Cod numbers in the Gulf of Alaska fall dramatically

A small Pacific cod. (Courtesy of the National Ocean and Atmospheric Administration)

A small Pacific cod. (Courtesy of the National Ocean and Atmospheric Administration)

The North Pacific Fishery Management Council, which regulates groundfish in Alaska and other federal fisheries, received some shocking news last month.

Pacific cod stocks in the Gulf of Alaska may have declined as much as 70 percent over the past two years.

The estimate is a preliminary figure, but it leaves plenty of questions about the future of cod fishing in Gulf of Alaska.

The first question that comes to mind when you hear the number of Pacific cod in the Gulf dropped by about two-thirds is what happened?

National Oceanic and Atmospheric Administration fisheries division’s Steven Barbeaux has been trying to answer that question. Barbeaux said the issue likely started with warmer water moving into the Gulf in 2014 and sticking around for the next three years.

“We had what the oceanographers and the news media have been calling the blob, which is this warm water that was sitting in the Gulf for those three years,” Barbeaux said. “It was different from other years in that it went really deep, but it also lasted throughout the winter.”

Warmer water temperatures speed up a fish’s metabolism, leading them to eat more.

“What can happen is you can deplete the food source pretty rapidly when the entire ecosystem is ramped up in those warm temperatures,” Barbeaux added.

With less food around, the size of Pacific cod in the Gulf dropped.

NOAA surveys show that cod were the skinniest on record in 2015, but fish didn’t just get smaller. Natural mortality rates also skyrocketed for some important age classes of cod.

NOAA saw a large influx of cod larvae in 2012, 2013 and 2015, signaling good fishing seasons over the next six years or so.

But between warmer water temperatures and the subsequently shrinking food supply, those fish aren’t showing up, likely accounting for a large portion of the decline.

This isn’t the first time cod stocks have taken dive in the Gulf. The fishery saw a substantial decline in the mid-2000s, but Barbeaux said this time is different.

“The difference between then and now is we don’t see any recruitment coming in. We’re hoping 2017 will be good, but we don’t have any indication yet,” Barbeaux said. “So, our surveys for those smaller fish haven’t been conducted. They’ll be done next year.”

Because of that uncertainty, the North Pacific Fishery Management Council has some difficult decisions to make at its meeting in early December.

The regulatory body made an initial recommendation in October to reduce the total allowable catch in the Gulf by 30 percent, but council member Buck Laukitis said the final decision next month could be different.

“I think it’s just really important that the public understand that’s a preliminary number, but they should also understand that there is a fairly big change coming in the cod resource,” Laukitis said. “Fishermen, stakeholders, a lot of people will be affected, a lot of industry.”

Barbeaux’s analysis will be reviewed by two advisory bodies prior to the council setting 2018 harvest levels. State fishery harvest levels will also see a reduction.

Fishermen will have a chance to weigh in, but Laukitis said the council will base its decision on the final analysis.

“We don’t overrule the science. There won’t be any miracles as far as the council doing something other than what the science advisors recommend,” Laukitis said.

Between the Bering Sea and the Gulf,  Pacific Cod account for Alaska’s second largest fishery by volume, bringing in $186 million in 2015.

Cod numbers in the Bering Sea are also trending down. It’s estimated abundance may have fallen nearly 40 percent, but the cause of that decline is not directly known.

As for the future of cod in the Gulf of Alaska, Barbeaux said that depends on recruitment over the next few years, but the Gulf is expected to see the return of La Nina, which could mean cooler waters and better conditions for young fish.

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