A commercial fisherman working on the Columbia River, near the mouth of the Yakima River, may have netted a 24- and a 36-inch gar, according to the Washington Department of Fish and Wildlife.
The fish, caught April 14, may have been alligator gar or perhaps shortnose gar, WDFW district fish biologist Paul Hoffarth said.
"I got an email last Tuesday morning with a video. I called back immediately, hoping he still had them in his possession," Hoffarth said. Unfortunately, the fisherman had released them after taking the video, as his permit didn't allow him to keep other species.
Gar are not native to the Columbia River, and both the alligator and shortnose varieties are predatory fish, so they would likely prey on salmon, steelhead and other native fish. "I'm sure these are like most fish species. If they can get it in their mouth, they can eat it," Hoffarth said.
And gar grow large enough—alligator gar up to 9 feet long—that they could easily eat very large salmon, he said.
Hoffarth said the issue is more concerning because there are at least two out there. "We're definitely going to follow up and make sure we don't have a problem," he said. "A couple of isolated fish is probably not a huge issue, but a population is a concern."
He said two experts have identified them as alligator gar, which are native to southern states in portions of the Missouri and Mississippi rivers. Populations of shortnose gar are found in the Missouri River as far north as Montana.
"The closest populations are so far away, it's really unlikely somebody would go grab them from the Missouri to turn them loose in the Columbia River," Hoffarth said. A more likely scenario is that someone kept them as pets in an aquarium or pond and decided to set them free—which is illegal, he noted.
The good news is that gar are not adapted to the Columbia River habitat, and if they're alligator gar, they're used to much warmer water, he noted. Biologists have tried a couple of times to capture them, but so far they haven't been recovered. "Our commercial carp fisherman is going to be back out, and he's now been permitted to hang on to them and hand them over," he added.