Research Document 1998/39

Status of Atlantic salmon in Salmon Fishing Area 21, in 1997, with emphasis on the upper LaHave River, Lunenburg Co., Nova Scotia

By P.G. Amiro and E. M. Jefferson

Abstract

The status of Atlantic salmon spawning escapement for 1997 in the LaHave River above Morgan Falls relative to conservation is presented. The status of stocks in other rivers of SFA 21 is inferred from reports of recreational catches and a distribution of probable angling exploitation rates estimated for the LaHave River. A count-based estimate of the production of wild smolts above Morgan Falls in 1997 indicated about 16,520 or 0.66 smolts per 100 m². Return rate of hatchery smolts was the lowest in the twenty-four year record. Egg deposition above Morgan Falls in 1997 was 54% of the conservation objective of 1.96x10⁶ eggs. The modal deposition for the entire LaHave River basin was 35% of the basin-wide required conservation escapement of fish and 53% of the basin-wide required deposition of 4.74x10⁶ eggs. Increase in egg deposition relative to escapement was due to a decrease in male hatchery fish. The most probable pre-fishery abundance for eleven other rivers of SFA 21 was 3,117 salmon (1,829 - 5,289; 5^th and 95^th percentiles) and the most probable spawning escapement for these rivers was 2,221 fish, a 58% decrease from 1996. Status of stocks for SFA 21 rivers is uncertain because of acidification resultant of acid precipitation and the undetermined effectiveness of standard conservation requirements. The 1997 LaHave River angling catch rate was 34.7% and exploitation was 29%. Forecasts to Morgan Falls for 1998 indicate a deficit above Morgan Falls assuming a hook-and-release fishery for salmon (≤ 63 cm) and retention of grilse (≤ 63 cm) below Morgan Falls. No harvest (exploitation) is available for 1998 for a risk neutral (50^th percentile) chance of achieving conservation escapement. Short-term prognosis for the LaHave River relative to the interim conservation requirement was not favorable. The long-term prognosis was not expectant of increased returns.

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