Striped bass population triples in Gulf of St. Lawrence

Above: Striped bass photo: Meghan Wilson/DFO


Striped bass population triples in Gulf of St Lawrence

Species went from threatened to thriving

Paul Withers · CBC News · Posted: Apr 11, 2018 6:00 AM AT

The remarkable recovery of striped bass in the southern Gulf of St. Lawrence reached unprecedented levels in 2017, according to the latest assessment from the federal Department of Fisheries and Oceans.

Department scientists say the spawning population tripled between 2016 and 2017 and is now estimated at one million fish — a 100-fold increase from the 1990s.

In addition to the population rebound, tagged striped bass from the Gulf were recovered from Rimouski, Que., north to Labrador for the first time in 2017.

In the Forteau Bay area of Labrador, catches of tens of thousands were reported.

"I think this is unusual," said Trevor Avery, a marine biologist at Acadia University who is tracking the expanded range of Gulf striped bass. "This seems to be a first-time sighting in, let's use the term, in living memory."

Until last summer, the northern limit of the confirmed distribution for southern Gulf striped bass had been the Gaspé Peninsula.

Is a warming ocean responsible?

Just why this is happening has not been definitively determined. Avery said a combination of variables can contribute, including survival of larvae, a healthier ecosystem and more bait fish.

Another key factor could be warming ocean temperatures.

"It allows things to produce faster, grow larger in shorter seasons. There are all kinds of things that are tied to temperature," said Avery.

DFO did not make any of its 11 scientists who contributed to the report available for an interview.

"The reason for this extended migration and whether it will be repeated in future years is unknown, but it may have been associated with above average sea water temperatures in the Gulf of St. Lawrence in recent years," DFO said in its report.

The comeback story

When the spawning population collapsed in the 1990s, DFO started closing fisheries.

The commercial fishery was shut down in 1996, followed four years later by recreational and Indigenous fisheries.

In 2004, Gulf striped bass was listed as a threatened species by federal authorities.

But the population came back and in 2012, First Nations food, social and ceremonial fisheries were reinstated and a recreational fishery reopened in 2013.

2017 marked the seventh straight year striped bass met species recovery targets.

Trap nets overwhelmed

For several weeks every year, the epicentre of the Gulf striped bass population is the northwest Miramichi River, where hundreds of thousands return to spawn in May and June.

That's where scientists count them, tag others and make population estimates based on models.

In 2017, modelling produced estimates ranging from 450,000 spawners up to two million. The department settled on an estimate of 994,000.

The run coincides with a commercial gaspereau trap net fishery on the northern Miramichi which is used to monitor striped bass.

'Something strange going on'

Nathan Wilbur, New Brunswick program director for the Atlantic Salmon Federation, said the striped bass explosion was part of a bizarre 2017 off New Brunswick.

"Last year there was something strange going on in the Gulf of St. Lawrence," he said, pointing to the appearance of endangered North Atlantic right whales in large numbers. "Fishermen in Newfoundland were seeing species they'd never seen before."

Wilbur argues striped bass are now so numerous it's time for a small, First Nations commercial fishery in the Miramichi. He said striped bass entering the system were already taking a toll on Atlantic salmon smolts on their way out to sea.

"With the population of spawning bass tripled, our fear is predation may have increased quite a bit as well," Wilbur said.

Recreational fishery worth millions

Jeff Wilson co-hosts the Striper Cup, an annual striped bass tournament in the Miramichi.

He said reinstatement of a commercial fishery is premature and could jeopardize a recreational fishery that he said generates millions of dollars in the Miramichi area.

"We have to be careful. The population could crash quickly," Wilson said. "We have to make small adjustments to our harvest program in order to make sure we have this fish for years and years to come."