We apologize for the smell, but it’s natural – Ottawa Citizen
Byline:Tom Spears
Publication:Ottawa Citizen
Date:Tuesday June 7th, 2011
Summary
People walking along the Rideau Canal between Old Ottawa South and downtown have been reporting large numbers of carp, suckers and smaller fish, belly-up and covered with flies.
Experts haven’t pinpointed a cause, but suspect it’s a natural event.
Larry Raubach has lived two blocks from the canal for eight years and says he’s never seen anything like it. He was sitting on a bench with his girlfriend near Clegg Street on Saturday when she noticed dead fish near the edge.
“We counted around seven.” They walked downstream, crossed a bridge – more dead fish.
“One was 30 inches long, that’s not an exaggeration. Bloated and just enormous. Counted a bunch more fish and on the way back we stopped on the Pretoria Bridge and counted a few more.”
The warm weather didn’t help the fish carcasses smell any nicer.
“I said to her, ‘It’s got that dead fish smell.’ That was even before we saw anything.”
Their total on a short walk was 19 fish.
Citizen editor David Watson counted a dozen dead carp from Pretoria to Bank Street on Saturday – including three in the little inlet by the Canal Ritz restaurant – and also about a dozen suckers and sunfish. He figures the carp were in the range of six to 12 pounds, and had flies all over them. “It’s kind of disgusting,” he noted.
But does it mean the river is in trouble?
Fish biologist Steven Cooke of Carleton University said fish die at this time for year for many natural reasons: Stress from the water warming up, reproduction, and natural fish diseases. “It’s a visibility issue,” unique to the canal he said: “The wind will push them (dead fish) in one of a few directions, and all of those directions have people walking around them.”
As well, there’s little chance for predators such as snapping turtles or raccoons to eat the dead fish because of the canal’s vertical walls. Chemical spills can also kill fish “but there’s no evidence to suggest that that’s the case” this time.
“I noticed this too, in the locks back of Parliament Hill about a week ago,” said Ottawa naturalist Dan Brunton. “Big, stinking, very dead carp.”
He suggests a possible oxygen problem upstream, as low oxygen regularly kills carp during the winter in Mud Lake, in the Britannia area.
The bodies were intact and the fish probably died nearby, he noted. “Hard to imagine that if they’ve travelled through Hog’s Back Falls.”
He added that carp are invasive fish brought to Ontario in the 1880s. “Invasive organisms place second only to habitat loss as the greatest global threat to native biodiversity.” Suckers and sunfish, however, are native.
“I suspect there’s nothing to worry about beyond the obvious olfactory issue of rotting carp below Parliament Hill.”
Ottawa Riverkeeper Meredith Brown said she’s hearing “reports about smelly carp and small die-offs in the Ottawa as well as the Rideau.”
The Ontario Ministry of Natural Resources says carp normally grow up to 75 centimetres and 3.5 kilograms (a little over seven pounds) but the Ontario record is over 38 pounds.