Predicted impacts of altered water temperature regime on Glendale Creek pink (Oncorhynchus gorbuscha) fry / by B.G. Shepherd.: Fs97-4/1782E-PDF

"As part of the feasibility studies associated with the development of an enhancement program for the Knight Inlet region of British Columbia, the potential problem of premature emigration of pink fry from a proposed spawning channel was addressed. This problem was tentatively evaluated using onsite temperature and fry migration data collected over the 1982-83 incubation and emergence period. Water temperature monitoring studies confirmed that Tom Browne Creek surface water was consistently warmer by up to 4.5° than Glendale Creek water. Subgravel water temperatures were found to track surface water temperatures in a buffered fashion, with a diurnal lag of 2-4 hr. Subgravel temperatures could be as much as 4°C different than surface temperatures, but generally were 0.5-2.0°C colder May through September and 0.5-1.0°C warmer November through February. Juvenile trapping in the spring of 1983 indicated that pink and chum fry emigrated from the Tom Browne section 2-3 wk earlier than from the Glendale section; no significant differences or trends in fry length, weight, or condition were noted between systems or over time. Other species of salmon captured and sampled included coho fry and smolts and, sockeye smolts. There were also incidental catches of juvenile and resident cutthroat and rainbow/steelhead trout, Dolly Varden fry, sticklebacks, cottids, and lamprey larvae and adults. Comparison of the subgravel temperature data and the fry migration data indicated that pink fry incubated in Tom Browne water could emigrate 3-7 wk in advance of pink fry incubated in Glendale water. A review of the available literature indicated that this degree of advancement should have a nil or perhaps even beneficial effect on survival. This conclusion is tempered by a call for more detailed studies to fill data gaps"--Abstract, page iv.

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