Sunday November 4, 2007
The Modesto Bee
November 4, 2007
By Michael Mooney
The fish are jumping, but in apparently dwindling numbers, as the spawning season for salmon nears prime time in the Northern San Joaquin Valley.
Traditionally, most spawning activity on the Stanislaus, Tuolumne and Merced rivers occurs during the second and third weeks of November.
“So far, the numbers are very low,” said Tim Ford, an aquatic biologist with the Turlock and Modesto irrigation districts. “There’s no way to know for sure, but right now, it looks like it could be a bad year.”
Preliminary salmon counts also are showing fewer fish returning to the Sacramento, American and Feather rivers.
“It’s the same thing almost everywhere on the Pacific Coast,” said Doug Demko of FishBIO, a consulting firm with offices in Oakdale and Chico. “On the Stanislaus, we’re down about 90 percent from four years ago.
“But this year, definitely, is the most concerning.”
Demko and other experts believe changing conditions, including warmer water temperatures in the northern Pacific Ocean, could be behind the apparent decline.
Walt Ward, the district’s assistant general manger for water operations, said the myriad problems afflicting the delta could be factors.
“Predatory striped bass, water quality and temperature problems, the delta pumping — there’s probably no one single cause.”
MID General Manager Allen Short, for one, believes predation has been underrated as a possible cause for the apparent decline in salmon returning to spawn.
“Things are out of balance (in the delta),” Short said. “Salmon are getting slaughtered by stripers.”
Ward said water flows into the Tuolumne from Don Pedro Dam are regulated by the federal government with an eye toward preserving chinook salmon.
“You can only do so much,” Ward said, “and even if you do it perfectly, you still may not meet your objective.”
Demko agrees that predation — striped and black bass feeding on baby salmon, also referred to as smolt — likely has been underrated as a problem.
But he said he believes the conditions in the Pacific Ocean are the primary reason behind this season’s so far paltry salmon numbers.
“Ocean conditions are critical,” he said.