As the aquaculture industry expands in the United States, investigation of the commercial aquaculture potential of novel species may allow producers to provide unique products for market. Burbot Lota lota, demonstrates potential for commercial production in northwestern states, all life stages of this cool to cold-water species can be cultured in captivity and grow-out culture conditions are shared with rainbow trout Oncorhynchus mykiss. Burbot offers a thick flake white fillet, delicacies such as roe and liver, and its skin can be used as a leather product. Finally, L. lota is refractory to many salmonid pathogens, offering an option to diversify existing trout production operations. The specific objectives for this USDA Agriculture and Food Research Initiative - Education and Workforce Development fellowship project are to: 1) characterize egg survival and incubator microbiomes within recirculating (RAS) and flow through (FT) systems, 2) characterize larval survival, development, and culture tank microbiomes within RAS and FT systems, and 3) investigate the development of immunological organs and proteins associated with adaptive immunity in larval diploid and triploid burbot.
Conventional burbot egg incubation and larval culture practices utilize single pass aquaculture methodology; however, recirculation technologies may be a viable method to improve sustainability and increase viable farming locations. Thus, a set of experiments were conducted to characterize embryonic and larval survival within RAS and FT systems. Six treatments were utilized: 1) flow-through (FT-NILL), 2) flow-through with hydrogen peroxide treatment (FT-H), 3) flow-through with UV treatment (FT-UV), 4) recirculating (RAS-NILL), 5) recirculating with hydrogen peroxide treatment (RAS-H), and 6) recirculating with UV treatment (RAS-UV). Initial experiments served to refine methods and yielded preliminary survival data. Highest embryonic survival was observed in treatments FT-H, FT-UV, and RAS-H, which were all statistically similar (p = 0.05). The highest larval survival was observed in FT-H, FT-UV, and RAS-NILL, which were all statistically similar (p = 0.05). Together, the embryonic and larval survival indicate that RAS may be a viable approach for burbot early life history culture.
Evaluation of adaptive immunity development in diploid and triploid larval burbot is pending, and refined experiments for the FT vs RAS will be conducted in spring of 2025, also including examination of culture system microbiomes. The results from this project will be of interest to commercial cold-water aquaculture producers and agencies utilizing burbot for management applications, as this may serve to improve the water resource use for burbot early life history culture.