Salmon run will collapse unless we reverse underlying causes of decline

The short history of decline of west coast salmon, and the steps we should take to consider recovery.

"It is a matter of serious regret that our choicest and most valued fish, the ... salmon, is annually decreasing and the supply for exportation and home consumption is diminishing. Unless salmon that now home in our waters are protected and fostered as a nucleus for increase, our rivers will become barren of this most desired fish."

These words appear in an 1886 report of the Commissioners of Fisheries of the State of California, but they could have been written yesterday. While some suggest the current collapse of the Sacramento chinook salmon run is unprecedented, we are poised to repeat unlearned lessons from a century ago unless conservation measures are enacted that reverse the underlying causes of the salmon decline.

Salmon harvesting in California began in the mid-1850s as an inland fishery, was stimulated by the canning industry, and soon met a fate similar to the infamous Cannery Row sardines. The first salmon cannery opened on the Sacramento River in 1864 near Broderick. By 1881, there were 20, but by 1885, only six canneries remained in operation, and in 1919, the last one closed. Having captured the easy pickings of fish moving on their way upstream to breed, commercial salmon fishing was forced to move to the ocean, where it has remained to this day.

Hapless sea lions got blamed for the decline in 1886, just like today. Of seals, the commissioners stated that they "sit at the entrance of the Golden Gate as royal toll gatherers and take the lion's share of the schools of the finny tribe as they pass from the broad Pacific into the Bay of San Francisco..." The commissioners urged, without success, the repeal of legislation that protected sea lions.

Recently, however, the National Marine Fisheries Service authorized a special capture of seals at the mouth of the Columbia River, an action that is unlikely to lead to salmon recovery and one that should not be repeated in California.

Multiple causes, perhaps as many as 40, have been identified as possible agents of the contemporary decline. Many on our list of culprits were identified in 1886 - over-harvesting, dams that stop the spawning movements of salmon, diversion of freshwater to the Central Valley for agriculture and the siltation from erosion (due now to deforestation but in those days caused by the legacy of Gold Rush mining in the foothills). Now, we can add climate change, which warms the oceans and robs young salmon of their foods.

Better science is needed to diagnose the causes of decline and to determine their relative influences - a difficult, yet required, task for recovering any threatened species.

The commissioners in 1886 expressed confidence that salmon fry produced in California hatcheries would restore the stock. Hatcheries have forestalled the ultimate decimation of the salmon, but at the same time they create genetic and behavioral changes in salmon and may introduce diseases.

Hatcheries disguise the long-term problems facing salmon, and create a put-and-take fishery that can never lead to self-sustaining populations.

The salmon fishery must be closed temporarily to both commercial and recreational fishing as the first step for recovery, and smaller limits will probably be needed in the future. Serious consideration must next be given to removing dams and reducing water diversions in the Central Valley, restoring many watersheds and reducing agricultural run-off, while we work to abate climate change. The pain must be shared by all. We can't let the sea lions be the "fall guys" forever.

Steven R. Beissinger is a professor of conservation biology at UC Berkeley, where he holds the A. Starker Leopold Chair in Wildlife Biology. His research addresses the causes of decline, risks of extinction and recovery options for endangered species.