Reinforcement of American eel Anguilla rostrata populations in eastern Lake Ontario tributaries, Ontario, Canada

  • Published source details Reid S.M. & Hogg S. (2014) Reinforcement of American eel Anguilla rostrata populations in eastern Lake Ontario tributaries, Ontario, Canada. Conservation Evidence, 11, 29-33.


A dramatic decline in American eel Anguilla rostrata abundance led to the species being assessed as endangered in Ontario (Canada) and the closure of fisheries. As part of efforts to recover populations, four million eels (glass eels and elvers) were released over a five year period into the upper St. Lawrence River and Lake Ontario. A large-scale electrofishing survey of eastern Lake Ontario tributaries was undertaken to assess the distribution and survival of the released eels. Four hundred and seventy-six eels were collected from 37 sites along seven watercourses. Eels were well-distributed along five rivers close to the release site. By contrast, distribution along the two largest rivers surveyed was restricted to a few kilometres upstream of Lake Ontario because of multiple impassable dams. The average length of eels caught in these two rivers was 40 mm shorter than eels in other watercourses. Eels were not detected in five smaller and colder creeks further west. 

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