PNW Could Become 'Shad Nation'
by Amanda Arden
Scientists say more research needs to be done on how shad are impacting native fish
PORTLAND, Ore. -- In the last 20 to 30 years, shad populations in the Columbia River have soared while salmon populations dropped significantly. This contrast between one fish species thriving and another suffering led the Northwest Power and Conservation Council to wonder if shad were contributing to the fall of the salmon.
The Northwest Power and Conservation Council is meant to balance the environment and energy needs in Oregon, Washington, Idaho and Montana and has been monitoring the shad, steelhead and salmon populations in the Columbia River for decades.
The council says non-native shad are now the predominant ocean-migrating fish of the Columbia River Basin, with its numbers dwarfing those of native steelhead and salmon.
That's what led them to ask: Are shad having an impact on salmon and on the Columbia Basin ecosystem?
The council asked the Independent Science Advisory Board to look at the numbers and make recommendations for improving research and management of shad populations in the river. Before this, not much research throughout the Northwest had been targeted at shad and the species' potential impact on the environment.
The board published a report October 22, 2021, but concluded that more research needs to be done to determine if shad present direct risks to impacting salmonids. The report said that large numbers of the non-native shad could indicate long-term effects, but those effects remain to be discovered.
The board pulled its numbers from outside sources and did not collect any new data of its own for the report it published.
So, the question still remains: why are shad thriving while salmon are suffering?
Dr. John Epifanio, one of the researchers from the Independent Science Advisory Board, said some of the environmental impacts that could be harming the salmon could be the reasons shad are proliferating.
"There's probably not a direct link with the salmon declines that are caused by the shad," he said. "It appears to be a couple of conditions, changes in the flow through the system, changes in the temperature that a slower water move is related to and then ocean conditions."
Epifanio said the warming temperature of the ocean appears to be favorable for shad. The study said that these changing environmental conditions will likely continue to contribute to further decline of native species and will be favorable to non-native species, like shad.
Shad populations also increased abruptly after The Dalles Dam was completed in 1957. The dam's completion flooded Celilo Falls, which was previously a barrier to the upstream migration of shad. ISAB says since 1960, shad have increased at about a rate of 5% per year with no evidence showing the population growth is slowing or leveling off.
American shad are a member of the herring family and were introduced in the Columbia River in the 1870s and 1880s because of the fish's popularity in the eastern United States.
However, the fish is bony and oily, and it never gained popularity in the West.
The fish also has no significance to Columbia River Basin tribes. Dr. Zach Penney, the Fishery Science Department Manager with the Columbia River Inter-Tribal Fish Commission, said tribes in the region are concerned about the negative impacts shad could have on native fish populations.
"I don't really want to villainize shad just yet. That's another thing to keep in mind about invasive fish. It's not like they're, you know, having a maniacal laugh once they're getting to a place they don't exist. They're just doing what shad do," he said.
Penney said more studies need to focus on what's going on with the populations in the Columbia River in case it does become a bigger problem.
He also feels the populations need to be managed better in some way. Right now, there's no limit on the number of shad fishers can catch in the Columbia River and they can be fished for all year in most areas.
Since the fish are so boney, Penney said not many people catch them and eat them. He said they're good smoked and canned, so the bones soften, but otherwise they aren't very desirable. He said some people use them as bait for other fish and some have attempted to market shad, but he hasn't heard of there being enough demand to keep it going.
"So right now, shad in, I'd say, the Columbia River is primarily a recreational fishery. When it comes to tribal fisheries, shad primarily exists as by-catch," he said. "Shad are just accidentally usually caught in the nets and actually some fishermen get really irritated with them because they're a little spiky."
Penney said tribes from the Columbia River region are "People of salmon, not people of shad."
While shad are multiplying rapidly in the Columbia River, ISAB researchers found that the populations aren't doing as well in their native East Coast waterways. Their abundance has plummeted dramatically since the 1950s. Researchers say this is due to blockages, such as dams, that prevent them from swimming upstream to their native spawning sites.
Overall, researchers stress that more research must be done, especially if shad populations continue to rise without showing signs of plateauing in the Columbia River. They said it's essential shad numbers continue to be monitored and suggest more research on how shad impact certain habitats and compete for resources with native fish.
"I would hate to see the Pacific Northwest become ‘Shad Nation' instead of ‘Salmon Nation,'" Epifanio said.
Watch Largest West Coast Bass Fishing Tour to Show Off Columbia River and Tri-Cities in June by Wendy Culverwell, Tri-City Herald, 6/4/16
Unlike salmon and steelhead, shad are not native to the Columbia. by Staff, Northwest Power & Conservation Council
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