Can new studies make gulf fisheries more predictable?
What helps – or hurts – the health of Gulf of Alaska’s fisheries? More than 40 scientists from 11 institutions are searching for answers as part of a five-year study of the gulf’s vast ecosystem.
Among other things, they’re creating a baseline of data to help determine climate change’s impacts on fish growth and populations.
We paid a visit to one Juneau research facility to find out about its part of the study.
Ron Heintz opens a glass case in one of the laboratories where he and his team are studying groundfish.
“So the fish come in here and then we weigh them and we have to cut their stomach contents out and we’ll probably look at those to see what the contents were,” he says.
He pulls out a test tube holding what looks like a small amount of powdery dirt.
“They get dried and then ground into this powder here. … It’s just a dried pulverized fish.”
Heintz is a program manager for the Alaska Fisheries Science Center at NOAA Fisheries’ Ted Stevens Marine Research Institute.
His office overlooks Favorite Channel, an Inside Passage waterway about 15 miles northwest of downtown Juneau.
“What we’re interested in is how climate is influencing the survival of juvenile fish that contribute to these fisheries. So a fishery is conducted on rockfish or pollock or Pacific cod,” he says. “We need to know how the juveniles enter those populations, so we that can manage them more effectively.”
The focus here is on juvenile groundfish. In addition to pollock and cod, they’re also studying sablefish, Pacific Ocean perch and arrowtooth flounder.
Others are researching predators, factors affecting food and differences between the eastern and western gulf.
Information is being gathered at more than 200 locations along the ocean shelf from Southeast’s Baranof Island, north to Yakutat and west to the Kenai Peninsula and Kodiak Island.
“A lot of studies are very single species, single mechanism. This is a real attempt to understand how the ecosystem works as a whole,” says Phyllis Stabeno, an oceanographer at NOAA’s Pacific Marine Environmental Laboratory in Seattle.
She says this project is looking at several species and changing conditions, such as temperature, current and rainfall.
“The reason we’re looking at five species of fish is species interact. The system is very complex and we’re trying to understand the major drivers of what results in survival.”
Before they can be studied, the fish have to be caught.
Wyatt Fornier is a Juneau lab field chief who samples the sea. He says his crew first records temperature, zooplankton populations and other relevant information.
“And then we’ll put on a research trawl, which then we string with buoys along the headrope, which keeps it right at the surface. So we’re just looking for the little fish on this survey … our little guys in their first year at sea,” he says.
Once they’re brought back to the lab, Heintz and his crew run them through a series of tests.
“For the rockfish, it’s very difficult to tell the little babies apart. So we actually have to then send them off to do a genetic analysis, so we can identify what species we actually caught,” he says.
They’re checked for protein and fat content, plus other tests, using a variety of equipment.
“If the fish is doing really well and has lots of body fat, then we would think that the fish is in pretty good condition. And it’s probably not too concerned about lots of predators, it’s finding lots of food, it’s living in an optimal temperature, the currents are providing it with the things that it needs to have a happy life,” Heintz says. “If the fish is really lean and not putting on a lot of fat, then it’s probably suffering somehow.”
These and other tests, when combined with other parts of the study, give researchers a better idea of the health of groundfish stocks.
It’s information needed by scientists and fishery managers. But why should everybody else care?
“Because most Alaskans like to eat fish. And our job is to provide those fish and to make sure that those fish are available for your kids to eat and your kids’ kids to eat. This is the only way we know how to do it, is to make sure we don’t overfish the stock, by understanding how the ecosystem works,” Heintz says.
The Gulf of Alaska study is scheduled to continue through 2014. It’s funded by the North Pacific Research Board.
In addition to immediate information, what’s discovered will give future researchers a well-documented reference point.