CHEMICAL COMPOSITION OF BLACK ROCKFISH (SEBASTES MELANOPS) FILLETS AND BYPRODUCTS

Black rockfish are important in the near shore fishery of Southeast Alaska, being the only species among the pelagic shelf rockfishes with a directed fishery in State waters. The purpose of this study was to determine the composition of black rockfish fillets, heads and livers. Fillet yields were low at 13.7% of whole fish weight (WFW), while heads and livers composed 24.8 and 1.9% of WFW, respectively. Byproducts were a valuable source of lipids, and the marine oils extracted from these tissues were similar in many aspects to oils from other cold water marine finfish, being rich in omega-3 and low in omega-6 fatty acids. Protein content of fillets, heads and livers were within the expected range (15-20%). Amino acid analysis revealed that byproducts protein fractions were of high nutritional value. Results indicated that these byproducts have value and could be further processed into protein powders, fishmeal and fish oils. PRACTICAL APPLICATIONS This research is part of an ongoing effort to increase the value of Alaska fisheries by promoting entire utilization of the catch. There is opportunity to improve utilization of fisheries' byproducts by converting these materials into fishmeal, fish oils and protein powders that can either be used as ingredients for the manufacturing of feed further purified for food applications.