State May Declare Unique NorCal Fish Threatened
The California Fish and Game Commission may decide soon whether to add a freshwater fish found in just one Northern California lake to the state's list of Threatened species.
The Clear Lake hitch, Lavinia exilicauda chi, a member of the minnow family that can reach 13 inches in length, is found only in Clear Lake and its tributaries in Lake County. Once so abundant that it was a staple food called "chi" by the local Pomo Indians, the hitch was recommended for listing as Threatened in May by the state's Department of Fish and Wildlife due to the destruction of more than 90 percent of the fish's historical spawning habitat.
That recommendation came as the result of an October 2012 petition by the Center for Biological Diversity to list the fish. Representatives of the group say they'll be at the Fish and Game Commission's August 5 meeting in San Diego to press for full Endangered status for the hitch, based on low spawning numbers in the last few drought years.
"Practically, there's not a lot of difference between the threatened and endangered listing," CBD's Jeff Miller told the Lake County News. Miller, who wrote the 2012 petition seeking listing of the hitch, was optimistic that modest adjustments in water use could preserve much of the hitch's remaining habitat.
A subspecies of the somewhat more widespread Lavinia exicauda, which is itself restricted to streams in Central California, the Clear Lake hitch evolved in the relative isolation of the nearly 70 square mile Clear Lake and its tributary streams in Lake County. It's thought the hitch may first have migrated into Clear Lake by way of Cache Creek, which flows from the lake into the Sacramento River at Woodland.
However the hitch first got to Clear Lake, it soon evolved new adaptations reflecting its change in habitat from Central Valley streams to the lake, including larger eyes to see better in deeper waters, and longer "gill rakers" -- bony projections growing in the fish's gills that help filter out the hitch's preferred food, plankton.
The CBD petition includes a passage that sounds all too familiar when describing the hitch's 19th Century abundance in Clear Lake:
Hitch were once a staple food for the Pomo tribes living around Clear Lake. Schools of migrating adult Clear Lake hitch were once almost unimaginably abundant, and the fish annually clogged the lake's tributary streams during spawning runs... Longtime residents vividly recall vast numbers of spawning hitch in every tributary to Clear Lake and Native American tribal elders remember that one could "walk across Kelsey Creek on the backs of the chi"...
A century and a half of dams, water diversions for residential and agricultural use, and upstream logging have likely changed that forever. Where hitch once spawned in almost all of the lake's tributaries in spring, seeking out stretches of stream with calm, clear water, the fish now regularly spawn in just two streams along the lake's south shore -- and then only in the lower reaches. And the lake's fringing wetlands, which provide crucial habitat for juvenile hitch, have been reduced as well, from about 9,000 acres in the 19th Century to less than 1,500 acres by the mid-1970s. Much of that converted wetland became farm fields, where irrigated crops then reduced stream water levels, further degrading the hitch's spawning habitat.
As a result, the Clear Lake hitch's numbers have apparently crashed. Though precise population numbers for the fish are unavailable, sampling data from deliberate surveys and reports of bycatch from commercial fishers show that the drought has really done a number on the hitch, with only a couple dozen fish counted in 2011 and 2012 as compared to 1,000 or so in 2005. The Department of Fish and Wildlife says 2013's numbers are likely lower than 2012's. Clear Lake hitch numbers have crashed before, indicating that the population can rebuild itself given a chance. But every such crash might well be the one from which the fish don't bounce back.
That thought is anathema to the Pomo, who view the hitch as a vital part of their culture and a link to their history. Though a limited tribal chi harvest continues, CBD's petition was supported by four local Pomo tribal governments, which have been enthusiastic advocates for keeping the hitch healthy.
The Clear Lake Tribes have been actively engaged in studying and protecting the Clear Lake hitch since 2005," said Anthony Jack, Tribal Chairman of the Big Valley Band of Pomo Indians, in a press release last year. "The Big Valley Band of Pomo Indians will continue to assist in protecting the few native species left in our region -- the benefits to the ecosystem will be felt by all."