Chinook salmon eggs didn't hatch, hatchery fish come to rescue

Tuesday, February 10, 2015
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Since the drought increased the temperature of the Sacramento River eggs didn't hatch. Now, fish from hatcheries are coming to the aid.

SAN FRANCISCO (KGO) -- The Bay Area's weekend rainstorms gave a window of opportunity for a species that is really struggling to survive. Now, more than half a million salmon are riding a big wave down the Sacramento River.

As the Bay Area clears toppled trees and downed power lines, there's something else going on a little farther inland. A hatchery is going to release 200,000 individual fish. It will be the first load of 600,000 individual 4" winter-run Chinook salmon that will be released in total.

Endangered since the 1990s, the winter-run Chinook salmon still spawn in rivers and streams, but they need help.

"Because of the drought and elevated temperatures in the upper Sacramento River, the eggs didn't hatch. The eggs didn't hatch. They got too hot, they died," John McManus from the Golden Gate Salmon Association.

So these fish are being released from hatcheries to replenish the population.

California has two federal hatcheries, where biologists breed the salmon and raise them until they're old enough to swim downstream, hundreds of miles to the ocean. With these storms, they've decided to release nearly all of the fish that were ready because the rain makes for a golden opportunity, especially if it continues.

"A great big bubble of water coursing down the Sacramento Valley carrying a whole bunch of stirred up mud and sediment in the river water. That's as good as it gets. That mud and sediment acts as camouflage, protects those little fish from bigger fish that would love to eat them," McManus explained.

There's also another reason it needs to keep raining for those fish to make it out here to the Golden Gate Bridge. For all the natural predators that would eat young salmon for lunch, one of the biggest threats is actually man-made. Soon the water will be diverted from the Sacramento River into the inner delta.

Because so much of California relies on the water from this one river, the salmon are swimming amid a precious and limited resource. Pumping stations take some of this water down south to supply farms in the Central Valley.

"When they hit the delta, we're hoping that the pumping levels are not so high that they pull these fish in and kill them," McManus said.

A biologist at the Coleman Hatchery said it will take about a week for the fish to make it to the delta and they've asked the Bureau of Reclamation to close the gate to the pumps, so the fish can make it past. Of course, fish don't follow directions, so fishermen and conservationists can only hope they don't linger too long in the delta before making their way out to sea.