Clearing (under) the road for juvenile fish

Dec 11, 2018

 

Maggie Harings (left) and Alice Main download data collected alongside Crooked Creek about fish passage.
Credit Shaylon Cochran/KDLL

To an early homesteader or, especially, native Alaskans before that, there’s been a whole lot of stuff built on the Kenai the past 70 or so years. And not all of it was done with an eye toward what would be best for both humans and wildlife habitat. But we’re learning.

 

 


 

Like any good cold-weather, scientific endeavor, this one starts with loading up a couple 100-pound propane tanks into a sled, and then chasing them down a hill next to a creekside test site.

 

Maggie Harings, an environmental scientist at the Kenai Watershed Forum and her co-worker Alice Main do this once a week. The propane provides power for the monitoring equipment they have set up next to Crooked Creek, just a stone’s throw away from Sterling Highway. They’re monitoring fish passage through this little section of creek with a pair of antennas situated in the water.

“This is one of four sites we have set up for (passive integrated transponder) tagging," Haring says. "We tagged 1,400 juvenile coho this fall. Those little guys are, theoretically, in the stream still, swimming around with tags in them. When they move within a section, if they happen to swim by one of these, they’re going to be picked up by one antenna and then the other. And each of them has a code associated with it and once they pass through an antenna, it gets registered with a reader, and we do weekly data downloads."

Getting a handle on how many fish populate this section of river is important because it’s clear some work needs to be done. A pair of small culverts under the highway has created a deep pool on one side of the road, making it more difficult for those coho and other species to make it upriver to spawning grounds.

 

Main runs the Watershed Forum’s Streamwatch Program, but today she’s working on other duties as assigned. Like wrangling those propane tanks.

“If you look down from the highway at these twin culverts, you’ll see that they’re perched, meaning that the water flowing out of them looks like a waterfall," she explains. "That’s what makes it difficult, especially for juvenile fish to go upstream. That’s part of the reason why you see that big pool, because the water is coming down and scoring out the bottom."

Plans are in the works to replace those culverts and that provides an opportunity to get some data and learn a little something.

“What we wanted to do was look at fish passage before the replacement, during and then after the replacement. Through this study, we’re also able to gain a little bit of insight into overwintering patterns and basically where the fish are in certain sections of the stream," Haring said.

This is more than just a simple counting exercise, like what you see daily out of Fish and Game for salmon counts in the summer. Because they’re zeroed in on specific sections, Haring says they can infer a lot based on how many fish are spending time in that section.

“So let’s say post-culvert replacement we’re finding a lot of fish upstream in this one stretch. Well, maybe we need to look into that further. What is so special about that stretch of river that is serving these fish so well."

And from there, a million other questions can pop up. But for now, establishing some baseline data is the focus to help give the fish a more clear path to where they need to go. Replacement of the culverts at this site is expected sometime next year.