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COSEWIC Assessment and Update Status Report on the Aurora Trout in Canada

Special Significance of the Species

The Aurora Trout is a unique subspecies of the Brook Trout that is native to only two lakes in the entire world. Valued for its beauty and rarity, it was the only fish stock out of hundreds that were extirpated by acidification in Ontario that has been preserved through captive breeding.


Evaluation

The Aurora Trout is a unique subspecies of Brook Trout endemic to two lakes in northeastern Ontario. By 1967 it had been extirpated from both lakes as a result of anthropogenic acidification. It was preserved through captive breeding done by the Ontario Ministry of Natural Resources using brood stock maintained in one sanctuary lake and at a provincial fish culture facility. Reproducing populations were re-established during the 1990's in both native lakes following restoration of water quality by whole-lake liming, but it is not yet certain that pollution levels are low enough to protect the lakes from reacidification. Naturally reproducing populations that were established in two well-buffered non-native lakes were extirpated. Illegal harvesting was documented on those lakes. If Aurora Trout are reintroduced there, consideration should be given to increased protection from illegal harvesting and to protecting the watersheds from potentially harmful industrial activities (eg. mining, logging). The continued survival of wild self-sustaining aurora trout populations depends on protecting their lakes and watersheds from harmful anthropogenic alterations.

Over the past decade great progress has been made in restoring the Aurora Trout to its native habitat, but continued survival of the aurora trout requires a strong commitment to human intervention. It is not yet certain that the water quality in the native lakes will remain suitable for Aurora Trout without additional whole-lake liming. The reproducing populations established in two non-native lakes have recently been extirpated. Given the limited distribution and the current uncertainties regarding continued maintenance of habitat quality, the Aurora Trout should still be considered an endangered species