent of stocking density (p = 0.426). Some cannibals grew very fast, their final BW 10 fold greater than conspecifics. In a small production trial, larvae stocked at 15/L were offered a daily ration that increased progressively from 250 Art/l/d at 14 dph to 1200 Art/l/d at 29 dph. Survival was 95% due to negligible cannibalism. Overall, the study presents a protocol for the indoor intensive production of striped bass through the larval stage with minimal losses to cannibalism. Superscript/Subscript Available更多