Some studies


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Vincent, L. D., M. Alexandersdottir, et al. (1993). "Mortality of coho salmon caught and released using sport tackle in the Little Susitna
River, Alaska." Fisheries Research Amsterdam 15(4): 339-356.

Coho salmon (Oncorhynchus kisutch) were caught with sport gear in the estuary of the Little Susitna River, southcentral Alaska (USA). Fish were double marked and released. All coho salmon observed migrating through a weir above the estuary and a portion caught in a sport fishery below the weir were examined for marks. A second group of coho salmon were caught using similar sport gear above the estuary. These fish were handled and marked identically as the fish captured in the estuary, except that they were held in a holding pen at the weir with an equal number of coho salmon dip netted at the weir. Coho salmon which were caught and released in the estuary suffered a significantly higher rate of mortality (69%) than did either the coho salmon caught and held above the estuary (12%) or those which were dip netted and held at the weir (1%). Factors that could influence rates of hook-induced mortality were measured at the time of hooking. Hook location, hook removal, and bleeding significantly affected the measured mortality rate.


Bendock, T. and M. Alexandersdottir (1993). "Hooking mortality of chinook salmon released in the Kenai River, Alaska." North American Journal of Fisheries Management 13(3): 540-549.
Short-term (5-d) mortality of chinook salmon Oncorhynchus tshawytscha caught and released in the Kenai River was assessed with radio-telemetry. From 1989 to 1991, 446 adult chinook salmon were tagged with radio transmitters in four experiments. Overall hooking mortality averaged 7.6% and ranged from 10.6% in 1989 to 4.1% in 1991. Mortality was highest for small males ( lt 750 mm mid-eye length) compared with large males and all females. Wound location and bleeding were the factors principally associated with mortality. Survival of chinook salmon that were hooked in the gills or were bleeding was significantly reduced; however, the frequency of these injuries was small in all experiments.
Most mortalities occurred within 72 h of release. These results support the use of hook-and -release regulations in similar freshwater chinook salmon fisheries to reduce sportfishing mortality effectively and achieve spawning escapement goals.

Gjernes, T., A. R. Kronlund, et al. (1993). "Mortality of chinook and coho salmon in their first year of ocean life following catch and release by anglers." North American Journal of Fisheries Management 13(3): 524-539.

The mortality of chinook salmon Oncorhynchus tshawytscha and coho salmon O. kisutch in their first year of ocean life following catch and release by anglers was examined. Five factors were recorded for each landed fish: species, hook type, barb type, injury location, and mortality. For the first time, a recursive causal model was used to analyze hooking mortality data. The data suggest that hooking mortality isbetter described by a two -stage process than by traditional logistic models.
Injury location is affected by hook type and barb type in the first stage, and mortality is affected by injury location and species in the second stage. Overall estimated mortality following release from sportfishing gear was approximately 30% for chinook salmon and 14% for coho salmon.