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COSEWIC assessment and status report on the Sockeye Salmon Oncorhynchus nerka Sakinaw population in Canada

Supplementation and Restoration

Supplementation by Artificial Propagation

Recent “enhancement” projects for Sakinaw Lake sockeye started in 1986 when 28 000 eggs from Haskins Beach were reared at the Ruby Creek hatchery with the eggs from each female occupying a single tray in the hatchery. Since 1986, all parental fish (brood stock) have been sampled for disease, namely infectious hematopoietic necrosis virus (IHN) and bacterial kidney disease (BKD). All fish were found to be free of either disease, except for one female in 1986, whose eggs were infected with IHN. The 2200 infected eggs were planted back on the spawning beach for natural incubation. The remaining eggs were incubated in the hatchery resulting in 23 000 unfed fry being released into Sakinaw Lake in mid-April 1987. In November 1987, 18 spawning female sockeye were captured (50% from each of Beaches 1 and 2) and their eggs were incubated at the Thornborough Channel Salmon Enhancement Society hatchery on Ouellette Creek. In mid-April 1988, 57 000 unfed fry were released at Beach 1. In 1988, eggs from 18 females were incubated at the Ouellette hatchery producing 33 000 fry that were again released into the lake at Beach 1. Artificial propagation was discontinued until 2000 when 16 000 eggs from 10 females were incubated and the fry reared to 1 g in weight at the Ouellette hatchery; 14 981 “fed fry” were released into the middle of the lake on 8 June 2001. In 2001, eggs were collected from 15 females and the resulting fry were reared to 1 g; over 30 000 fed fry were released in early June 2002. In 2002, only six spawning females, most already partially spawned, could be obtained as broodstock, resulting in less than 5000 uveniles alive in captivity at the time of writing.

The Saga Seafarms Ltd aquaculture site, located 500 m from the Sakinaw Lake outlet, reared a single generation of sockeye from the Pitt River population as an experiment that began in 1991. There were no reports of any sockeye escaping from the pen and the aquaculture site is no longer active. The site manager reported that seals and river otters were a nuisance at the site.

Habitat Restoration Activities

Logging debris has been removed sporadically from the outlet and spawning beaches of Sakinaw Lake. A log jam and other debris were removed from the outlet creek in 1972. Beach 2 was cleared of logging debris to a depth of 5 - 10 m in 1974. Lakeshore residents have continued to clear debris on a small scale by pulling wood off the bottom using snorkels and ropes. Log removal is presently underway at Beach 1 in areas where ground water moves into the lake. Drain rock was added at Beach 2 to restore spawning habitat in a 25-m by 5-m area where colder water temperature indicated upwelling ground water; unfortunately, only a single female sockeye has been observed (in 2002) at Beach 2 since the addition of gravel (G. McBain, DFO, pers. comm.).