Research Document - 2014/099

Recovery Potential Assessment for Eastern Cape Breton Atlantic Salmon (Salmo salar): Status, Past and Present Abundance, Life History, and Trends

By A.L. Levy and A.J.F. Gibson

Abstract

The purpose of this research document is to provide background information on the present abundance, status, life history, and recent trends for Atlantic Salmon populations in the Eastern Cape Breton Designatable Unit (ECB DU) and to provide information on recovery targets in support of recovery planning for this DU. Atlantic Salmon population monitoring in eastern Cape Breton has focused on five river systems: Middle; Baddeck; North; Grand; and Clyburn. Assessments on these rivers have been based on fishery-independent counts by dive surveys or at a fish ladder and/or recreational catches. Of these five populations, Grand and Clyburn have declined in adult abundance over the last 20-, 15-, and 10-year time periods. North River has declined over the last 20 years; however, the population appears to have increased during the last 10 years. Trends for Middle and Baddeck rivers are less evident; both populations appear to be relatively stable, but at abundance levels below their conservation requirements. North River was the only population estimated to be above its conservation requirement in 2011 (the most recent year available for assessment). Status of Atlantic Salmon in other rivers is based on recreational catch data and intermittent electrofishing surveys. Declining trends in recreational catch and effort are evident for many rivers across eastern Cape Breton. Low abundance observed in the recreational catch data is consistent with the results from the most recent electrofishing surveys, which indicated that juvenile Atlantic Salmon abundance was below reference values at many locations during 1996-2007 even though juveniles were widely distributed throughout eastern Cape Breton.

Recommended interim recovery targets for Atlantic Salmon populations in eastern Cape Breton have abundance and distribution components. Conservation (egg) requirements are proposed as abundance targets until the dynamics of recovered populations can be studied. Distribution targets are more difficult to quantify, but should encompass the range of variability among populations. There is the expectation that including a wider variety of populations in the distribution target will enhance short-term persistence and facilitate recovery in the long-term. Recovery targets will need to be revisited as information about the dynamics of the recovering population becomes available.

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