As scientists from around the state and country gathered to discuss Arctic shift last week, it became clear that more questions than conclusions are available about Arctic fish populations -- and where the warm winds of change will take them.
Sea ice is at a record low, ocean acidification is on the rise, an undulating Arctic weather system is pushing extreme weather around the globe, and marine life populations from algae blooms to polar bears are in major flux. Needless to say, there are a lot of variables to track. All of which can and are affecting fish populations throughout the Arctic.
That, perhaps, is one of the biggest challenges expressed by scientists at the Lowell Wakefield Fisheries Symposium, hosted in Anchorage last week by the University of Alaska Fairbanks's Alaska Sea Grant program.
The variables are significant and difficult to predict, and holes in available data and research coverage are posing a major challenge to those trying to do just that.
Some of those researchers are trying to answer another question important to Alaskans.
"Are there going to be commercial fisheries in the Arctic, and if so which species?" Anne Hollowed of the Alaska Fisheries Science Center posed the question during her talk about the movement of fish and shellfish from subarctic to Arctic waters. She noted that the potential for large stocks of marine life to shift north is a complex development that she's been watching closely.
And at this point, the answer seems to be -- not yet.
"The key here is to recognize that it's not just your bioclimatic window that determines where you're going to be," Hollowed said. "It's more complicated than that."
For a migration that significant, a species needs more than open water and warming temperatures, she said. The species must be able to be productive, must have a rapid growth rate and be able to thrive over short periods, must have access to spawning habitat, and access to a suitable prey base.
Of the species that are more likely to shift north, Hollowed listed polar cod, snow crab, Bering flounder, Greenland shark, Arctic skate and beaked redfish.
Leandra De Sousa, of the North Slope Borough Department of Wildlife Management, said from her own research and what was presented at the symposium, that while larger, commercially desirable marine life have been observed, the numbers aren't there for commercial harvest. And may never be.
It's important to note, De Sousa said, that this was a general conclusion many scientists have reached. That does not necessarily reflect the industry agenda or political intentions for fisheries changes in the Arctic.
"So far with the data that we have, there is not enough of a capacity for it to be sustained," De Sousa said. "But that's only a decision in the U.S. waters." The U.S. put a moratorium on commercial fishing the U.S. Arctic in 2009. "Perhaps the moratorium should be renewed for the U.S. waters until we can get more information," she said. "The 10 years are going to come up soon and perhaps they should extend that moratorium and extend dialogue with other countries."
Other side of the pond
George Hunt from the University of Washington pointed out that while the Pacific Arctic has been slow to see shifts of commercial magnitude, the same cannot be said of the Atlantic-fed Arctic.
Hunt was recently part of a team that studied the difference between the Barents and Chukchi Seas, two Arctic Shelf systems with vastly different fishery potential. Part of that has to do with the high shelf on the Pacific side. "Way over 50 percent of the Chukchi is less than 50 meters deep," Hunt said. "So it's a very shallow sea, and the Barents Sea, a lot of it is quite deep." This affects the flow of warm water into the Arctic, he said, and in the Barents Sea they often find relatively warm water at depth, thought to be a boost to the thriving fisheries there.
"Fisheries catches are huge in the Barents Sea," Hunt said. That fishery focuses on capelin and Atlantic cod. "So we've got a difference in temperature between the places. We've got differences in depths with deeper water having a possibility of a low area where you can find the equivalent of migrating to Florida. The other thing is a lot of the fish species or several of the fish species that hang out in the Barents come out of the Barents for some part of their life cycle. And that means they can spawn or forage in places that are nicer."
Studying the two shelf systems gives Arctic research a point of comparison in this arena, Hunt said, a useful system of analysis as fisheries science attempts to predict and prepare for changes in the north.
Franz Mueter made a similar point in his discussion of Arctic cod. He called the common Arctic fish an indicator of northern shifts, considering its vital niche in the food chain and distribution. "Arctic species with circumpolar distribution -- such as Arctic cod -- may serve as 'bellwethers' of climate change as their distribution in marginal seas contracts and expands," Mueter noted.