Abstract
Burbot (Lota lota) are an emerging species for cool or coldwater commercial aquaculture, they grow well under conditions used for trout and other salmonid culture, are refractory to many salmonid pathogens, and are highly regarded for their fillets, roe, liver, and skin (for leather products). The complete life cycle of burbot is understood and can be conducted in captivity, however, methods for commercial burbot culture have not been fully developed. The overall goal of this thesis is to investigate reproductive, dietary, and immunological parameters of this species to maximize their production potential, which will facilitate growth and producer interest in burbot as a commercial aquaculture species. This dissertation further evaluates soy replacement of fishmeal in burbot diets to provide a baseline for formulating more environmentally sustainable diets for this species. Determining the gastric evacuation rate and digestibility of diets containing relatively high inclusions of soy products will keep costs low while ensuring dietary quality. Results from this work confirm that grow-out stage burbot can tolerate inclusions of soybean meal and soy protein concentrate, replacing 25% of fishmeal in a traditional trout diet formulation, without adversely affecting growth, gastric evacuation rate, or digestibility of certain macronutrients. Induction of sterility in burbot may be necessary to allow burbot to be cultured in areas where escapement is a risk. Research, detailed herein, demonstrated methods for producing triploid burbot, and that these triploids are sterile. Methods to consistently generate triploids, and some tetraploid fish, were optimized and 100% induction could be achieved through various pressure shock protocols. Control of spawning occurrence independent of season is another important consideration for a new species and allows producers to mitigate the risks inherent in a single annual spawning season as well as generate multiple cohorts of burbot annually. Using photothermal manipulation, it was demonstrated that out of season spawning of burbot can be achieved. Finally, there is a need to develop tools for future health management of burbot. One such tool is a monoclonal antibody capable of detecting species specific IgM. This was achieved and an enzyme linked immunosorbent assay (ELISA) developed to characterize the antibody response of burbot previously exposed to pathogenic strains of Aeromonas sp.