Mother Earth Journal

UBC Professor David Close. Courtesy University of British Columbia.

The Pacific lamprey is the most ancient of the native fish in the Pacific Northwest. This eel-like fish, which evolved more than 500 million years ago plays an integral part in the cultures of the Columbia River tribes.

But their numbers are spiraling downward.

Now, a University of British Columbia professor and member of one of the Columbia River’s treaty fishing tribes has discovered an ancient stress hormone that could help with lamprey conservation efforts.

As a clinical indicator of stress, the corticosteroid hormone is important for monitoring environmental impacts causing stress on the lamprey.

“If the Pacific lamprey are stressed because they are going down the river in barges or because they are trying to negotiate fish ladders designed for salmonids, we can now monitor that stress using this finding,” principal investigator and lead author David Close, an assistant professor in the UBC Department of Zoology told reporters.

Not only do his findings have a practical application in efforts to save the Pacific lamprey in the Columbia River, where the clinical monitoring of stress hormones in salmonids has aided conservation efforts for decades, they have also aroused the interest of the international scientific community.

“This new discovery is a significant contribution for understanding the evolution of the stress hormone signaling pathway in vertebrates,” said Close. “In addition, there is now a practical tool to monitor stress in these ancient fish, whether working on sea lamprey control or Pacific lamprey conservation.”

He published his findings in the Proceedings of National Academy of Sciences Early Edition in July.

He began his career in the fisheries program at the Confederated Tribes of Umatilla Indian Reservation in Northeastern Oregon. A Cayuse enrolled in the Umatilla Tribes, he published oral histories of tribal elders, who helped him to understand the biology of the Pacific lamprey and who charted its decline starting in the 1970s.

Like other lamprey, the Pacific lamprey has been historically viewed as a pest rather than a culturally important subsistence and medicinal fish it is to the Umatilla and other tribes on the Columbia River. The Pacific lamprey is native to the Pacific Coast from Baja California, Mexico, to the Pacific Northwest of the U.S., and to Japan. Like salmon, it is born in the freshwater,

Mouth of Pacific lamprey. Courtesy University of British Columbia.

travels to the ocean for its adult life, and then returns to the upper reaches of rivers where it forgoes food for a year before spawning.

Before construction of the dams, the Pacific lamprey were abundant and tribal peoples fished for them in the falls along the Columbia and its tributaries. But now there are only an estimated 11,000 Pacific lampreys left in the Columbia River, Close said.

The Umatilla have been at the forefront of calling for restoration of the Pacific lamprey, but have not been able to get the fish, which has no commercial fishery, targeted for conservation in the way that salmonoid populations in Washington, Oregon and California rivers. Many of the salmonid populations are listed as endangered or threatened under the Endangered Species Act.

The lack of information about the Pacific lamprey, which Close calls “living fossils,” has contributed to the lack of U.S. federal and state efforts to protect them. It took the Pacific lamprey’s cousin, the sea lamprey, to make this research possible.

“We needed to get a lot of blood to isolate the steroids, and we couldn’t use the Pacific lamprey because we didn’t want to kill this delicate population,” Close said. “We used the sea lamprey which is very abundant in the Great lakes as a model for Pacific lamprey which are located on the West Coast.”

The findings are important not only for the conservation of the Pacific lamprey, but also for the control of the sea lamprey. An exotic fish in the Great Lakes, it is blamed for decimating the fish population.

The implications of these findings are significant to the study of the evolution of stress hormones and their receptors. The lamprey as one of the oldest living vertebrates has a single corticosteroid and a single receptor for that hormone, while more modern vertebrates including humans have two corticosteroids and receptors which function to balance ions and the stress response.

“Through evolution, eventually these ancestral functions for responding to stress and ion balance diverged after a genome duplication event that produced two corticosteroid receptors,” Close said. “That’s how we think complexity in organisms has increased through time. When these functions diverged it allowed vertebrates to exploit more diverse habitats. It is about the co-evolution of steroids and receptors and eventual divergence of ancestral functions.”

For Close, the findings also indicate the importance of indigenous knowledge to science. He considers traditional knowledge to be just as important as western science to the management of tribal resources.

Close directs the University of British Columbia’s Aboriginal Fisheries Research Unit, dedicated to training indigenous students to conduct cutting edge research of importance to indigenous communities in North America. The unit currently has two aboriginal students from Canada, and is seeking to recruit more First Nations and Native American students from Canada and the U.S.

“By getting more Native peoples into the sciences with masters’ degrees and doctorates we can work through the political tool of self determination to protect our tribal resources,” Close told reporters. “Most of the time we have been hiring people to come in and do this science for us. They can miss important insights into natural processes that are known to our cultures, because of their cultural biases.”

Mother Earth Journal is a news project of environmental journalist Terri Hansen. Why don’t you follow Terri on Twitter? She’s on Facebook too.