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This experiment was designed to determine if there were differences (biochemical and/or organoleptic) before and after canning rested and stressed skipjack tuna. The live fish were captured off Oahu and were placed in shoreside tanks in Honolulu, Hawaii. After having been under observation for 24 hr, the fish were sacrificed in a rested or stressed condition. Stress was induced by forcing fish to swim around a tank until they showed signs of exhaustion. The rested fish were kept in a separate tank and were agitated as little as possible before being sacrificed. Some of the sacrificed tuna were canned immediately to serve as controls. Others were held in 32°, 60°, and 78° F seawater (SW) for 6 hr, and some were held in 78° F SW for 9 hr before canning. An equal number of fish from all treatments were brine frozen (for 20 hr), then thawed and canned. Sample wedges were taken before canning for measurements of glycolytic and purine degradation products. These measurements together with organoleptic evaluation were also determined on the canned product. There were no commercially discernible differences between rested and stressed skipjack subjected to various time-temperature treatments. The relation of the measured biochemical parameters to the treatment of the fish and the subsequent relation to the quality of the canned product were studied. There were not sufficiently defined relations on which to base quality predictions.
Results of the second year of operation of the NMFS/MARAD Ship of Opportunity Program are presented in the form of vertical distributions of temperature and horizontal distributions of sea surface salinity and temperature. Operational and data management procedures also are discussed.
A total of 20, 532 pink salmon (Oncorhynchus gorbuscha) were tagged and released in southeastern Alaska north of Sumner Strait during the years of 1938 to 1942 inclusive, and in 1945. The recovery of 7, 027 of these tags in the fish traps confirmed the findings of other investigators that the pink salmon stocks of the northern part of southeast Alaska are separate from those in the southern part. They also show that pink salmon enter the northern part of southeast Alaska through two paths: (1) through Icy Strait, and (2) through the lower end of Chatham Strait. No evidence was found of movement through Peril Strait from Salisbury Sound into Chatham Strait. The centers of density of each group of tags appeared to move in a consistent manner, but a smaller number of tags from each release were dispersed throughout the northern part of southeastern Alaska. Differences were noted between the movements of fish in odd and even years. Also a larger proportion of earlier tagged fish moved to recovery locations father [sic] inland. In all areas and in all years the fishing season closed about the time of the greatest abundance of fish in the fishery, therefore the later parts of the runs were not studied. Apparently the 1941 run was the largest and that in 1945 the smallest. Migration rates were studied by plotting the catch per trap as well as by the recovery of tags. The latter showed movements of 9.05 to 33.37 miles per day. Survival rates computed for thirty releases with total tag recovery periods of two or more weeks averaged 0.384. Weekly exploitation rates varied from 0.142 to 0.452 averaging 0.250. The weekly F exponential rate of fishing averaged 0.514. Recoveries of tags from seines were not used since their proportion of tags recovered was less than one-half their proportion of the catch. Recommendations are made for future tagging experiments based upon the results of this analysis.