Bluefin tuna being caught in more northern Atlantic Ocean waters

Scientists say warmer ocean waters are leading to bluefin tuna being caught in more northern Atlantic Ocean waters than ever before.

Fishermen have caught the giant fish over the past several weeks between Greenland and Iceland.

Bluefin traditionally follow mackerel up the coasts of Canada and Ireland but have never been seen between Iceland and Greenland. Those waters are usually too cold for tuna and its prey.

Dr. Brian Mackenzie is a professor marine fish population ecology at the Technical University of Denmark. He is from Dartmouth, Nova Scotia and has spent much of his life in Denmark studying fish populations.

“The fact they turned up in east Greenland was indeed a surprise,” he said. “The fish were caught as bycatch in an exploratory mackerel fishery.”

The number of the giant tuna caught is not huge — only about 20 or 30, have been caught in the northern waters. But the growing number is alarming to scientists, according to professor Jeffrey A. Hutchings from the Canada Research Chair in Marine Conservation and Biology at Dalhousie University.

“We really see the warming being quite prominent in northern waters such as between Iceland and Greenland and our own Canadian arctic,” he said.

There’s money to be made with the big fish. The commercial tuna fishery is a lucrative one with a prime 200 kilogram Bluefin selling for a world record $173,600.

Hutchings says this is not just about tuna.

“We will see some strange new things in our waters,” he said. “In fact, we have already started to see some of that, species off the Caribbean and very southern waters are now showing up with greater regularity off the east coast of Canada.”

MacKenzie says scientists have other questions about this dramatic change as well — primarily what do these shifts mean to fishermen and their industry?

“We have to find out how frequently or regularly this is going to be,” he said. “But certainly is this is going to be a regular phenomenon we would very much like to do some investigation including tagging to find out where they are coming from."