High-tech fish tagging in the Toronto HarbourFish in the Toronto Harbour are getting the high tech treatment — acoustic tagging will provide 24/7 detail on fish in the harbour.
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CARLOS OSORIO / TORONTO STAR
Maxime Veilleux, left, passes a fish to Adam Weir so he can release it.
By: Jeff Green News reporter, Published on Mon May 13 2013
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It’s a typical scene for the Night Heron — the research vessel has drawn the attention of the Toronto Police Marine Unit while unloading fish at Polson Pier.
“How big?” yells one officer before the water cruiser docks.
He hopped aboard Thursday to “inspect” the boat’s livewell, which is full of fish that will be tagged for a five-year study into the microhabitat of nine species in Toronto’s harbour.
Picking up an 11-pounder, the officer hands his cellphone to one of six research assistants from Carleton University.
“Can you take a photo?”
They’re happy to oblige, even if the picture will likely end up as bar stool lie. The finned find, however, may be headed for surgery as one of this year’s 148 fish involved in high-tech acoustic tagging study.
By the year’s end, 329 fish from nine species will have been tagged, providing location, temperature and depth details 24 hours a day, seven days a week for a full year each.
“We want to see where the fish are moving throughout the harbour, see where they’re spawning, see where they’re hanging out for the day, where they hang out at night,” said Rick Portiss, manager, restoration and environmental monitoring with the Toronto and Region Conservation Authority.
“With that information we can make management decisions on how protect areas and we can also decide where the best fishery is.”
A series of 36 receivers positioned throughout the harbour, and two outside the harbour, provide detailed data for the joint study between the TRCA, Carleton’s fish ecology and conservation physiology lab, Aquatic Habitat Toronto and the Department of Fisheries and Oceans.
On the pier, several fish have are recovering from surgery to implant the device in large bins. A few small stitches on the belly of the fish hide the acoustic transmitter, which takes less than three minutes to insert.
The fish are knocked out for the process using a small electric shock. They’re caught with a similar technique called electrofishing — essentially fishing with electric dynamite.
“Almost the same thing,” Portiss laughed. “Only the government can do this, so don’t get any ideas.”
The Night Heron, their research vessel, is equipped with special rods that drop into the water to provide an electric shock. Stunned fish float to the top where they’re netted into the boat’s livewell.
Research assistants collect the species they’re after — northern pike, largemouth bass, white sucker, carp and walleye, among others — and bring them back to shore for surgery.
The study, in its third year, is first of its kind in Lake Ontario. Traditional tagging methods only provide a snapshot in time, but the acoustic tagging will give details for not just their regular routines, but how fish handle situations unique to Lake Ontario, like cold water upwells.
“Toronto Harbour gets a big pulse of cold water” every so often, said Jon Midwood, post doctorate student from Carleton.
The water can change as much as 10 degrees in less than an hour — how the fish handle the sudden change will be part of the lab’s research. Portiss points out that information will have a real impact on how the TRCA manages the harbour.