Hometown U: Portage Valley a prime habitat for troubled chinook

Hometown UDecember 29, 2012 

The news on salmon in upper Cook Inlet is bleak.

According to Alaska Department of Fish and Game estimates, the coho harvest in 2012 was 45 percent lower than the past 10-year average. The numbers get worse for Alaska's signature fish, chinook, or kings. Their harvest in 2012 was 85 percent less than the past 50-year average.

Numbers like these raise the prospect that this Cook Inlet fishery, with an estimated economic impact in 2007 of $100 million and employing 1,000 people, might experience a salmon crash like those witnessed in the Pacific Northwest.

Luckily, there is a ray of hope. Portage Valley in upper Cook Inlet is framed with glaciers and they tend to create stable habitat well suited for overwintering juvenile salmon. This should make those area drainages a potential nursery for young fish, an important fact in light of the recent precipitous declines.

U.S. Forest Service fisheries biologist Mark Chilcote, UAA biology professor Douglas Causey and three of his students went hunting for young salmon in Portage Valley creeks and ponds. They made three sampling trips in October and November, checking six sites in the Placer and Portage River drainages. Using salmon eggs in minnow traps, their biggest news came Nov. 4 at the North Fork Williwaw Pond, a restored gravel-mining site fed by groundwater.

"On the students' second trip out," Chilcote said, "they found juvenile chinook," capturing 33 chinook, two coho and 13 Dolly Varden. "This is the first documentation of chinook in this area."

Chilcote was excited enough to share the team's findings with Alaska Department of Fish and Game biologist Dan Bosch.

"This is great news," Bosch responded by email. "I have always suspected that kings were in Portage Valley but this looks like the first documentation. ... Rearing of both coho and chinook at the end of Turnagain Arm is very complex, with fish spawning in one location and juveniles moving to other streams to rear."

That complexity was just what the UAA students were looking for -- and found. They hypothesized that the juvenile salmon would behave as efficiently as possible, locating near groundwater sources with raised temperatures and in pools and lakes with slow-moving water near structures. That's exactly what they found.

The three, Maio Nishkian, Kalie Dickey and John Flanagan, worked as a team, setting traps for up to two to three hours. When they captured fish, they anesthetized them for ease in handling, identified them and measured their length. After reviving the juveniles in a bucket of fresh water, they released them back to the stream.

This required an ADF&G permit issued to Causey for scientific/educational purposes. The students compared their findings with results from two BLM surveys done by interns in 1976 and 1977. Those surveys failed to identify any chinook juveniles in the area, though they found coho, stickleback and Dolly Varden.

In a later report to the class and field scientists from the ADF&G and the U.S. Forest Service, students commented with amazement on how old the previous survey data was. "Sampling has not been done for our entire lifetimes," noted Nishkian, a detail that greeted with laughter from students and professionals.

Terri Marceron, forest supervisor for Chugach National Forest, listened in the audience. In the Q and A that followed, she commented on how difficult it can be to manage the forest with such outdated data and how welcome the students' fresh numbers are.

Their work was done as part of Causey's new Exploration Ecology course offered this fall. The course paired UAA students with field biologists to conduct research on public land in partnership with the U.S. Forest Service.

"I wanted to give students the opportunity to develop research projects that had real impact on what we know about the Alaska environment and they certainly succeeded," Causey said. Several of the students will continue this work during the spring semester.

Chilcote, with the U.S. Forest Service, was their mentor and guide.

New to Alaska by just 18 months, Chilcote has spent 35 years in fisheries, many of them as an endangered species specialist in Oregon and Washington documenting salmon declines in the Columbia River basin. He witnessed their drop to single digits, noting that the least productive streams got to zero fish while major streams still seemed to be coasting along safely.

"Then," rather suddenly, he said, "fish just disappeared, a little population winking out."

Changes in how fisheries and hatcheries are managed has helped to start bring them back but Chilcote is mindful of the important role minor streams might play in the overall health of a species.

To him, Alaska presents nearly pristine habitat and a remarkable window in which to observe the evolutionary impacts of climate change on the existing species.

"Big changes will happen rapidly," he says. "We're in a 50- to 100-year transition right now. Survivors must adapt quickly."

Finding juvenile chinook where they haven't been documented before could mean the fish are expanding their range and even managing adaptation. Having lots of healthy young fish enhances diversity and increases the potential for evolutionary success.

"That little creek you think is not so important might end up being critical for the species," Chilcote said. "All the pieces combine to make the right habitat."

 

 

 


Kathleen McCoy is an electronic media specialist at UAA, where she highlights campus life through social and online media.

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