A fish species given top protections by the Endangered Species Act for more than 20 years has been proposed for delisting.
The Modoc sucker, Catostomus microps, was classified endangered under the ESA in California in 1985. The state had previously classified the fish under its own endangered listing in 1980. When Modoc sucker were later discovered to inhabit Thomas Creek in Oregon’s Goose Lake drainage, Oregon’s populations became protected under the 1985 federal listing.
As part of the proposal and before Modoc sucker can have ESA protections altogether removed, a Species Action Plan is open for a 12-month review. Over the next year, a 60-day public comment period and peer review studies from scientists outside the USFWS will help determine the species’ fate, according to Laurie Sada, Klamath Falls field supervisor for U.S. Fish and Wildlife Service (USFWS).
The Oregon chub, found only in the Willamette River Basin, was proposed for delisting earlier this month. The Modoc sucker is the second fish species to be proposed for delisting from the ESA. Once the review period is over, there are three possible outcomes: The species remains endangered; the species is downlisted to threatened; or the species is delisted.
“Modoc sucker could be one of the first fish to be delisted for reasons other than extinction. This shows how the ESA can work when we work collaboratively with others,” Sada said.
Oregon and California USFWS offices, the California Department Fisheries and Wildlife, and forest agencies, such as the Fremont-Winema National Forest, have worked closely to reduce environmental threats to the fish over the past decade.
“I think it’s maybe a once in a career event that might happen and that’s pretty exciting,” said Nolan Banish, a fish biologist for the Klamath Falls USFWS.
A brief history
For years the small freshwater fish was believed to only inhabit Ash and Turner drainages of the Pit River Basin in Northern California. According to a 2009 USFWS five-year species review, biologists discovered the species existed in Oregon in 2001 after Oregon State University specimens mistakenly identified as Sacramento sucker were identified as Modoc sucker from Thomas Creek.
“It’s out there in a corner of the world where we don’t have a lot of fish biologists,” said Stewart Reid, a former fish biologist for the Klamath Falls USFWS.
Further research showed that Modoc and Sacramento sucker inhabit the same watersheds, but thrive in different aquatic environments.
The Modoc sucker was known to inhabit only 12.9 miles of habitat in seven streams within the California basins at the time of listing. Today, it inhabits an estimated 42.5 miles of habitat in 12 steams within the three basins, a new release said.
“The good news is, they are turning up in more places than we ever expected,” Reid said.
According to Banish, nighttime surveys of Thomas Creek revealed Modocs inhabit cool, shallow pools along a 15-mile stretch primarily surrounded by Fremont-Winema National Forest. Another survey revealed a small population in an unnamed arm of the creek. Banish attributed some of the species’ success to forest management, which reduced the number of roads contributing to sedimentation and modified grazing strategies by constructing riparian fencing and requiring off-stream watering for cattle.
Another simultaneous effort from the Lake County Umbrella Watershed Council has worked with private landowners to install three fish passages in artificial barriers. According to Marci Schreder, council project manager, two more are slated for completion before 2015.
“The passages are instrumental because fish now have access to migrate year-round,” she said.
According to Reid, habitat degradation wasn’t the only concern for Modoc sucker survival when it was listed more than two decades ago.
Some biologists believed interbreeding between Modoc and Sacramento sucker would lead to a new “hybrid” species and potentially eradicate both. Reid, through long-term observations, revealed the naturally co-occurring species and interbreeding is extremely rare.
Some DNA studies have shown small amounts of genetic mingling, but Reid believes those instances were adaptive strategies to maintain diversity. If the species were going to completely hybridize, they would have done so long ago, he said.
“Sometimes it’s good to get some genes from another `village,’ ” Reid said.
Other natural barriers such as size — Sacramento sucker can grow as large as two feet, while most Modocs are only inches long — and alternate spawning seasons have helped keep the species separate. According to Reid, mating colors between the species vary quite a bit: a pink blush blends down male Sacramento suckers, while a bright orange band spans down the sides of male Modocs.
Sada said Modoc suckers feed on algae, aquatic insects, and small crustaceans. Although they are not especially charismatic, the species is vital for aquatic and riparian food chains because they break things down, assist in stream cycle, and are food for raccoons and other mammals.
Important to food chain
“We care because they are an important part of the chain of whether the system is healthy, and whether it’s functioning as it should to support all of the animals in that watershed. They serve as indicators. If they are not doing well, then that stream is having problems for other species that are likely of interest to game fishermen,” Sada said.
Much of the land surrounding Ash and Turner basins in California is surrounded by federal land open to cattle graze by permit. According to Marty Yamagiwa, Modoc National Forest wildlife and fisheries program manager, a fair amount of Modocs’ success can be attributed to habitat improvements that were maintained by cattle owners.
“We worked with them to build fences to exclude livestock. It was up to them to maintain the fences and keep the cattle out of those areas,” Yamagiwa said. “We’ve taken a lot of steps to recover habitat.”
If the species is delisted, the critical habitat surrounding California creeks — no critical habitat was designated in Oregon because Modocs were not known to inhabit the state at the time of listing — will no longer be classified as critical.
“Our role from now on will be monitoring to make sure we continue to recover habitat,” Yamagiwa said.