Just who - or what - is depleting the ranks of salmon and steelhead in the Stanislaus River as well as the Delta?

The two agencies that have served as Stanislaus River stewards since 1998 by creating habit for native species and to keep track of fish movements point to predators that are non-native fish such as bass.

A biological opinion issued in 2009 by the National Marine Fisheries Service contends it is inadequate releases from New Melones Reservoir that are imperiling steelhead and salmon.

Based on hydrology data collected over the past 80 years, if that opinion had been used to implement river flows on the Stanislaus River assuming New Melones Reservoir had been built in 1931 it would have been emptied 13 times. Using current flow patterns the reservoir would have gone empty just once in the past 80 years.

That is not the only reason the two agencies serving as stewards of the river - South San Joaquin Irrigation District and Oakdale Irrigation District - have formed the Save the Stan effort.

Lowering New Melones Reservoir below 500,000 acre feet would effectively eliminate “cold storage” where fish thrive.

“The biological opinion if used by the Bureau (of Reclamation) to implement an operational plan would effectively kill off the very fish they want to save,” noted SSJID General Manager Jeff Shields.

That’s because the large releases would reduce water levels enough that the average temperature of the storage at New Melones would rise 10 degrees. It essentially would “cook” the fish to death.

The two districts have gotten the ear of California Senator Dianne Feinstein who is pushing for an independent scientific review of the biological opinion. The National Marine Fisheries Service indicated they used abstract modeling to develop the biological opinion as they lacked the resources to collect thorough data on the Stanislaus.

It is just that - thorough data - which the two agencies armed themsleves with in trips to Washington, D.C., and Sacramento to educate fisheries and water agencies that the biological opinion is flawed as well as being dangerous to the fish they are trying to save. It also would have the potential of putting more than 50,000 acres of farmland in the two districts out of production.

The two districts have spent more than $10 million over the last 13 years improving fish habitats and monitoring fish movements. It includes state-of-the-art in water video systems, weir counts, as well as snorkel and seining surveys to determine the abundance and distribution of non-native fish species. This information is used to determine the potential impacts of non-native predators and competitors on native salmon and steelhead.

OID and the U.S. Fish and Wildlife Service are jointly funding a habitat restoration project at the Honolulu Bar Recreation Area. It is designed to increase spawning and rearing habitat for salmon and steelhead.

The Save the Stan effort also points to various state fish biologists who attribute the loss of salmon and steelhead population due to predation from non-native fish in the Delta. Their estimates run as high as 30 percent. Non-state biologists have indicated the number could push 50 percent of all native fish being loss to predators.

As such, some experts are suggesting that the California Department of Fish and Game remove take limits, size limits, and season limits on stripped bass.

A similar program was effective in the Pacific Northwest at keeping non-native predators in check.

Fishermen would catch a many as they could. They would then go to a licensing agent store where the heads of the predator fish were cut off. They were paid $5 per fish head as a bounty plus got to keep the rest of the fish.