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Experts vary on Stan River predation estimates
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Editor, Manteca Bulletin,
In his recent letter to the Bulletin, Mr. Wayne Flora raises a number of issues about the Save the Stan outreach effort, sponsored by the South San Joaquin and Oakdale Irrigation Districts. The fact that he raised the issues is exactly the reason we launched the program. It offers both districts the opportunity to present the facts to the community so people can make informed decisions. The education afforded by these discussions, we hope, will raise the level of understanding on a very real and important watershed issue, predation of native fish species in the Stanislaus River.

In regard to the predation estimates, Mr. Flora is correct. No one knows for sure, not even the experts, how many big fish are eating little fish. But the range of even the experts is startling and is an indication that all-is-not-right in the Delta. In a letter from Benjamin Z. Rubin from Nossaman, LLP to the California Department of Fish and Game (CDFG) Commission president on March 31, 2010, he cites to the Commission deposition testimony from CDFG’s own experts on the devastation of predation. These experts include Mary Gingras, Department Biologist, who estimates 5%-25% predation on winter run; Matthew Nobriga estimates 6%-50% predation on winter run; Dr. Charles Hanson, Independent Biologist, pegs it at 21% predation; David Kohlhorst, Former Department Biologist, thinks it is 30% predation.

Recently the National Marine Fisheries has been thinking along the same lines. They are experts and have begun telling CDFG to remove the take limits, the size limits and the season limits on striped bass. While all numbers are variable, the EXPERTS believe it’s somewhere south of 50%.

Under State definition a steelhead is “an anadromous rainbow trout with a silver coloration, popular for sport fishing.” Thus, if a rainbow trout by definition is a steelhead, as CDFG says it is, and the Stanislaus has 20,000 rainbows in the first six miles downstream from Goodwin, we get credit for steelhead presence in the river. We didn’t make up the definition, the State did.

Concerning the dams, it is important to note that Goodwin is a diversion dam, and stores no water of significance. New Melones doesn’t serve the same function as Goodwin. Woodward Dam is an off-stream storage reservoir built in a small valley not connected to the Stanislaus River except by diversion. It has no ability to impact salmon runs because it’s not even on the river.

Agriculture is the life blood of this region and without sufficient water supplies this region will suffer as we have seen happen to our neighbors to the south. They are experiencing food lines and unemployment rates reminiscent of the Great Depression. We don’t want that impact here.

The two districts have provided thousands of acre feet of water to the Vernalis Adaptive Management Plan over the last 12 years. VAMP is an experimental/management program designed to find ways to enhance the fall-run Chinook salmon population which migrates from the east side of Sierra streams to the San Joaquin River and through the Sacramento -San Joaquin Delta. In the past 53 years we have spent millions of dollars on projects, too many to list here, to protect the native species in the river as part of our FERC License. No one has done more to protect steelhead and salmon on the Stanislaus River than the two districts. So when a non-native predator fish, whose numbers have grown to now consume somewhere south of 50% of those tiny native salmon, we feel compelled to speak up.

We take our stewardship role of the river very seriously and will continue to do so. We also recognize that our ag-based economy depends on a cooperative model in which we all work together to provide a sustainable, quality of life for everyone.

So to Mr. Flora and others who have questions, we welcome the opportunity to talk with them.

Jeff Shields, General Manager
South San Joaquin Irrigation District
Steve Knell, General Manager
Oakdale Irrigation District