Aurora Trout

At A Glance

Originally found in two small lakes in northeastern Ontario, the Aurora trout disappeared in the early 1960s when acid rain and other pollution disrupted its ability to reproduce. Reintroduced into both lakes in the early 1990s, the fish is today reproducing naturally in only one lake. Low water pH due to acid rain is a continuing threat. The Aurora trout was also introduced into ten other lakes, but has failed to establish reproducing populations in all but one.

About the aurora trout

Named for their beautiful colouration, Aurora trout were once a prized catch for anglers. An adult aurora will measure between 25 and 45 centimetres in length and weigh approximately 2 kilograms. The fish reach sexual maturity at between two and four years of age, and then spawn every year in nests built in groundwater springs.

What they eat

The Aurora trout feeds on a wide variety of prey including worms, leeches, crustaceans, aquatic and land-based insects, spiders, molluscs, frogs, salamanders and a number of fish species, including young brook trout.

How to recognize an aurora trout

The aurora trout looks very similar to other brook trout, lacking only the spots along its flanks and blue halos ringing the red dots. The Aurora has an olive-green to dark-brown back, iridescent steel blue and silver sides, and silvery white bellies often tinged with pink. The trout’s dorsal and caudal fins have black lines; the pectoral, pelvic and anal fins have a white leading edge and a black border. When male Auroras begin to spawn in the fall, their bellies blaze a brilliant orange and red.

Cory Trepanier

Where the aurora trout lives

Aurora trout occurred naturally in Whitepine Lake and Whirligig Lake in northeastern Ontario, and has been reintroduced to these two lakes and 10 others. Aurora trout prefer colder waters—below 20°C—and seek these out by moving to deeper water or by inhabiting groundwater springs. A water pH of at least five is necessary for the fish to reproduce successfully and thrive.

Why it’s at risk

The Aurora trout spawns only in lakes with groundwater springs, and changes in the quality or quantity of these springs can affect the fish significantly. Acid raid, the main cause of the trout’s initial disappearance from its natural habitat, continues to pose a major threat; the trout’s survival depends upon the maintenance of water pH at acceptable levels. As well, industrial activity such as logging and mining continue to impose pressures on the species.

What’s being done

The Aurora trout is designated as endangered by COSEWIC and protected under the Species at Risk Act (SARA). The fish is also protected under the federal Fisheries Act.

A recovery strategy for the Aurora trout has been drafted and is currently under review. Recovery goals include reintroducing the fish successfully to its native waters and establishing viable self-sustaining populations.

Ongoing actions include monitoring of water quality, phytoplankton, zooplankton, and benthic invertebrates in native lakes every month through the ice-free period in the native lakes, and assessment of population data. Water quality in both native lakes will be tested to determine if whole-lake liming is required to maintain adequate pH levels. The existing captive-breeding program at Hill’s Lake Fish Culture Station will be enhanced by increasing the numbers of families from which genetic material can be collected.

Consult the Recovery Strategy for Aurora Trout:
Recovery Strategy for the Aurora Trout (Salvelinus fontinalis timagamiensis) in Canada (2006)

What can you do?

The Aurora trout will get the protection it needs only if all Canadians work together to reduce threats. Find out more about Aurora trout and be aware of human-induced threats. Do your best to reduce these threats wherever possible to better protect the trout’s critical habitat. Get involved with the Habitat Stewardship Program for Species at Risk (HSP) or another conservation organization.

Background information provided by Environment Canada in March 2004.