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.

Automated summary

This study examines the cultivation process of striped bass larvae through two trials. The results demonstrate that the daily ration of enriched Artemia and initial stocking density significantly affect the losses and weight gain of the larvae. Additionally, a low ration leads to increased losses due to cannibalism.