Evaluation of an alternative strategy to enhance salmon populations: Cage rearing wild smolts from Conne River, Newfoundland

Five-thousand wild Atlantic salmon (Salmo salar L.) smelts, from Conne Rive r, Newfoundland, were captured during their downstream migration in May 199 5, and transferred to an estuarine aquaculture rearing site at Roti Bay, 23 km away. Survival was monitored throughout the experiment. The greatest mo rtality occurred in July, approximately 6-8 weeks following transfer. Survi val of smelts. to one-sea-winter salmon was 18.5%, over four times higher t han the average survival of wild salmon to Conne River during the past 6 ye ars. Growth was monitored at monthly intervals until November 1995, with ad ditional sampling in the spring and early summer of 1996. Survivors were sp lit into two groups and released directly into the Bay d'Espoir fjord; one group was released 27-28 June 1996, at a site approximately 7 lan from the mouth of Conne River. The second group was retained at Roti Bay and release d 23: July 1996. Lotek radio transmitter tags were used in evaluating the s uccess of the experiment by tracking migration timing and subsequent distri bution of cage-reared salmon throughout the Conne River system. Approximate ly 80% returned to Come River and 20% strayed to other streams. Less than 5 0% of the surviving fish were later accounted for in local Bay d'Espoir riv ers. Results are discussed in relation to the utility of this technique to enhance salmon populations. (C) 1999 International Council for the Explorat ion of the Sea.