Fieldwork Fun: Day one — No Bull (Trout) Here

by Hallie Morris

The fish survey crew can be seen in Lucky Peak Reservoir, near Boise Idaho. Photo credit: BOR

School’s out for the summer! For many of us, that means lazy, hot days relaxing in the shade or adventurous travel, but this year, for me, it means embarking on a summer internship for the U.S. Fish and Wildlife Service (USFWS). I wasn’t really sure what to expect, except that my packing list included sunscreen, bug repellant, and chest waders (required). On my first day in the field, I was able to put all three of these things to good use!

There was no opportunity to sleep in, as the meet up time was 6:30 am, and this was especially harsh, coming from a more western time-zone. Day one of fieldwork was spent working with a partner agency — Bureau of Reclamation (BOR) — to locate, catch, and relocate bull trout. Bull trout are listed as threatened under the Endangered Species Act (ESA), and USFWS is charged with managed listed species. The BOR needs to monitor bull trout to determine the effects of their water management projects on the species. So, my fellow intern and I learned how to trap fish, utilizing gill nets. While gill nets can be dangerous to fish if left for a significant amount of time, when used carefully, they can be an expedient, effective method of finding fish in their natural habitat.

Four biologists stand in a parking lot, looking at the gill net that. They are all wearing chest waders.
A woman in a lifejacket sits on a boat, watching a bouy in the water.
The fish crew learns how a trap net works by opening it up in the parking lot and go over a data collection plan on the boat. Photo credit: BOR

Although most fishing excursions usually set out in hopes of catching fish, we were actually glad that we didn’t locate any bull trout that needed to be trapped and hauled to a different reservoir. Fish passage is not available at Arrowrock Dam so any bull trout caught in Lucky Peak Reservoir need to be transported above the dam in order to migrate and spawn in their natal streams. The lack of bull trout in this area likely means that BOR’s adaptive management of the project minimizes entrainment at Arrowrock Dam. We recorded the other fish we did capture: Large-scale suckers and bridge lip suckers were the most common species we pulled up. We also discovered a single white fish, a Northern Pike minnow, and a furious log that knotted the entire net. After we pulled in a net and recorded the fish, we gently released them back into the water.

An assortment of fish species were captured that day. They were held safely in a bucket and measured and recorded. Photo credit: BOR

The system we used was to have four nets going at a time and it worked like this: Set the first four on one side of the river, waited 30 minutes then went to collect the first net we set. Every time we pulled up a net, we set it somewhere else then went back to the second placed net and so on. We set and reset the nets for about four hours while the other intern and I switched between doing data or nets with the other biologists.

Hallie works to remove the fish from the net and carefully prevents injury. Photo credit: BOR

I expected to feel nervous about touching the fish to free them from the nets, but I surprised myself by not being bothered. They were soft on their sides and sharp and bony along their back. It was very cool to see them so up close and how they responded to us. Some of the fish were dubbed “drama queens”. Today, I learned about fish capture techniques and the reasons why we were doing it. More importantly, I learned about how the ESA not only inspires diverse partnerships to prevent species extinctions and recover listed species, it also supports proactive collaborations with states, private landowners, conservation groups and industry to conserve species.

Check back for the next adventure. Teaser: it involves a species smaller than a pencil eraser and in serious decline!



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USFWS Columbia Pacific Northwest Region

USFWS Columbia Pacific Northwest Region

Conservation stories from one of the world’s most ecologically diverse regions.