Evaluation of a Pool and Weir Fishway for Passage of Alewives (Alosa pseudoharengus) at White Rock, Gaspereau River, Nova Scotia.


C L. Dominy




alewife, day/night samples, entrance, fatigue, fish movement, fishway capacity, hydroelectric, pool, pool and weir, spawning, tailrace, turbulent, water level, weir


A spawning run of 61,000 alewives was used in 1970 to evaluate a pool and weir fishway in Nova Scotia. Fish marked with a new color-coded, paper fastener tag in the tailrace of the adjacent hydroelectric power development took 6-7 days to move into the fishway. The rate of fish movement was faster from pool to pool within the fishway compared to the rate at the entrance. Crowding tests in the fishway pools showed that the exit rate tended to increase in a slightly curvilinear fashion with higher densities of alewives. Fishway capacity was estimated at a peak of 2,000 fish per hour with a daily maximum of 10,000. Analysis of blood lactic acid concentration demonstrated no muscle fatigue as fish passed through the fishway. This blood technique also showed that fish stopped to recover from fatigue in the two larger 'rest' pools. The need was identified for more stable water levels in the tailrace at the fishway entrance. In addition, the entrance is better located near an area of relatively quiet water rather than entirely in fast moving, turbulent water. Information is presented on the commercial alewife fishery in the Gaspereau River and on the biological characteristics of the spawning run.

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