Evaluation of Hatchery versus Wild Sockeye Salmon Fry Growth and Survival in Two British Columbia Lakes

Abstract

We evaluated the relative success of sockeye salmon hatchery fry stocking in two British Columbia-Alaska transboundary lakes (1,622-ha Tatsamenie Lake and 492-ha Tahltan Lake). Fry stocking began in the late 1980s and is still under way. During the study period, survival patterns in the two lakes were different. At Tatsamenie Lake, wild egg-to-fry survival was higher than hatchery egg-to-fry survival (11.3% versus 4.3%) and wild egg-to-smolt survival was higher than hatchery egg-to-smolt survival (5.8% versus 2.5%). We found no relationship between fry survival and stocking date, spawner abundance, or food availability in Tatsamenie Lake, but we did find a significant positive relationship between early-spring fry length and egg-to-fry survival. Also, we found that in net-pen experiments, larger fry survived better. From this, we concluded that hatchery fry stocked into Tatsamenie Lake may suffer from size-mediated mortality and that net-pen supplemental feeding could be used to overcome this problem. However, because eggs used for hatchery production come from the lake, fry stocking can only be justified when hatchery fry survival exceeds wild fry survival. At Tatsamenie Lake, this goal has not yet been attained. At Tahltan Lake, wild egg-to-fry survival was lower than hatchery egg-to-fry survival (1.5% versus 6.3%) and wild egg-to-smolt survival was lower than hatchery egg-to-smolt survival (3.6% versus 12.8%). Hatchery fry release date and food availability both failed to explain these differences in fry and smolt survival at Tahltan Lake. However, there was a strong negative relationship between total female escapement and wild egg-to-smolt survival. This supported the results of an earlier investigation, which suggested that Tahltan Lake was spawning-site limited. We concluded that at Tahltan Lake, hatchery fry stocking increased smolt numbers, is biologically justified, and should be continued.

The Productivity and Viability of Snake River Sockeye Salmon Hatchery Adults Released into Redfish Lake, Idaho

“…Hyatt et al. () reported wild Sockeye Salmon egg‐to‐smolt survival for Tatsamenie and Tahltan lakes in British Columbia as 5.8% and 3.6%, respectively. The SARs were also lower than those for northern populations in British Columbia and Alaska (range, 1.34% to 3.4%: Bradford ; range in Chilko Lake, British Columbia, 2% to 5%: DFO ) and upper Columbia River populations (range, 0.67% to 9.43%: Williams and Smith ; range, 0.2% to 23.5%: Williams et al.…”

An Age‐Structured Integrated Assessment of Chinook Salmon Population Dynamics in Lake Huron's Main Basin since 1968

“…We did not automatically include lower survival of stocked fish in the SCAA model because, as previously stated, there was no information available to suggest how survival might differ between stocked and wild fish or over what age-classes survival rates may be different. Further, some research has found stocked fish to have higher survival than wild fish (Hyatt et al 2005), so we did not feel comfortable simply making an assumption as to what survival rates were for stocked and wild fish.…”

“…It is entirely conceivable, perhaps even probable, that stocked Chinook salmon may have lower rates of survival than their wild counterparts, particularly during the first year of life. Several studies conducted on salmon species have indicated wild-produced fish have greater rates of survival early in life than stocked fish (Jonsson et al 2003;Saloniemi et al 2004;Hyatt et al 2005). If survival of stocked Chinook salmon is lower than that of wild fish in Lake Huron, than the estimates of wild reproduction of approximately 10 million fish may be extremely biased, and, as a consequence, our estimates of age-0 natural mortality rates are probably too large as well and partly function to reduce abundances to more appropriate levels.…”

A review of Pacific salmon hatchery programmes on Hokkaido Island, Japan

“…Nickelson et al, 1986;Hyatt et al, 2005), and then compare hatchery programmes with other management tools. The latter should include spawning-bed enhancement (Merz et al, 2004), rehabilitation of channelized streams , and improvements to access for migratory fish (Sagawa et al, 2004), but fisheries management should be implemented more actively.…”