Salmon: Run falls per­ilously low.

San Francisco Chronicle - - FRONT PAGE - By Kur­tis Alexan­der

One of Cal­i­for­nia’s last great salmon runs tal­lied a per­ilously low num­ber of sur­viv­ing off­spring in 2015, sci­en­tists said Mon­day, mark­ing a se­cond year of drought-driven prob­lems for the Sacra­mento River chi­nook, which loom on the verge of ex­tinc­tion.

The Na­tional Oceanic and At­mo­spheric Ad­min­is­tra­tion’s Fish­eries Ser­vice re­ported that just 3 per­cent of the run’s ju­ve­nile salmon sur­vived their his­toric mi­gra­tion to sea, again dy­ing in large num­bers be­cause the river was sim­ply too shal­low and too warm to tol­er­ate.

State and fed­eral of­fi­cials, af­ter wit­ness­ing a grim 5 per­cent sur­vival rate in 2014, took steps to boost river lev­els for the fish last year, most no­tably in­tro­duc­ing a con­tro­ver­sial strat­egy of with­hold­ing ir­ri­ga­tion wa­ter from Cen­tral Val­ley farm­ers. But that was to lit­tle avail.

“We just didn’t have enough cold wa­ter to work with,” said Maria Rea, West Coast as­sis­tant re­gional ad­min­is­tra­tor for the Fish­eries

Ser­vice. “De­spite ev­ery­body’s best ef­forts, the plan wasn’t ef­fec­tive in pre­vent­ing re­ally sig­nif­i­cant mor­tal­ity.”

This week’s dire fig­ures may por­tend even greater wa­ter re­stric­tions for agri­cul­ture in the fu­ture, as well as fur­ther lim­its on com­mer­cial and recre­ational fish­ing.

The com­ing year is cru­cial for the chi­nook salmon. The fish have a three-year spawn­ing cy­cle, mean­ing the next class will be the only one that hasn’t suf­fered a de­bil­i­tat­ing blow and rep­re­sents the last chance of spurring a re­bound for the fed­er­ally listed en­dan­gered species.

Fish in the run, one of three dis­tinct pop­u­la­tions on the Sacra­mento River, are born in the far reaches of North­ern Cal­i­for­nia and typ­i­cally make their way south through the Golden Gate to the Pa­cific Ocean, be­fore re­turn­ing to their fresh­wa­ter birth­place three years later.

All of the runs have suf­fered over re­cent decades as river wa­ter has been di­verted for farm­ing, and as valu­able habi­tat in the flood plain has been lost. But the win­ter pop­u­la­tion has fared worst.

Last year, wa­ter re­leases were lim­ited at Shasta Dam on the Sacra­mento River in the spring so there would be more wa­ter — and colder wa­ter — for salmon in the dry, warm sum­mer months.

Nev­er­the­less, too lit­tle wa­ter col­lected be­hind the dam be­cause of mea­ger moun­tain snowmelt dur­ing the drought. As a re­sult, tem­per­a­tures in the river rose from an ideal high of 55 de­grees to 58 de­grees at times, prov­ing a death knell for the young fish.

Farm­ers crit­i­cized the restora­tion plan as an­other that pri­or­i­tizes fish over farm­ing. Many had planted their fields in an­tic­i­pa­tion of get­ting ir­ri­ga­tion wa­ter in the spring, only to see crops die of thirst af­ter re­leases at Shasta were cur­tailed.

En­vi­ron­men­tal groups and fish­er­men, how­ever, said too lit­tle was still be­ing done to pro­tect the fish. On Mon­day, the Golden Gate Salmon As­so­ci­a­tion was among the first to call for more re­stric­tions on wa­ter re­leases.

“Salmon fish­er­men and their fam­i­lies will pay a price for wa­ter al­lo­ca­tion de­ci­sions made by oth­ers that dec­i­mated win­ter-run salmon in the Sacra­mento River the last two years,” said John McManus, the as­so­ci­a­tion’s ex­ec­u­tive di­rec­tor.

The Fish­eries Ser­vice man­ages a salmon hatch­ery that it ex­pects to help stop the chi­nook’s down­ward spiral, but Rea said a new plan to en­sure ad­e­quate cold wa­ter is vi­tal.

Fed­eral of­fi­cials are rec­om­mend­ing that a high of 55 de­grees is main­tained on the river, an ef­fort that Rea says hinges on the weather.

“Whether or not they can meet that is go­ing to de­pend on hy­drol­ogy and whether it keeps rain­ing and how much snow we get,” she said.

Michael Ma­cor / The Chron­i­cle 2015

A hand­ful of win­ter-run chi­nook salmon are seen at the fed­eral fish hatch­ery in Shasta County. The species is close to ex­tinc­tion af­ter years of drought.

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