Get ready to be borealized

Wait. The what of the who into where?

This sent me scrambling for my Webster’s. “Advection” is when something is carried along with a liquid, like silt in a flowing river. “Anomalous” just means freaky. And “biota” refers to living things. So borealization is the freaky flow of plants and animals into the arctic, carried along with waters coming up from the subarctic to the south.

Borealization has coincided with the near disappearance of the “cold pool,” a pool of cold bottom water associated with winter sea ice in the Bering Sea. In years past, the cold pool would follow the edge of the sea ice as it comes down each winter. The boundary between the cold pool and warmer subarctic waters is a significant one. For one thing, it keeps the cod out. Codfish don’t like the cooler waters, and they stay out of the cold pool. This is a lucky thing for young crab, whose favorite place to grow up is the nutrient rich waters on the cool side of the border. 

The cold pool provides more than a thermal wall that protects young crab from cod. It also provides a nice cool nursery for baby crabs on the bottom.

A scientific paper from December 2020 titled “Recent shifts in northern Bering Sea snow crab (Chionoecetes opilio) size, structure, and the potential role of climate-mediated range contraction” says, in part: “Dramatic declines in juvenile snow crab abundance observed in 2019 may be attributed to potential direct or indirect temperature effects on survival of highly stenothermic early benthic stages of snow crab.” Okay let’s get the dictionary out again…ah! “Benthic” means it lives on the bottom, and “stenothermic” refers to “a species or living organism only capable of living or surviving within a narrow temperature range.”

It turns out baby snow crabs are very sensitive to water temperature when they first settle down to the bottom as they transition from a free swimming larval state. Unlike cod, they prefer the cooler waters of the cold pool. And crab larvae love to feed on the extra nutritious plankton blooms that occur in the boundary between the warm and cold waters. Warmer conditions have thrown off the timing, location and composition of the plankton blooms that crab larvae eat. As a result, larvae could be skinnier when they do settle down to the bottom. Once there, they find the water is too warm, and that cod, uninhibited by cold water, are coming across in droves to feast on delicious baby crabs.  

There is evidence that adult crabs are marching north with the rest of the biota, and that a future crab fishery in say, the northern Bering Sea, might be possible. But there is little evidence yet of an emerging northern nursery that would supply new recruits to replenish that fishery.

One takeaway here is that borealization is not a smooth, orderly march to the north. It is more of a mad rush, as borders break down and the biota retreat northward into ever shrinking territory. There will be wars and skirmishes, and winners and losers, among the fleeing flora and fauna.

There is strong evidence of a human role in borealization. Rapid, human-caused climate change is seen as its primary driver. And it has been pointed out that for crashed stocks like Bering Sea snow crab the term “natural mortality” should probably be replaced by “non-fishing mortality.” We might not have crashed them by overfishing, but it must be admitted: We did it. There is every reason to expect warmer conditions to continue, and further borealization along with it.

And humans are not immune to its effects. As species move north, and the ice continues to melt, it’s easy to see an increasingly important role for the arctic as both a source of food, an international waterway, and ultimately, a place to live. Because a kind of borealization is surely in store for all of us.

When I first moved to Alaska from California over 30 years ago, I joked that I was going north ahead of the coming climate apocalypse.

That joke does not seem so funny anymore. Places like California and Australia are gigantic tinderboxes. Colorado aquifers are tapped out. Lake Mead is a puddle. The frequency and duration of droughts worldwide has increased by nearly a third since the year 2000. Worldwide, more than 2 billion people do not have enough water. Of the 10 warmest years ever recorded, nine of them were the past nine years.

Get ready to be borealized, folks.

Terry Haines was a commercial fisherman in Kodiak for more than 30 years. He now produces the Alaska Fisheries Report for KMXT and is a member of the Kodiak City Council. He can be reached at thaines@city.kodiak.ak.us