The journey to the ocean was quicker than usual for hundreds of tiny Chinook salmon that were released into the San Francisco Bay this week.
For another batch of the young fish, the trip will take longer via the Sacramento River.
This week, 300,000 juvenile salmon, called smolts, were released by the Feather River Fish Hatchery through an experimental program designed to see whether fish released into the bay survive better than those planted in the river.
Feather River Fish Hatchery Manager Anna Kastner said the 300,000 fish were all hatched from eggs gathered last year at the Oroville facility.
Three separate batches were released Tuesday and Wednesday, the last releases in the final year of a three-year barging experiment, Kastner said.
On Tuesday, Department of Fish and Wildlife employees took two truckloads of the juveniles, each with 100,000 fish, to Rio Vista. One load, control group A, was released into the Sacramento River to migrate naturally to the ocean.
The other load, group B, was placed into circulating water inside a fishing boat called the Merva W that traveled down to Tiburon.
On Wednesday morning, the last 100,000 smolts, group C, were trucked from Oroville to Tiburon, where they were transferred onto the Merva W and mixed with the 100,000 fish already on the boat.
All of those were then taken to a channel out in the bay and released.
Kastner said salmon live the majority of their lives in the ocean.
After the eggs hatch, the fish hatchery keeps them until they reach a certain size, where their bodies start to change so they can live in the ocean.
Although the salmon are born in freshwater, when they reach about 3 inches or 4 inches, they start migrating to the ocean.
"The fish are big enough that they will make the transition to salt water just fine," Kastner said.
The fish were put in the barge and in the river to see how they migrate. To find out, each juvenile was implanted with a tag containing a unique ID.
"When they come back, we'll look for the tag and will know where those fish came from," Kastner said.
It could take three to four years for the salmon to return.
"We don't know how well they're going to do in the ocean," Kastner said. "We'll just have to wait until they return, and see."
