Biologists are hoping a new underwater monitoring system installed in the Link River will give them insight into how endangered suckers are using the 1.5-mile-long waterway.
In early December, crews will install 240 feet of 4-inch polyethylene pipe containing a passive integrated transponder (PIT) detection system. The small electronic PIT tags are inserted in a fish’s belly, and the array detects the fish as it passes over in-stream sensors.
The tags assign fish a unique identifying number, allowing biologists to monitor its growth, survival and movement.
According to Darrick Weissenfluh, lead fish biologist for the U.S. Fish and Wildlife Service Klamath Falls office, the array will be installed near the mouth of the Link River, just upstream from a natural reef where the water is shallow.
Weissenfluh said two rows of 12 pipes, made up of 20-foot sections, will be fastened to the reef with concrete anchor bolts and ratchet straps. The semi-permanent array could be used for the next 10 years.
“It really depends on what information we get,” Weissenfluh said. “We need to better understand sucker movements up and down the Link River and through the Link River Dam.”
Few fish using fish ladder
Lost River and shortnose suckers were listed under the Endangered Species Act in 1988. Both species have suffered from fish die-offs and poor survival rates in recent history.
Weissenfluh said scientists have tagged roughly 30,000 Lost River and shortnose suckers. Scientists believe 1,000 to 2,000 untagged adult suckers live in Lake Ewauna. The Link River Dam already has a fish ladder that allows suckers to move upstream into Upper Klamath Lake. A PIT detection system installed on the ladder has revealed few suckers are moving between the Link River and Upper Klamath Lake.
“Annually, usually less than 20 suckers are using the fish ladder,” he said. “We don’t really know why.”
It’s possible Lake Ewauna suckers are not moving north into Upper Klamath Lake and spawning grounds in the Williamson and Sprague rivers because they are spawning in Link River, but no surveys researching that have been done yet.
“Are there a substantial number of fish moving upstream past this first reef, but not getting to the fish ladder either because they can’t or because they are choosing to spawn in the Link River?” Weissenfluh asked.
Solar-powered tracker
USFWS is working with the Bureau of Reclamation and PacifiCorp to reduce flows in the Link River, down to approximately 300 cubic feet per second during the week of installation.
“It will almost completely expose the natural reef so we can walk on top of it,” Weissenfluh said.
The Idaho-based company Biomark has been contracted to design, fabricate and install the array.
“They’ve looked at this site and think it will be one of the more challenging installations they’ve done,” Weissenfluh said.
Two Biomark contractors will install the array with the help of about 10 representatives from state, federal and tribal stakeholder groups. The system will be solely run by energy generated with solar power panels set up on city property adjacent to the river.
Weissenfluh noted that in addition to the array, the system’s electronics, cable and conduit will also run underwater until it reaches the property where the solar panels are installed. The $109,500 project is being funding by the Klamath Falls U.S. Fish and Wildlife Service.