By Natalie Musseau

FOR THE SOU’WESTER

It’s not everyday you hear of someone doing a blood test on a fish.

But that was one of many tests Fisheries and Oceans scientists were conducting on samples of cod caught just off Port aux Basques on May 24 and 25.

Local fish harvesters Charlie and Fred Riles were willing to help them accomplish their goals. The seasoned Sentinel fishers brought several containers with live cod to shore for the research.

The four scientists gave a couple dozen cod thorough physicals in their mobile lab to help determine why the cod population isn’t rebounding as quickly as expected and why the natural mortality numbers are high.

The scientists are also comparing the northern and southern gulf stocks for clues.

Lead scientist Catherine Couillard explained the stocks are geographically close and experience many of the same conditions, which makes them easy to compare.

The northern gulf stock, off Newfoundland’s west and southwest coasts, is in better condition than the southern gulf stock, which runs along the southeast side of Nova Scotia. The DFO biologists, from the Maurice Lamontagne Institute in Mont Joli, Que., are trying to find out why.

Charlie Riles said he doesn’t know what it might mean for the future of the local cod fishery, but it could help improve things for local harvesters.

The scientists visited Port aux Basques and Cape Breton last fall and did similar work with cod then. Cod are at peak condition in the fall, but become thin over the winter, reaching their lowest point in the spring. That’s why the scientists were in both locations again last week.

They are looking for indications of any factors that may be working together to make the stock less productive, such a chemical exposure, disease, condition, or other factors.

Couillard said it isn’t likely to be something obvious. She explained they are looking for some small indication from which to form a hypothesis to test in a controlled laboratory.

She said they are trying to find out what factors may be working together to keep the stock from reproducing as well as it might, and why so many fish are dying from non-fishing related causes.

The tests include a physical examination of the live fish, which has been anestitised, as well as blood tests and eventual dissection of the fish. They look at hormone levels, weight, sexual maturity, general health and more.

The next steps in the research will depend on what they find once the data gathered is analyzed.

(Natalie Musseau is a journalist with Transcontinental Media’s Gulf News, which is a contributor to the Sou’Wester.)