Photo of Delta smelt courtesy of Department of Water Resources
Delta smelt population plunges to a new record low
by Dan Bacher
The population of Delta smelt, an indicator species that demonstrates the health of the Sacramento-San Joaquin River Delta, has declined to a new record low population level, according to the spring 2016 surveys conducted by California Department of Fish and Wildlife (CDFW).
The January Kodiak Trawl survey produced only seven fish, while the February survey yielded just six smelt. The Delta smelt once numbered in the millions, but have plummeted after decades of massive Delta water exports, combined with the impacts of declining water quality and invasive species.
"Once the most abundant species in the estuary, we can now name smelt rather than count them," said Jennings, Executive Director of the California Sportfishing Protection Alliance (CSPA).
The Delta smelt collapse is part of an overall ecosystem decline. The California Department of Fish and Wildlife’s 2015 Fall Midwater Trawl demonstrates that, since 1967, populations of striped bass, Delta smelt, longfin smelt, American shad, splittail and threadfin shad have declined by 99.7, 98.3, 99.9, 97.7, 98.5 and 93.7 percent, respectively, according to Jennings.
These percentage declines are reflective of the other 2015 surveys, including the 20 mm, Smelt Larva, Spring Kodiak and the Summer Townet Surveys. noted Jennings. For example, the 2015 Townet Index for Delta smelt was "zero," the lowest in the 56-year history of the survey.
"And so far in 2016, survey results are even more dire," said Jennings. "The first Spring Kodiak Trawl of Delta smelt showed a 67% decline from the record low of 2015 (which was 86% below 2014). The first Smelt Larva Survey found no Delta smelt (same as last year) and showed a 29.5% decline in Longfin smelt from 2015’s record low (which was 82% below 2014)."
Jennings emphasized that "Mother Nature did not cause the estuary’s biological collapse," in spite of the claims by state and federal officials that the "drought" is the cause of the collapse.
"It is the result of illegal political decisions by state and federal regulatory agencies that have become captive to powerful special interests," he stated.
He noted that these fisheries "evolved and prospered over thousands of years and survived the hundred-year mega droughts of the past."
"Since 1995, DWR and USBR have fully complied with Bay-Delta water quality objectives in only 8 of 21 years," according to Jennings. "The State Water Board has never taken an enforcement action for the thousands upon thousands of violations."
"In addition, the State Board has routinely waived compliance with legally promulgated criteria explicitly enacted to protect fisheries and water quality during critical drought sequences. And the fishery agencies have consistently acquiesced in these actions," he said.
Delta smelt are very near extinction in the wild - and Dr. Peter Moyle, UC Davis fisheries scientist, professor and author, is not optimistic about their potential recovery.
”We are entering uncharted waters with the delta smelt now because populations have never been so low,” said Dr. Moyle. "My guess is that populations are so small now that random events, such as predation by a swarm of silversides on eggs and larvae in an isolated spawning event, can keep driving the population down."
“These March rains are the best hope for any short-term recovery (as in 2011) because they should result in somewhat increased outflows from local run off in the Sacramento Valley, decreasing temperatures, increasing turbidity, diluting contaminants and other factors: all good for smelt,” said Moyle. “We are clearly close to extinction in the wild but whether we will see the last wild smelt in 2 years or 10 is anyone's guess."
"Presumably there is still a small probability of a miraculous recovery, but I am not optimistic, especially if we go back to drought conditions," he concluded.
As Delta smelt populations near extinction, recreational, tribal and commercial salmon fishermen face restrictions this year, due to the low abundance estimates for Sacramento and Klamath River Chinook salmon. As is the case with the Delta smelt, salmon populations have plummeted due to massive water exports out of the Sacramento-San Joaquin River system and the Trinity River, the largest tributary of the Klamath, along with poor management of northern California reservoirs by the state and federal governments and declining water quality. (http://fishsniffer.com/index.php/2016/03/03/sacramento-and-klamath-river-salmon-ocean-abundance-estimates-are-down-in-2016/)
Rather than trying to restore these fish populations, the Brown administration appears to be moving in the opposite direction as the Governor promotes the California Fix to build the Delta Tunnels as a "legacy project." The construction of the Delta Tunnels would hasten the extinction of Sacramento River winter Chinook salmon, Central Valley steelhead, Delta and longfin smelt, green sturgeon and other species, along with imperiling the salmon and steelhead populations of the Klamath and Trinity rivers.
In response to a request to my questions about the causes of the Delta smelt decline and the future of the fish, a representative of the California Department of Fish and Wildlife has not responded.
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