Chasing the Aurora: Ontario’s Rarest Trout

Don’t call it a comeback, but maybe something close to that. The Aurora Trout has a story worthy of a Hollywood film, if they made movies about fish species. This species, named after the colours of the aurora borealis (northern lights), has a truly unique pattern. Before I get into the Hollywood story, it should be noted that the Aurora Trout is not it’s own species but it is a sub-species or variant of the more common Brook Trout.

Think back to a time before the rapid industrialization of Northern Ontario; the Aurora Trout were going about their daily routine. Living their best life in two lakes in the Temagami District of Ontario, within the beautiful Lady Evelyn Smoothwater Provincial Park. The fact that a subspecies could somehow exist in only two lakes in Ontario was baffling to me, as there are other subspecies of fish that are more widespread than in a few lakes. It turns out that these two lakes were isolated after continental glaciers receded from the area roughly 10,000 years ago. Back to the story, during the 1950’s, the scourge that was acid rain had the Aurora Trout in its sights, and it pulled the trigger. The acid rain was caused by metal smelting in Sudbury with the boom of the mining industry, and the small lakes of Whirligig Lake and Whitepine Lake had little natural buffering qualities. The pH levels in these lakes dipped to around pH 5.0, which is a threshold for their reproductive success. The Aurora Trout was extirpated from its natural range.

This story would have ended right here, if not for the work of Paul Graf, a hatchery manager from the Ministry of Natural Resources and Forestry. In 1958, a spawn collection was done from one female from Whitepine Lake and two from Whirligig Lake. These 3644 eggs represent the lineage of all Aurora Trout in existence today. After the collection of these samples, lake acidification continued and eventually made reproduction in these lakes nonviable. This means that at one point, all the Aurora Trout on the face of Planet Earth were housed at a hatchery near Hill’s Lake, Ontario.

This is where the comeback starts. Acid rain caused by mining operations in Sudbury largely subsided as chemical scrubbing technology improved and the mining industry was in decline. This meant that the acid rain effectively stopped, but Whirligig Lake and Whitepine Lake were still too acidic to support Aurora Trout. To return the lakes to their pre-industrial pH levels, liming was started on the lakes and proved to work as the pH levels increased and levelled off at pH 5.3-5.4 from 1997-1999.

This meant that the rarest trout in Ontario could be reintroduced to its original two lakes from the population at the hatchery. This occurred and was successful, and additional stocking was done in other lakes around Ontario. Today, there are 12 lakes in Ontario that contain Aurora Trout, nine of these are stocked by the Ministry of Natural Resources and Forestry for recreational fishing usage. Of these nine, only three are open for recreational fishing per year and are on a rotating basis as to help keep stocks healthy and add a potential for bigger fish.

Aurora Trout present a unique opportunity in Ontario, one that is hard to pass up. As always, make sure to check the regulations for the Fisheries Management Zone you are angling in, and make sure you bring your Sab Spinner. For your ease, the lakes open for Aurora Trout during the 2020 seasons are Carol Lake in Beulah Township (FMZ 10), Lake 21 at 47°37’N., 80°57’W. (FMZ 10) and finally, Liberty Lake in Aston Township (FMZ 11).

Make sure to check out the other content on http://www.OntarioAngler.ca, buy a fishing license and don’t forget your Sab Spinner.

Keep Casting,

Nate