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Arctic Fish a Sentinel of Climate Change
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Here in Connecticut public officials are debating the best way to implement a regional greenhouse gas cap and trade system. But thousands of miles away, on the north slope of Alaska, climate change is occurring more rapidly than just about any other place on earth. WNPR’s Nancy Cohen reports on an Arctic fish that could be a sentinel of climate change.

The Kuparuk River on the north slope of Alaska twists and turns, unhindered by roads or dams: Photo by Nancy Eve CohenThe Kuparuk River on the north slope of Alaska twists and turns, unhindered by roads or dams: Photo by Nancy Eve Cohen The Kuparuk River in the Arctic flows more freely than its northeastern cousins. It twists and turns without roads or towns to straighten its course and no dams to halt its flow. The Kuparuk’s pristine state is why aquatic ecologist Linda Deegan from the Marine Biological Lab in Woods Hole, Massachusetts came here 24 years ago to study its ecosystem and its fish.

“There’s an adult sitting right over there in that section. There. I sorta heard the “slurp” that it took when it was feeding on the insects flying along the on the surface there.”

“You can hear fish slurp?”

“I can hear fish slurp!”

Deegan is very familiar with the feeding habits of the Arctic grayling.
She has led a long-term study on the impact of environmental change on the fish. Over the years she’s caught and tagged about five thousand of them. Her method of choice: fly-fishing.

Aquatic ecologist Linda Deegan of the Marine Biological Lab flyfishing for Arctic Grayling on the Kuparuk River: photo by Nancy Eve CohenAquatic ecologist Linda Deegan of the Marine Biological Lab flyfishing for Arctic Grayling on the Kuparuk River: photo by Nancy Eve Cohen Standing thigh-deep in chilly water, Deegan sends her line singing above the surface. She uses a small lure that looks just like the mayfly the grayling feed on, but with a barb-less hook.

“If what I’m trying to do is measure what’s happening out in the environment I don’t want the technique that I use to catch them to affect their growth or their behavior... And because it’s so non-invasive it allows me to get really good data on what their growth and population size is.”

“Hey we got one.... Let’s see if we can get him into the shore here.”

Arctic grayling have been known to get as big as 23 inches long. This one looks to be just old enough to begin spawning—about 11 or 12 inches. Deegan will tag and release it.

“Whew! Here we go. First one of the season. Nice looking!"

Aquatic ecologist Linda Deegan of the Marine Biological Lab measures an Arctic Grayling: Photo by Nancy Eve CohenAquatic ecologist Linda Deegan of the Marine Biological Lab measures an Arctic Grayling: Photo by Nancy Eve Cohen

With its iridescent purple spots and a large dorsal fin many say the grayling is the prettiest fish in the Arctic. It has evolved to live in the cold. When the fall comes, before the Kuparuk River freezes solid, the fish migrate upstream to the headwater lake. But last summer in some parts of the river there wasn’t enough water for them to swim in.

“I’ve been working here 24 years now. In the first 10 or 15 years I never saw the river like that, dry like that, with patches of dry river stream. We never saw that in the first 15 years that I worked here. In the last ten years we’ve seen it three times. So it seems to be occurring with more frequency.”

Aquatic ecologist Linda Deegan of the Marine Biological Lab holds an Arctic Grayling she caught on the Kuparuk River: Photo by Nancy Eve CohenAquatic ecologist Linda Deegan of the Marine Biological Lab holds an Arctic Grayling she caught on the Kuparuk River: Photo by Nancy Eve CohenDeegan says last year it was so dry the Kuparuk dropped to about 25% of its usual flow. On June 29th, a time of year when the river is usually full of water, a group of scientists who work with Deegan at the University of Alaska’s Toolik Field Station, hiked upstream to check out the river. Among them, was research assistant Elissa Schuett.

“We worked our way up the Kuparuk... and found a large pool that was filled with grayling that were pretty much dying... It was a pretty small pool and there were a lot of grayling. And so there was not much oxygen for them to breathe in.”

The fish were trapped. There was no water between the pool and the main channel. Stream ecologist Alex Huryn, from the University of Alabama Tuscaloosa was also there. He says the group was so moved by the dying fish they stepped out of their scientific roles and intervened.

“We knew that it was going to dry up and they were going to die. So we were taking them in buckets and putting them in the main channel. In hindsight we probably shouldn’t have been doing that because this is a population that’s being studied in order to get information on the long-term term dynamics of the grayling populations and how the populations respond to climate change and things like that. So we added a human artifact into it., but that’s the way it goes.”

These very human scientists had their fishing rods and tagging equipment with them. They caught and tagged about thirty fish. But they lost count of how many they saved.

“There were two or three people fishing. And they were just pulling them out as fast as we could get them off the hooks and weigh them. I mean literally there was just fish flying though the air as we were pulling them out.”
The Kuparuk River on the north slop of Alaska, with the Brooks Range in the distance: Photo by Nancy Eve CohenThe Kuparuk River on the north slop of Alaska, with the Brooks Range in the distance: Photo by Nancy Eve CohenThe summer continued, warm and dry. A month later Elissa Schuett returned to the pool to see if it had reconnected to the main stream of the Kuparuk River. But no such luck.

“The pool was just bone dry basically. And then we saw I think about thirty fish that were dead on the ground.”

That’s thirty fish in one location. The scientists were not able to observe the entire river. Now Linda Deegan is trying to figure out the bigger impact. Not only are low flows a problem for the fish , but warmer water. Grayling don’t feed or grow as well if the water is warm.

“Oh I’m very concerned about this population. You know we’ve had summers before where its been dry during the summer and they’ve been stuck in pools. But always in the fall, sometimes in middle September, but we’ve always had rains that raised the river high enough and they just bolt for over-wintering spots. As far as we know last year we never had those kinds of rains.”

Deegan says last year’s weather was consistent with the overall predictions made about global climate change. But it’s hard to say what else it means.

The Kuparuk River on the north slope of Alaska with a pipeline in the background: Photo by Nancy Eve CohenThe Kuparuk River on the north slope of Alaska with a pipeline in the background: Photo by Nancy Eve Cohen“Now whether this is just a decade anomaly? It’s hard to tell. To know whether or not you’re really seeing what we call a true climate change takes several decades of measurements. But you know we’ve been here thirty years now and that’s three decades. The first two didn’t look like this. The last decade has been, well... we’ve had more warmer drier summers in the last decade and so its consistent with what the predictions from the global climate change models say should be happening.”

Deegan says the models say climate change will come sooner to the Arctic. But the changes won’t be confined to the north.

“If we’re seeing these things happening now in the Arctic --- and a lot of these changes are happening faster than the models ever predicted they would --- I think people need to take that as a signal that we are changing the climate, we are changing the earth and this is just going to march southward down to where they are.”

If climate change makes things just a little bit warmer and a little bit drier---it could make the difference between life and death for the Arctic grayling. A fish some consider a sentinel of change.

WNPR’s Nancy Cohen just returned from a science writer’s fellowship in the Arctic that was funded by the National Science Foundation and sponsored by the Marine Biological Lab. Linda Deegan is a scientist with the MBL.