Wet Winter, Spring Kind to Delta Smelt
Dec 23, 2011
The Delta smelt - that finger-long fish whose welfare was the subject of intense political debate during the recent drought - has rebounded to levels not seen in a decade, the California Department of Fish and Game reported Thursday.
But even after this year's 10-fold increase in population, the smelt remains but a fraction of its former abundance.
And that says something about the fish's perilous state in recent years.
The Delta smelt is tiny. It is not a sport fish and cannot, at current numbers, support a commercial fishery.
Why should anyone care about it?
The smelt is indicative of the health of the Delta itself, where two of the state's largest rivers come together west of Stockton before draining into San Francisco Bay.
Two-thirds of Californians get at least some water from the Delta. And the amount of water they can receive is dependent in part on the well-being of the 3-inch smelt.
"Hopefully, this is the start of a new trend," said Carl Wilcox, Bay-Delta regional manager for Fish and Game.
The most recent upswing can be attributed mostly to the fact that so much water flowed through the Delta following a wet winter and spring, Wilcox said. Fresh water flowing downstream can dilute pollution, create better feeding conditions and help the 3-inch smelt hide from predators and escape the influence of giant pumps near Tracy.
Cities and farms that take water from the Delta also got record-high deliveries this year, creating a rare confluence of events in which both fish and farmer prospered.
That wasn't the case during the three-year drought, when some farmers south of the Delta got less water as the federal government attempted to protect smelt and other species. The cutbacks triggered intense arguments about endangered species laws and reinvigorated discussion of building a peripheral canal or tunnel to bypass the Delta entirely.
"A 10-fold increase (in smelt) was definitely beyond my wildest hopes for the species," said Jon Rosenfield, a biologist with the environmental group The Bay Institute. "I think this number buys us a little bit of time to enforce the protections and do the other things, like habitat restoration and water-quality cleanup, which we need to do."
Smelt weren't the only species to benefit from lots of water rolling through the Delta. Striped bass - a favorite among local fishermen - rose to an abundance not seen since 2006 after declining to a record low in 2010.
Longfin smelt - a cousin of the more notorious Delta smelt - and two species of shad also became more prevalent.
Perspective, however, is sobering.
The number of smelt this year is still only about 20 percent of the number seen in 1970, the best year on record.
The number of stripers is less than 1 percent of the number seen in 1967, the best year on record for that fish.
"We've seen a pretty good bounce," Rosenfield said. "I'm still not willing to state there's been a recovery."
Contact reporter Alex Breitler at (209) 546-8295 or email@example.com. Visit his blog at recordnet.com/breitlerblog.
BY THE NUMBERS
The Department of Fish and Game samples for Delta fish each fall and creates an index for each species based on how many are found. The index does not indicate the literal number of fish but can be used to compare changes over time.
Here's what the surveys found:
This year Last year Historic high
Delta smelt: 343 29 1,673
Striped bass: 272 43 19,677
Longfin smelt: 477 191 81,737
Threadfin shad: 228 120 15,267
American shad: 894 683 9,360
From the Silicon Valley Mercury News:
” … After a three-year drought that stoked political rhetoric pitting water users against the needs of Delta smelt, a wet 2011 saw a great year for both.
Record amounts of water were delivered from the Delta and imperiled fish numbers rebounded significantly.
A key annual survey showed Delta smelt numbers at their highest level since populations of smelt and other fish collapsed in the early 2000s. The index, 343, was more than 10 times greater than last year’s figure, 29. The last time the measure as high was 2001, when the index was 603.
“There are lots of factors that we’ll be examining in the coming months to evaluate what happened, but flow always helps,” said Carl Wilcox, Bay-Delta regional director for the California Department of Fish and Game. … “