Performance and Macronutrient Composition of Age-0 Burbot Fed Four Diet Treatments

As there are few larval-diet rearing methods for burbot Lota lota, it is important to develop these methods for ongoing conservation and future commercial aquaculture efforts. The performance and macronutrient composition of age-0 burbot were compared after fish were fed four different diets for 8 weeks. Diets included three commercial larval-rearing diets and Daphnia magna. Performance metrics involved mean length and weight, survival, and cannibalism. The macronutrient composition (dry matter) of fish and diets was measured as the percentages of moisture, lipid, protein, and ash, along with energy content. Significant differences in mean length and weight occurred, although survival and cannibalism were not different among treatments at the end of the experiment. Mean weight and length were significantly higher with diets 1 and 2. Fish fed diet 2 had the greatest mean survival (32%), followed by those fed the D. magna diet (30%), diet 3 (27%), and diet 1 (25%). Fish fed diet 1 experienced the greatest amount of cannibalism (48%), followed by those fed the D. magna diet (43%), diet 3 (43%), and diet 2 (26%). The macronutrient compositions of whole-body burbot were 81.83-86.91% for moisture, 4.42-20.49% for lipid, 63.53-75.65% for protein, and 8.41-14.25% for ash, and energy content was 4,818-5,915 kcal/g. Diets 1 and 2 provided the best performance among the all diets and may be used in ongoing and future burbot aquaculture efforts. This study demonstrates that burbot can be reared with multiple commercial larval diets and provides the first reported macronutrient compositions and relative cannibalism of age-0 burbot. This study will help advance the ongoing Kootenai Tribal burbot conservation aquaculture program and may have important applications in other conservation and future commercial production efforts.