Asian carp capable of breeding in Great Lakes: USGS scientists

Captured grass carp at Dept. of Fisheries and Oceans research lab in Burlington, ON (Andrew Reeves)

Anyone doubting whether Asian carp could successfully breed in the Great Lakes watershed got their answer Monday as researchers with the U.S. Geological Survey and Bowling Green State University in Ohio announced four grass carp were found to have lived and bred in the Sandusky River, a tributary of Lake Erie.

This is a critical milestone. Canadian and US scientists and policy makers have been holding onto a last hope that, should the destructive invasive species make its way into the watershed, they may not be able to survive or breed in the cold, deep waters of the Great Lakes.

But scientists and researchers threw cold water on that idea with the revelation Monday that the fish, the four grass carp that were captured in October 2012 by commercial fishers, had spent their entire lives in the Great Lakes basin and were not introduced as sterile specimens for stocking purposes.

Duane Chapman, a USGS fisheries biologist, told reporters bluntly: “This is bad news.”

“It would have been a lot easier to control these fish if they’d been limited in the number of places where they could spawn,” Chapman said.

While it won’t be impossible to control the species, it does make the work of enforcement officers more difficult. Luckily, the administration of U.S. President Barack Obama has understood the severity of the issue and has committed more than $200 million to combatting their spread.

Part of the issue facing scientists and researchers is identifying and controlling vector points between the Mississippi River watershed and the Great Lakes watershed. Scientists know of many such vector points, but they are attempting to plug an unknown number of leaks in unknown locations at unknown times.

“These findings are significant because they confirm recent USGS research indicating that shorter rivers, like the Sandusky, are potential spawning sites for grass carp and other Asian carps as well. The study may also provide resource managers an opportunity to address the spread of grass carp before it becomes problematic,” Chapman said in a news release on the USGS website.

Other grass carp have been caught in tributary rivers to the Lake Erie, such as two grass carp seized by federal Department of Fisheries and Oceans scientists in the Grand River on the Ontario side of the lake. But unlike those grass carp, the four specimens analyzed from the Sandusky River were capable of breeding.

Scientists used bones inside the fishes’ heads called otoliths that provide a detailed chemical analysis of the water a fish has spent its life in.

“Analysis of those bones indicates that the four captured grass carp had lived in the Sandusky watershed their entire lives,” according to the USGS release. “Scientists ruled out the possibility that the fish originated from a fish farm by comparing their otoliths to those from reference pond fish.”

Here in Ontario, Natural Resource Minister David Orazietti fielded questions from opposition critics Monday for the lack of action on the Asian carp file in the latest Great Lakes Protection Act legislation brought forward by Environment Minister Jim Bradley this year.

“People are concerned about serious threats to our Great Lakes, and your government seems paralyzed as far as taking any action,” said Progressive Conservative MPP Toby Barrett.

“You talk about your strategy, your goals, your intentions, setting up panels but no action where immediate action in conjunction with Great Lakes states and the federal government is crucial and long overdue,” he said in the House.

Read the full story at Alternatives Journal.