Stunning Preliminary Report Shows Gulf of Alaska Cod Stocks Down By a Third From Expected Levels
SEAFOODNEWS.COM [Seafood News] by Peggy Parker – October 4, 2017
This story has been updated for accuracy and recent developments.
A presentation by NOAA Fisheries shocked committee members at the North Pacific Council meeting with the message that preliminary numbers from the latest survey show the lowest estimate ever of Pacific cod in the Gulf of Alaska.
The presentation showed that cod year classes for 2012 and 2013 were essentially wiped out, and failed to show up in the 2015 survey. The disappearance of these year classes coincided with the extended period of high water temperatures in the Gulf of Alaska in 2014-15. This was the time the ‘blob’ was off the Pacific coast. As a result, Pacific cod TACs are likely to be significantly less for 2018.
Pacific cod, along with rockfish, is the money fish in the Gulf of Alaska. A large cut in cod TACs to prevent overfishing will have a large impact in the Gulf.
The presentation was made yesterday to the Science and Statistical Committee and the Advisory Panel of the North Pacific Fisheries Management Council, a day before the Council convenes its week-long meeting.
Presented by Dr. Steve Barbeaux, research fisheries biologist at NOAA Fisheries in the Alaska Fisheries Science Center in Seattle, the data showed recruitment failures in 2013-2016. A high abundance of cod larvae that showed up in the survey in 2013 never made it to the bottom trawl survey in 2015.
The presentation uses data from the most recent Gulf of Alaska cod survey in an assessment model to estimate the abundance (numbers) and biomass (weight) of Pcod in the area.
It shows there has been a 71 percent decline in abundance since 2015, and an 83 percent decline since 2013. In weight, it shows a 58 percent drop in the biomass since 2015, and a 78 percent decline since 2013.
Barbeaux noted that the ABC estimates generated from last year’s models without the new survey data suggested a 2018 ABC of 79000 mt was likely too high and could potentially lead to overfishing if fully utilized.
Preliminary model runs for this year using the new survey numbers and fishery catch data suggest a 60-85% reduction in ABC for 2018. However these models have not yet been vetted through the extensive review process and may change.
A more thorough assessment report, its data, and models used on it will be reviewed by the SSC, the stock assessment team, and the Groundfish Plan Team before the Council meeting in December, when specs are set.
In 2015 there were record high temperatures in the Gulf — it was the year that the strange “blob” of warm water in the North Pacific was at its hottest and most expansive, affecting waters as far north as the Bering Sea. it has cooled down now so that ocean temperatures are now closer to, although still warmer than, the 1996-2016 average range.
Barbeaux accessed other surveys — a longline survey showing a 53% decline from 2015 and a large mesh trawl survey that showed P-cod abundance trends were down for both 2015 and 2016.
He looked at P-cod bycatch in the pollock fishery and found that those numbers had significantly decreased.
When stomach contents were looked at, the prey weight was “down to lowest measured in Pacific cod stomachs in 2015.”
In summary, Barbeaux noted that in 2015, “Warmer temperatures were throughout the year and water column; higher metabolism in higher temperatures lead to higher forage requirements, while there were indications of lower forage amounts. With a final conclusion that the combination of that could have lead to higher natural mortality for these years for the 2012 year class.”
2015 was the first of three years in which there were large die-offs of fish-eating birds, with reports that the bodies found were emaciated. There were also widespread breeding failures in 2016.