California continues to kill millions of fish

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Delta smelt are still on the verge of extinction

As massive amounts of water continue to be exported from the Delta, the Delta smelt are still in great peril, in spite of this being a wet year.

The 20-Millimeter Survey index of young Delta smelt abundance, developed yearly since 1995 and named after the approximate size of fish it collects, was 8.0 this year. By comparison, the index set a record high of 39.7 in 1999; in 2010 it was at the very low level of 3.8.

The Summer Tow Net Survey Index of slightly-older Delta smelt abundance, developed yearly since 1959 and named after the type of net used to collect fish, was 2.2 this year while the index in 2010 was 0.8 and the record high was 62.5 in 1978.

“The increased number of young Delta smelt is encouraging, but because it is still early in their one-year life cycle, the abundance of adults may or may not increase similarly,” according to Marty Gingras, DFG Supervising Biologist. “DFG will continue to monitor the population and at the conclusion of the Fall Midwater Trawl Survey in December will calculate and then release an index of sub-adult Delta smelt abundance.”

Because it is exceptionally difficult to determine the actual number of Delta smelt, Department of Fish and Game (DFG) biologists use survey data to develop “indices” of the species’ abundance. An index is a number that is likely to vary in direct proportion to abundance.

For example, if a hypothetical index were to double from 4 to 8 then abundance would also have doubled (e.g., from 200,000 to 400,000).

Smelt collapse part of a larger decline

Delta smelt are an indicator species that occur only in the Sacramento-San Joaquin River Delta. The finger-sized fish was historically one of the most abundant in the Delta. However, the species declined substantially due to massive exports of water to agribusiness and southern California and other factors, and was listed as “threatened” under the California and Federal Endangered Species acts (ESA) in 1993.

After a further decline, the species was designated as “endangered” in 2010 under the California ESA.

The collapse of Delta smelt occurs in the context of the Pelagic Organism Decline (POD). Since 2005, state and federal scientists have documented the alarming decline of pelagic (open water) species including Delta smelt, longfin smelt, threadfin shad and young striped bass. Factors behind the decline include increases in water exports, toxics, invasive species and ammonia pollution from sewage treatment plants.

“The state and federal governments had the opportunity this year to reverse the decline of Central Valley salmon and Delta fish species,” said Bill Jennings, executive director/chairman of the California Sportfishing Protection Alliance (CSPA). “But what they are doing now is minimizing the rebound of fisheries that occurs in a wet year by pumping water at the maximum rate. The fish ‘salvage’ numbers are just the tip of the iceberg of the fish that are lost in the state and federal pumps.”

Rather than taking long-needed action to stop the carnage at the water export facilities, the Brown and Obama administrations, in the footsteps of the Schwarzenegger administration, are instead pushing for the construction of a peripheral canal or tunnel through the Bay Delta Conservation Plan (BDCP) to facilitate the export of more northern California water to corporate agribusiness on the west side of the San Joaquin Valley and southern California water agencies.

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