The Central Valley is the only place on Earth with four distinct runs of Chinook salmon (fall, late-fall, winter, and spring). Each run was adapted for different conditions and had multiple independent populations that spawned in different valley tributaries. The damming of virtually every Sacramento and San Joaquin tributary resulted in catastrophic losses of spawning habitat…100% of winter run, 90% of spring run, and 60% of fall run (the only run that relies primarily on the valley floor) spawning habitat is above dams. The pre-dam, Central Valley “diversified portfolio” of runs reached upwards of 2 million spawning fish per year.
From 2009 thru 2013, total returns for all four runs combined ranged between 70,000 and 150,000 fish—only 5% to 7.5% of average historical abundance. Today, the winter and spring runs are listed under the Endangered Species Act (in 1990 and 1998, respectively), and the late-fall run is small and in decline. In recent decades most salmon returning to the Central Valley have been fall-run fish and are overwhelmingly (estimates as high as 90% in some years) of hatchery origin.
The decline of California’s wild, fall-run Chinook salmon populations has been driven by dams, loss of floodplain rearing habitat, and a Sacramento-San Joaquin Delta in steep decline. But, it’s also important to recognize that the plummet in wild fish populations has been both obscured and exacerbated by massive hatchery production. Although they may look similar to wild fish, hatchery salmon are, in a very real sense, domestic animals bred for hatchery conditions, but sadly unfit for survival in rivers.
Currently, a mix of five state and federal operated Central Valley hatcheries, release more than 30 million Chinook smolt each year irrespective of the adult return rate of hatchery fish. And, while hatchery production is at an all-time high the number of wild spawners and commercial fisheries yields have plummeted to all-time lows.
Practices like trucking salmon from hatcheries to estuaries, increase the likelihood that adult fish will not return to the hatchery where they were born, but rather stray, often spawning in other rivers where they interbreed with wild fish. It is not uncommon to find fish born at Feather River Hatchery spawning in the American or Mokelumne River, and so on. The past 60 years of Central Valley hatchery production have resulted in replacement of multiple natural populations adapted specifically to the unique conditions of their home rivers with a single “lowest common denominator” hatchery population, thereby greatly increasing extinction risk.
Endangered salmon populations greatly complicate delivery of water to human needs like agriculture and drinking water. The tens of millions of dollars spent annually to produce salmon in inland hatcheries are dwarfed by the hundreds of millions spent to deal with the environmental, regulatory and legal consequences of having produced those same fish. What one hand gives, the other takes away: the publically funded fish hatcheries undermine the publically funded wild salmon recovery efforts. This piecemeal approach to fisheries resource management is not economically viable. Nor is this strategy viable for avoiding extinction.
In the long term we can better manage salmon to have both more fish caught in our commercial and sport fisheries and to recover self-sustaining wild populations in the Central Valley. Given the impacts of the current drought on river fish habitat such as low flows and unfavorable water temperatures (not to mention an increased risk of predation), we can understand the desire for a short-term measure like trucking which can increase ocean catch. But, in the long run, to put California salmon back on California tables and revitalize fisheries, while simultaneously recovering wild populations, we must move away from the obsolete, counterproductive hatchery practices that have put us on our current spiral towards extinction of both salmon and salmon fisherman in California.
We’re in agreement with our partners at the UC Davis Center for Watershed Sciences that a comprehensive re-thinking of hatchery management must be undertaken in California. Ideas to consider include …
1) Geographically isolating wild fish from hatchery fish by relocating hatcheries downstream, closer to estuaries. This will improve smolt survival, resulting in increased catch of hatchery fish in ocean fisheries while simultaneously reducing interbreeding between wild and hatchery fish in rivers. Some success with this approach has been seen in other states.
2) Protect wild fish genetic stock by requiring hatcheries to use broodstock with life history characteristics like migratory timing that would minimize dilution of wild California gene pools.
Trucking may help for a year or two in a time of dire drought emergency but if California is to ever revive a consistent and thriving commercial and recreational fishery and resilient populations of wild salmon it will require new thinking about hatchery practices.