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FYI - Limit Predation Saves Salmon

POSTED March 3, 2010 1:40 a.m.

“One fish. Two fish … Some are red. And some are blue. Some are old. And some are new. Some are sad. And some are glad. And some are very, very bad.” These lines from a famous Dr. Seuss book also symbolize the current imbalance of native Chinook salmon to non-native predator fish in the Delta waterways.

Predation by non-native species such as striped bass is a leading threat to our native salmon populations. Radio tracking tags on young salmon released into the San Joaquin River demonstrate that most end up in the stomachs of non-native predators. That’s undisputable scientific evidence.

Many other factors, some well known, others yet poorly understood, are affecting our native fish populations, too. This complex web of threats includes ocean conditions, the commercial fishing harvest, ammonia, other water quality problems and a declining food chain.

A recent proposal by Senator Dianne Feinstein to ease the federal protections on salmon is bringing much needed attention to finding a solution to the salmon decline without crippling agriculture. Major newspapers and environmental groups have been quick to throw mud on Senator Feinstein’s proposal. Opponents miss the major cause of the decline in the salmon fishery: predation by non-native species – the one threat that can be immediately and economically addressed.

Assembly Bill 2336 introduced this month by Assembly Member Jean Fuller puts predation by non-native species front and center in the development of the Sacramento-San Joaquin Delta Plan. This legislation supports evaluating predator suppression and seeks recommended changes in law and State agencies’ actions to promptly address and reverse the dangerous salmon decline.

Approximately 95 percent of Delta aquatic life is comprised of non-native species either preying on or competing with natives (Cohen and Carlton study, 1998). Interestingly, there is at least a 3-to-1 ratio of predators over adult fall-run Chinook salmon. AB 2336 can yield the relief needed to begin rebuilding salmon vitality. It requires little cost to taxpayers and shows promise of achieving quick results.

To date, efforts to help salmon recover have focused primarily on increasing river flows and turning off export pumps. Though salmon populations thrived in years when rivers ran dry naturally, many argue that much more water is needed to bolster and sustain the fishery.

For more than 10 years, the Modesto Irrigation District and our water agency partners have increased Tuolumne River flows (into the San Joaquin) each spring, meticulously monitoring and evaluating the effects. We have seen no guarantee that increasing river flows will succeed in reviving the declining salmon fishery. Providing even more water could cause devastating financial and job losses in Central Valley agriculture.

Take a look at the Pacific Northwest. In trying to help salmon, dams have been removed, river flows increased, other major concessions made costing millions of dollars, millions of acre-feet of water and countless jobs. Yet in 2008, salmon populations collapsed, resulting in the cancellation of the salmon fishery from California to Alaska. This resulted in an estimated $255 million economic loss to California. Most of the salmon fishery was cancelled again in 2009.

It’s naive and foolishly simplistic to focus on a single cause or solution as the cure-all for helping salmon. Let’s at least fix what we know first; what we can fix at little or no cost to California businesses and taxpayers. We know that non-native predatory fish like striped bass eat salmon smolts and lots of them. It’s time for new solutions such as AB 2336 that rationally address the proven threat of predation.

 

Allen Short serves as the General Manager for the Modesto Irrigation District.

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