Shocking! Electrofishing for Largescale Suckers on the Columbia River

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[Steven Sobieszczyk] You are watching and listening to the USGS Oregon Science Podcast for Tuesday, May 24, 2011.

In this episode we take to the water and accompany a USGS field crew as they collect largescale suckers (Catostomus macrocheilus) along the lower Columbia River. Using a boat equipped with specialized shocking equipment, researchers stun nearby fish, allowing them to be easily collected and examined. Join us, as we explore how native fish are used to determine the water quality and ecological health of our local rivers, only in this month’s episode of the Oregon Science Podcast.

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[Steven Sobieszczyk] Hello and welcome. I’m Steven Sobieszczyk. Today we’re going to highlight one of our most common and effective tools the USGS uses for collecting fish: electroshocking. Just as the name implies, specialized equipment is used to emit an electrical pulse into the water and stun nearby fish. Think of it as a “stun gun” but much less powerful. In fact, the boat-mounted unit used in this study runs on only 4 amps and 60 volts of direct current. This provides an immobilizing shock that is considered non-lethal and only stuns the fish for a brief period. Essentially, it gives the boat operator just enough time to turn around and the netter to collect the fish.

To help understand this collection technique better we decided to set out and observe it in action, up close. On May 5^th, we joined a crew of USGS researchers to see how fish are shocked, collected, and examined. Lucky for us, the USGS researchers were sampling over a 3-day period at three different locations along the lower Columbia River. We caught up with them on their second day in field at the boat launch in the town of St. Helens, Oregon, about 30 miles northwest of Portland.

The lead investigator, USGS fishery biologist Matt Mesa, sat down with us to help explain what they were doing. Matt, what are you doing here today?

[Matt Mesa] We’re here in St. Helens on the Columbia River. We’re using electrofishing, which is a technique that…we can inject electricity…a mild dosage of electricity…into the water that stuns fish so they float up to the surface so that we can net them. We’re using that technique, it’s a very common technique used throughout the world, and we’re using that technique to collect largescale suckers; which is our test animal of choice for evaluating contaminant levels in fish that live in this area. So we’ve been working in an area near Longview, at Columbia city, or St. Helens, here. Then we have a third site further up the Columbia River near Rooster Rock. Each place we’re collecting largescale suckers.

[Steven Sobieszczyk] Why are you looking at largescale suckers?

[Matt Mesa] The reason we’re looking at suckers is because, well, they are a very common fish in the Columbia River Basin. They’re relatively long-lived, so they can live to be, we think, 8, 9, 10-years old. So, a big fish like this might be an 8- or 9-year-old fish.  They spend a lot of their lives in the area where we are working. So, if we catch a fish we’re assuming that it’s very reflective of the chemicals and things in the area where it lives. So, that’s the reason we chose the largescale sucker. Plus, they’re not listed as endangered, they’re very common, and they’re easy to catch. So they’re a really good test animal to look at how contaminated these sites really are.

[Steven Sobieszczyk] How are you examining the fish?

[Matt Mesa] We’re going to be taking those fish and we’re going to be removing some tissues from them so we can evaluate the concentrations of contaminants they have in, for example, their livers. We’re specifically interested in flame retardant chemicals. There are various derivatives, or isoforms, of these. But, we’ll also be looking at PCB and all the common kinds of chemicals people read about in the paper.

[Steven Sobieszczyk] How are these chemicals affecting the fish?

[Matt Mesa] What the group is really looking at is whether there are any impacts to the health and the reproductive condition of the suckers. So there’s a whole group of folks looking at various indicators, but so far the data is still coming out. We don’t really know yet whether the concentrations of chemicals we are seeing have had any reproductive impacts.

To be continued…

[Steven Sobieszczyk] Now if we’ve piqued your interest concerning contaminants in our rivers and streams, including in aquatic wildlife such as fish. Stay tuned. Later this summer we’ll be putting out another video podcast where we characterize contaminants and habitats in the lower Columbia River.

As for electroshocking, that’s all we have for today’s show. Thank you so much for watching. If you want to learn more about electroshocking or other topics we discussed in today’s episode you can find them listed in our show transcripts. You can find them at our website: http://or.usgs.gov/podcasts. If our monthly podcast doesn’t feed your need for USGS-related news here in Oregon, you can follow us daily on Twitter at “USGS_OR.” As always, if you have any questions, comments, or even complaints about the USGS Oregon Science Podcast, please feel free to email us at oregonpodcast@usgs.gov. To hear more about other research the USGS is doing around the world, check out any one of our other USGS social media outlets at usgs.gov/socialmedia. There you can listen to other USGS podcasts, as well as find links to USGS on Twitter, Facebook, YouTube, and Flickr.

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This podcast is a product of the U.S. Geological Survey, Department of the Interior.

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