Droughts lead to California's biggest salmon hatchery driving millions of fish to the coast

More than 13 million fish have been transported to the San Francisco bay

Salmon being released into the San Francisco Bay (Justin Sullivan/Getty Images)

Pacific salmon are known for their great migrations.

Moving across continents, they can travel thousands of miles to find the ideal waters to breed in.

Usually they do this by swimming, but recently salmon in California have used transport to ensure their annual migration is completed.

However, this year instead of taking the three week journey to the coast, salmon are loaded onto a lorry and driven for four hours to the San Francisco Bay.

According to Brett Galyean, this is largely down to the low water levels along the Sacramento River.

He said: “If we release them out into they would experience maybe low water and warmer water, which would provide stress to them and give predators a better chance at eating them. ”

To transport the salmon, the fish are sucked up 60,000 at a time into the massive tanks where they are held in cold water and driven to the San Francisco Bay.

They are finally driven to the coast in massive tankers (AFP)

It is here that they are released into the bay, where after being held for a couple of hours are set free and sent to find their way to the Pacific Ocean.

The salmon fishing industry in the US is said to be worth billions of dollars and provide a lifeline for certain communities along the migration routes.

They are then dropped into nets in the bay before being released (AFP)

Steve Martano, a worker for the Fish and Wildlife Service said: “This is not our usual procedures but this is the best we can do under the circumstances.

“At least now we will get some kind of ocean harvest and some kind of benefit to the ocean fishery.”