The effects of brine-freezing and plate-freezing at sea upon 2-thiobarbituric acid (TBA) values, concentration of long-chain free fatty acids (FFA), and flavor of Pacific halibut and chinook salmon were determined at intervals during subsequent storage of the glazed, polyethylene covered fish at − 30 C. Evaluations were conducted on both outside and inside muscle.Brine-frozen samples of outside muscle generally had higher TBA values than plate-frozen samples and the differences were most pronounced at intermediate storage times (26–45 weeks).Method of freezing significantly (P ≤ 0.05) affected the concentration of total FFA in Pacific halibut, and the total FFA concentration of both Pacific halibut and chinook salmon significantly increased with length of frozen storage. For both species the concentration of total FFA was significantly greater in outside than in inside muscle.Significant flavor differences between brine- and plate-frozen samples of outside muscle were evident at intermediate storage times for both species. For inside muscle of halibut, the significance of flavor differences generally increased with storage time whereas flavor differences for inside muscle of salmon were consistently nonsignificant.Taste panel results and TBA values indicated that, in comparison to plate-freezing, brine-freezing impaired the quality of outside muscle of Pacific halibut and chinook salmon during the early stages of frozen storage.