November 27, 2013

MNR looking at ways to fight Round Goby

As published in The Erin Advocate

Arrival of the invasive Round Goby fish species in Hillsburgh has the Ministry of Natural Resources scrambling to control it, and trying to decide whether to attempt eradication with poison.

“This species is spreading throughout Ontario even faster than Zebra Mussels,” said Art Timmerman of MNR in a delegation on November 19 to update Erin Town Council on the situation.

“There is a lot of concern about what this species can do to native fish communities, in competition with them, eating their eggs and displacing them.”

The short-term response includes containment, with screens placed at dams, and shutting a bypass channel to stop fish from moving downstream.

MNR staff are working on a long term solution, which will require environmental assessment, extensive public consultation and funding by the ministry. Control measures could include frequent removal through netting, trapping and electrofishing (temporary shocking).

They could use pheromone baited traps, and combine a winter draw-down of pond levels with electrofishing, or with application of piscicide, a chemical poisonous to fish.

“This will kill anything that breathes with gills,” said Timmerman. “The effect goes until it is diluted.”

The procedure would likely include capture with electrofishing of many other local fish, which would be stored safely and re-introduced later to re-populate the affected area of the Credit River.

“Limiting the population and limiting where they can go might be your better bet, because I don’t think you’ll achieve totally eradication,” said Mayor Lou Maieron, suggesting introduction of a cold-water species like speckled trout to control gobies during the winter.

The Round Gobies are native to Eastern Europe, and were first found in Ontario in the St. Clair River in 1990, probably transported in the ballast water of ships. They are known to live in Lake Ontario and the lower sections of rivers, but their discovery in Hillsburgh last August was unusual. A dumped bait bucket is the likely source. They have also been found in Belwood Lake, part of the Grand River watershed.

They have been caught or spotted in the privately-owned ponds north of the Elora-Cataract Trailway, but surveys have shown no evidence that they have spread downstream. The species prefers the relatively warm water of ponds, which also have small mouth bass and sunfish, to the cooler flowing water favoured by trout.

“In trying to control or eradicate these animals, we’re depending completely on the good will of land owners to make that happen,” said Timmerman.