Dakota Digest

Kuparuk’s Greyling Sound a Warning
Air Date: 10/29/2009

Fish on Alaskan stream struggle against a changing climate.

By Charles Michael Ray

24 years ago Linda Deegan came to the North Slope of Alaska and fell in love, with a fish.

"I must have cast 100 times to this one fish in this one pool slurping things off the surface and  I couldn't get my fly there for the life of me," says Degan "Until finally I landed this one just right and he kind of saddled over and took my fly." 

It was Deegan's first time fly fishing; she had just finished her PhD and went to Alaska to study the arctic grayling.  It's a cold water fish that is related to the rainbow trout.  And as far as fish go, grayling are easy to fall for.

"They're iridescent purple on the side with this gorgeous long sail fin that has multiple colors a little pink orange edge to it.  To me it's just a beautiful form of fish,"  she says. 

After that first catch with the fly rod Deegan was well, hooked.  She's spent every summer since 1985 in northern Alaska, studying the ecosystem on the Kuparak River.   Each summer day Degan and her research team slog across the wet tundra through swarms of mosquitoes to the banks of the Kuparak River.  The team spends a good part of its time catching and counting grayling; it's Bruce Pererson's favorite part of the job.   Today he's using a fly rod to catch and tag greyling.

"You see him?" Peterson points with his long fishing rod across the stream and the water ripples where a greyling pops up  to slurp a mosquito off the surface.  Peterson sinkers like a little kid about to make his first catch and says  "Watch this."   He casts the fly with expert precision and it lands right upstream from the fish's nose.   Peterson reels in a large grayling, "That's a nice one," he says "this is a beauty!"

Peterson is a senior research scientist, who works alongside Deegan at the Marine Biological Labratory in Woods Hole, Massachusetts. He has spent the better part of his career studying climate change.  Each fish he catches today will receive an electronic tag that will track its movement. 

"We'll be able to keep tabs on where they are where they're going,"  he says.  "We'll have a lot more information about the habitat usage by the fish."

The grayling the researchers have tagged tell an interesting story about climate change.  These fish migrate seasonally, each fall they swim upstream into deep headwater lakes, where they hold out for the long winter.  And over the last decade Linda Deegan has seen a drastic decline in the fish population on this stream,  a decline that is the result of something not at all common in this part of Alaska--drought. 

"And what we've documented is when we get these droughts they usually happen in the fall and that's when the fish have to move up to the headwater lake and they can't get there because the river is dry,"  Degan says.   "If they get trapped in this lower section of the river, the river freezes and they're stuck and they die."  

In 1999 Deegan and her team trapped and counted about 23-hundred Grayling during the fall migration, a decade later that number has dwindled to 331 fish.  She says the decline is due largely to summer and fall drought.  But she adds that in spring time the ice is now melting off the lakes sooner so the greyling are running downstream sooner; trouble is they're getting out before the mosquitoes hatch, so there is little for them to eat.   Greyling are also very heat sensitive and don't like the hot summer days.  The changing climate affecting this part of Alaska is a warning for what a warmer earth could bring to other parts of North America.  Deegan says the plight of the grayling on this river should be a red flag for the lower 48.

"I think they do provide a sort of a model organism for other fish in other streams - because we know a lot about them," she says. "We see the effects of climate change quite quickly and that allows us to say look if this is happening here what could be happening in the lower 48?"  "Maybe it won't be for another 10, 20 maybe 50 years, but it's coming."

Next summer Deegan and her team will be back to see how many of those last 300 or so grayling survived the winter.  It may be too late to save this fish on the Kuparuk.  But the researchers here hope that highlighting what climate change is doing in Alaska will help spur efforts to curb its potential impact in other parts of the world.