More sockeye are swimming up the lower Yakima River. That’s after heavy machinery removed an earthen landbridge in the Tri-Cities that blocked the river’s flow.

It’s been about six months since excavators scooped out the dirt and rock that made up the Bateman Island Causeway. The stagnant water behind the landbridge could get really hot in the summer. It also created space for predators to snack on salmon.

Now that the water is no longer blocked, biologists said they’ve seen an increase in sockeye salmon in the lower Yakima — nearly 400 sockeye as of today, said Zac Zacavish, a research biologist with the Yakama Nation.

He said it’s likely the highest percentage they’ve seen since the Yakama Nation first released sockeye for its reintroduction program in 2009. Biologists had predicted removing the causeway would be a ‘huge step’ for salmon in the Yakima River.

“ This is a really good return comparatively to the Columbia River return,” Zacavish said.

Sockeye fisheries on the Upper Columbia had to be canceled because of low sockeye numbers.

Biologists want sockeye to move quickly during the hot months of June and July. That’s when most of this sockeye run made it to the mouth of the Yakima River.

“Having that causeway out allows them to just queue in and boogie,” Zacavish said.

In addition, he said, a cool spell a couple of weeks ago helped cool water temperatures. So did the smoke, which decreases solar radiation.

Now, summer Chinook are moving into the Yakima River, Zacavish said.

A lot of salmon work is ongoing on the lower Yakima, he said. Along with the Bateman Island Causeway deconstruction, tribal, local and state partners have worked to remove stargrass. Larger projects are in the works as well, he said.

“The Lower Yakima River is a huge bottleneck for smolt survival and adults coming up with the thermal block that sets up. So a lot of effort over the last few years and into the future is going to actually be on the lower river projects,” he said.

And there’s more work to be done with the now free-flowing mouth of the Yakima, Zacavish said. Biologists are planning to study what routes young salmon are taking now, and how that compares to the routes they took before the causeway was removed.

Read the audio transcript here.

Courtney Flatt is a reporter with Northwest Public Broadcasting. This story comes to you from the Northwest News Network, a collaboration between public media organizations in Oregon and Washington.

It is part of OPB’s broader effort to ensure that everyone in our region has access to quality journalism that informs, entertains and enriches their lives. To learn more, visit our journalism partnerships page.

News Source : https://www.opb.org/article/2026/08/15/yakima-river-bateman-island-causeway-removed-sockeye-salmon-returning/