Most smelt in northern Ontario are an invasive species and they're making lake trout smaller

Jonathan Migneault · CBC News

· Posted: May 02, 2025 12:27 PM EDT | Last Updated: 11 hours ago

Lake trout successful immoderate bluish Ontario lakes aren't arsenic large arsenic they utilized to be, and a geneticist says it's due to the fact that of different fish, you apt didn't cognize was an invasive species.

Christian Therrien, a researcher astatine the University of Waterloo, says caller findings person shown that erstwhile water trout devour rainbow smelt – which aren't autochthonal to bluish Ontario lakes – it tin pb to bosom issues and thymine deficiency.

"I'll usage Lake Wanapitei arsenic an example. My gramps is saying backmost successful the time we utilized to drawback immense Titanic water trout, you know, 5 feet long. And present you person a hard clip getting them implicit 24 inches," Therrien said.

"We are learning that successful immoderate instances rainbow smelt are having an impact connected our autochthonal species. Some populations they don't look affected, immoderate they do. It's going to necessitate much probe to find what the affects are province-wide."

Therrien says determination is immoderate grounds that determination erstwhile was a native smelt colonisation successful bluish Ontario, on the Ottawa River and up successful the Lake Temiskaming area.

But helium says astir of what is present caught successful creeks and rivers each outpouring is an invasive species, immoderate which originate successful the Gulf of St. Lawrence and the others that were introduced by humans into Crystal Lake successful Michigan successful 1912.

"They showed up successful the precocious Great Lakes by astir the 1950s and past were dispersed thereafter," Therrien said.

Therrien said it would beryllium astir intolerable to region invasive smelt from the lakes successful which they person dispersed implicit the past century.

But a squad of researchers from the University of Waterloo is moving to place the antithetic invasive smelt taxon successful the portion and find retired precisely however they spread.

"We don't adjacent truly cognize precisely however they managed to invade it and dispersed passim the province," Therrien said.

"So that's truly the main extremity of our task present is to find however they got here, their dispersed and perchance beryllium capable to forestall invasive taxon invasions and their spread."

He said they are besides moving to amended anglers astir smelt to guarantee they aren't dispersed to caller lakes.