Optimizing early weaning protocols for burbot (Lota lota maculosa) larvae

Abstract Burbot ( Lota lota maculosa ) hold enormous potential for freshwater commercial aquaculture. Current larval burbot rearing involves providing live prey for initial feeding. Two trials were conducted to investigate the reduction of live prey for larval burbot. In Trial 1, five treatments were evaluated: the control group (C) received rotifers ( Brachionus plicatilis ) and Artemia spp. from 11‐50 days post‐hatch (DPH). Treatment one (Trt 1) had live feeds from 11‐78 DPH, treatment two (Trt 2) received only microparticulate diets, treatment three (Trt 3) fed rotifers at 11‐22 DPH and Gemma microparticulate diets at 21‐50 DPH, while treatment four (Trt 4) had rotifers at 11‐20 DPH, then co‐feeding of Artemia spp. and EZ Artemia (liquid Artemia replacement) at 21‐32 DPH, followed by EZ Artemia at 33‐40 DPH. Trial 1 revealed that providing EZ Artemia reduced the live feeding period by 17 days, but survival and growth were significantly lower compared to the control. In Trial 2, five feeding treatments were assessed: the control group (C) was the same as in Trial 1. Treatment one (Trt 1) received rotifers at 11‐25 DPH and EZ Artemia at 20‐50 DPH; treatment two (Trt 2) had Artemia spp. from 11‐30 DPH and EZ Artemia at 25‐50 DPH; treatment three (Trt 3) received only EZ Artemia ; treatment four (Trt 4) had Artemia spp. at 11‐21 DPH followed by co‐feeding of Artemia spp. and Gemma Wean at 22‐32 DPH, and exclusive feeding of Gemma Wean from 33‐78 DPH. Survival rates ranged from 0% to 30.94%, with Trt 1, Trt 2, and Trt 4 reducing the live feeding period by 17‐24 days. Survival for Trt 1 and Trt 2 groups did not significantly differ from the control. Overall, these studies demonstrate that eliminating rotifers or Artemia during burbot larviculture can be achieved with minimal adverse effects on survival and growth.