Local anglers help out with salmon study

[Spiel]

Local anglers help out with salmon study

 

 

April 11, 2008

Doug Edgar / owensoundsuntimes.com

 

 

 

Some local anglers are being recruited to help with a study that could show how far chinook salmon range in Lake Huron and Georgian Bay by analyzing fish ear bones.

 

The study’s findings could eventually have an impact on how the fishery is managed. If fish stay mostly in their local area — say if a salmon from the Sydenham River remains in southern Georgian Bay — the fishery managers will have a relatively easy time controlling fish in that area. But if Georgian Bay fish journey into the main part of Lake Huron, the North Channel, or even Michigan’s Saginaw Bay — while another fish from the main part of Lake Huron makes its way to Owen Sound — management gets a lot more complicated.

 

But before any of that gets figured out, people like University of Western Ontario researcher Stephen Marklevitz have to round up some fish heads.

 

Marklevitz was at the April meeting of the Sydenham Sportsmen’s Association to explain the project and hand out fish collection kits to six volunteers, who are each asked to collect five salmon heads. He made a similar presentation to a club in Sarnia and plans to visit the Lake Huron Fishing Club and the Bruce Peninsula Sportsmen’s Association. He’s handing out kits to volunteers to ensure all the information needed is recorded and because researchers can only afford to do so many tests. He’s not looking for unsolicited fish heads.

 

Since salmon move toward their home streams to spawn in the late summer, the researchers want the samples from earlier in the year — into July, or maybe a bit later.

 

Another part of the study starts with analysis of otolith samples taken from fry-sized chinook collected in rivers around Lake Huron. Fish from rivers in different geological areas are expected to show different trace elements in their otoliths.

 

As a fish ages its otolith is laid down in layers, Marklevitz explained.

 

“It’s like writing a book in pen. You can’t go back and erase that first part, so we can go back and read these things much like a book,” he said in an interview this week. “We can look at the first page when the fish are babies, or eggs actually . . . and you can look at them right through to the time they die.”

 

That means researchers should be able to analyze the ear bone of an older fish and compare the trace elements found in it with what they know from the fry samples and determine where the older fish hatched.

 

“It is an up-and-coming technique, but it has been proven already,” Marklevitz said.

 

A technician removes the otolith from the donated fish head. It is polished and prepared and then a laser is used to vaporize part of it, starting from the centre and working out. The gases given off are then analyzed.

 

While most fish stocked in Ontario are marked by having fins clipped, not all are, he said. The otolith technique allows researchers to figure out where wild-born fish — none of which are clipped — are from too.

 

“It’s going to allow us to look at things in much finer detail than in the past,” he said.

 

It’s believed most salmon now caught in Lake Huron are wild-born, he said. The study may help solve the mystery of where hatchery-raised fish are going, or if they’re behaving differently than the wild ones.

 

While Marklevitz and his group are after the volunteer anglers’ fish heads, David Gonder of the MNR’s upper Great Lakes management unit in Owen Sound wants the tails, with some of the spine included. It’s part of the MNR’s ongoing study of the balance between hatchery fish and those that reproduce naturally.

 

While Ontario uses fin clipping to mark hatchery fish, Michigan uses the antibiotic oxytetracycline, or OTC. The chemical quickly leaves the flesh, so there’s no risk in eating it, but it stays in the skeleton and will glow when exposed to ultraviolet light.

 

The vertebrae sections will be sent to Michigan for analysis, Gonder said.

 

Since fish have to be killed for both studies, it makes sense to run them together, he added.

 

 

out for trout

 

Organizers are getting ready for the region’s first large fishing derby of the season.

 

Tickets were to go on sale Friday for the Georgian Triangle Anglers Association’s 28th annual Spring Trout Derby, which is to run from April 25 to May 4.

 

Tickets are $20 and are available from some GTAA members and at locations throughout the southern Georgian Bay area, according to derby chairman Gary Lawrence.

 

The club also has information posted at http://www.meaford.com/fishbyte/

 

First place in rainbow is $1,000, second is $500 and third is $250. The top brown trout and salmon fetch $100.

 

According to the website, tickets are available and there will be a weigh station at Garnet’s Esso, 13 Sykes St., Meaford, with more announcements to come. Net proceeds from the derby go to fishery enhancement projects.

 

 

lake level update

 

Lake Huron and Lake Michigan are seven inches (17.5 centimetres) lower than they were at the same time last year, according to data posted on the Great Lakes Information Network, while Lake Superior is seven inches (17.5 centimetres) higher. Lake St. Clair is four inches (10 centimetres) lower, while Lake Erie is an inch (2.5 centimetres) lower and Lake Ontario is an inch higher. Lakes Superior, Michigan-Huron, St. Clair and Erie are predicted to rise two to three inches (five to 7.5 centimetres) over the next month or so, and Lake Ontario is projected to rise six inches (15 centimetres). Lake Superior is forecast to stay above last year's water levels through August, while the remaining lakes are forecast to remain at or below their levels of a year ago over the next several months.