Saving Seafood

Understanding Ocean Changes and Climate Just Got Harder

March 24, 2020 — The following was released by NOAA Fisheries:

A new study shows that two important indicators for understanding and predicting the effects of climate variability on eastern North Pacific marine ecosystems are less reliable than they were historically. This finding has important implications for fisheries and ecosystem management from Alaska to California.

Until recently, oceanographers and fishery biologists summarized and understood complex and
long-term relationships between regional fish stock productivity and ocean climate patterns using the Pacific Decadal Oscillation index (PDO) and the North Pacific Gyre Oscillation (NPGO).

The PDO accurately described the climate pattern north of 38 degrees N, and the NPGO described the pattern S of 38 degrees N. These two indices captured climate patterns that dominated North Pacific ecosystems for much of the 20th century.

“We were able use these indices to describe changes in collective environmental features including sea surface temperature, sea surface height, sea level pressure, salinity, chlorophyll-a, and ocean nutrients. They also helped us understand and predict changes in the productivity of species like plankton and fish that are sensitive to long-term weather patterns without having to understand specific relationships between individual species and their environment,” said Mike Litzow, NOAA fisheries oceanographer and study lead. “We could count on these indices as reliable tools to summarize this broad suite of climate-biology-relationships.”

Read the full release here

Researchers try to understand why Pacific cod stocks are crashing in Gulf of Alaska

May 31, 2018 — On an island about 4 miles off of Kodiak, marine scientists working with the University of Alaska are trying to figure out why Pacific cod stocks are crashing in the Gulf of Alaska.

And, how climate change may be affecting the fish when they’re young.

Mike Litzow and, his wife, Alisa Abookire, try to pull in a beach seine on a soggy gray day on Long Island. But, they catch more seaweed than fish as they slowly sink deeper into the shore’s mud.

“We have to get some kelp out, Liz,” Litzow said. “Oh no, it’s the freaking motherload. This will be our day right here if we aren’t careful.”

This isn’t a normal fishing trip.

The marine scientists are collaborating on a study for the University of Alaska Fairbanks to figure out why Pacific cod stocks are declining in the Gulf of Alaska and how warming waters may be affecting the species when they’re young.

Read the full story at KTOO 

 

A new study looks at why Pacific Cod stocks are crashing in the Gulf of Alaska

February 14, 2018 — A new study in Kodiak will hopefully shed some light on what Pacific cod go through when they’re young.

“We don’t know how they do in the winter. Where they are. What they are eating. What their energetic requirements are.”

One of the leaders of the project, Mike Litzow is a researcher for the University of Alaska Fairbanks based in Kodiak.

He said the recent crash in the Pacific cod population in the Gulf of Alaska was a wake-up call that there’s a lot to be learned about the early life stages of Pacific cod.

A few years ago a body of warm water settled in the gulf and it may have made it difficult for juvenile cod to survive.

“The operating hypothesis right now is that you can warm the temperatures up and they’ll survive if there’s enough food, but there wasn’t enough food to meet those requirements.”

The National Marine Fisheries Service, according to Litzow, recently found that the Pacific cod population had dropped by about 60 percent since 2015.

The North Pacific Fisheries Pacific Council reduced the amount of Pacific cod that can be caught by commercial fishermen in the Gulf of Alaska by about 80 percent because of the crash.

The decrease in cod will be hard for Kodiak fisherman because Pacific Cod is one of the bigger fisheries in the region.

Litzow thinks Kodiak will have to face the possibility that more fishery disasters could be in its future because of climate change.

Read the full story at KTOO

 

Why are Pacific Cod Stocks Crashing?

February 13, 2018 — “The status of Pacific cod is probably the biggest fishery issue facing Kodiak right now, with the quota cut 80 percent for 2018,” said Mike Litzow, a University of Alaska Fairbanks associate professor at the Kodiak Seafood and Marine Science Center.

Pacific cod stocks have collapsed, possibly because recruitment (production of young fish to enter the population) has been very low during a recent string of incredibly warm years in the Gulf of Alaska, he said.

Scientists don’t know why cod stocks are shrinking. The leading hypothesis is that warmer temperatures increase the metabolic rates of young cod, and their food sources don’t supply enough energy.

There’s a sticking point—there’s not enough data to test the theory. Studies of fish ecology and population dynamics in Alaska are overwhelmingly conducted in the summer. Almost nothing is known about wintertime ecology of juvenile Pacific cod.

To help provide answers, Litzow and fisheries oceanographer Alisa Abookire embarked on a pilot study this month to collect information about habitat use, diet and energetics of juvenile cod.

They are sampling the fish with a beach seine and taking ocean water data aboard a semi-enclosed 22 foot skiff. To stay warm they wear insulated paddling suits.

Litzow and Abookire are collaborating with scientists at the Hatfield Marine Science Center in Newport, Ore., who have been studying juvenile cod in Kodiak over the last 12 years. The pilot study is funded by the Ocean Phoenix Fund through the University of Alaska Foundation.

Read the full story at Alaska Native News