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Bloater Restoration 


Deepwater coregonines are a diverse group of species that once comprised an integral part of the native fish community of the Laurentian Great Lakes. Today, most deepwater coregonines are extinct or have suffered local extirpations that restrict them to Lake Superior and/or Lake Nipigon, while the shallow-water form, Coregonus artedi, persists throughout the extent of the Great Lakes.

An exception to this is bloater (Coregonis hoyi), a deepwater coregonine that currently inhabits Lakes Huron, Michigan, Superior, and Nipigon. Until the mid-1950s, bloater were an abundant forage fish in Lake Ontario but became scarce in the 1960s as a result of a dramatic population decline associated with overharvesting and invasive rainbow smelt (Osmerus mordax), alewife (Alosa pseudoharengus), and sea lamprey (Petromyzon marinus).

To address the loss of bloater, Canadian and American natural resources agencies have partnered in a restoration effort to reestablish a self-sustaining population, increase prey fish diversity, benefit the native predator restoration, and offer greater resilience to invasive species and a changing climate

However, the issue remains that we are unaware of what happens to these stocked fish following their introduction into the lake; in reality this is an issue for the 25 million juvenile fishes stocked in the Great Lakes every year. 

Acoustic Telemetry

The objectives of this research project are to determine the post-release behaviour, habitat use, and survival rates of stocked bloater in Lake Ontario through the use of acoustic telemetry. Hatchery-reared juvenile bloater (age-1, 11-23 g) are surgically implanted with acoustic transmitters that provide information about location and predation events, and then released as part of a normal stock in southeastern Lake Ontario. A total of 108 acoustic receivers (180 kHz) have been deployed 3km off the port of Oswego, NY to detect the presence and absence of tagged bloater.

Relevant Lab Members –Lydia Paulic (M.Sc.), Silviya Ivanova (PDF), Natalie Klinard (M.Sc. – alumni)


Establishing a population of deepwater ciscoes will help to achieve healthy lake ecosystem by restoring fish native to the lake and increasing biodiversity. A substantial population of forage fishes would improve food web stability through providing a trophic link between benthic production and top predators and reduce the potential for invasive species to colonize the niche that bloater would will. Successful reestablishment of hatchery-reared fish resulting from studies done using acoustic telemetry would also provide a foundation that can be used as the basis for reintroduction and management of other native species throughout the Great Lakes.

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