Burbot (Lota lota maculosa ) are one of the most promising new species for commercialization as a foodfish. However, burbot larval culture relies solely on the use of live prey items , such as rotifers and Artemia for food. Production of live feed is expensive, labor intensive, and often requires substantial space allocation for an aquaculture facility. For th ese reasons, a study was conducted to determine the potential use of frozen copepods and an otohime commercial diet as a substitute for live feeds in burbot larval culture.
An eight-week feeding trial (8-64days post hatch [dph]) was conducted to evaluate the effect of weaning diet on burbot larval growth and survival. A total of 7200 b urbot larvae were distributed into six feeding regimes (FR): FR-A (control) , FR-B, FR-C , FR- D, FR- E and FR- F (Table 1), each with three replicates . At the end of the trial, results showed that survival and growth in treatment E and F (fed copepods) were significantly reduced compared to other treatments (Figures 1 and 2 ).
Early use of Otohime diet and copepods in treatments C, E and F demonstrated that larvae could be fully weaned from live food by 35 dph, 32 dph, or 30 dph, respectively. This reduced the length of time live prey items was required by 14 days, 17 days, and 19 days, respectively when compared to our standard control regime where larvae are weaned by 50 dph . Thus, the results of this study demonstrate the potential to utilize frozen copepods and O tohime dry diet as substitutes for live food in burbot larval culture; however, further optimiz ation is required to improve survival for such feeding regimes and evaluate potential long-term nutritional benefit from feeding copepods in comparison to control regimes.