Continued drought leads to another year of high mortality rates for salmon returning to the ocean

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Conservationists are concerned about the winter migration of Chinook salmon, as the population continues to decline during years of persistent drought. Last winter marked the third in a row with below average rainfall and snowfall in many places, leading to lower water levels in major rivers. Less water is bad news for schools of salmon, which swim from spawning grounds near Shasta Lake out to sea each spring. Lower water levels generally lead to clearer water overall, which makes it easier for predators to spot fish. The water is also warmer, causing the fish to swim more slowly. Arnold Ammann is part of a team of scientists tracking salmon as they move downstream in March and April. He said that this year only 4% of the approximately 500,000 fish survived the entire trip. drought conditions, Ammann said these low numbers were expected. In a year with higher amounts of precipitation, up to 25% of the salmon population reaches the ocean. But after three dry years, conservationists are increasingly concerned, especially since the average lifespan of salmon is just three years. They know where those calculations point. Due to the continued risk to already endangered species, scientists are updating conservation methods in Northern California. Adult salmon are moved from Keswick Dam to Battle Creek, where the water is generally cooler in the warm season. Experts hope this will help support a good spawning season. Fisheries will also use riverside incubators that provide sheltered space for fish. eggs to develop in naturally flowing river water.

Conservationists are concerned about the winter migration of Chinook salmon, as the population continues to decline during years of persistent drought.

Last winter marked the third in a row with below average rainfall and snowfall in many places, leading to lower water levels in major rivers.

Less water is bad news for schools of salmon, which swim from spawning grounds near Shasta Lake out to sea each spring.

Lower water levels generally lead to clearer water overall, which makes it easier for predators to spot fish.

The water is also warmer, causing the fish to swim more slowly.

Arnold Ammann is part of a team of scientists tracking salmon as they move downstream in March and April. He said this year only 4% of the estimated 500,000 fish survived the entire trip.

“It’s quite low compared to other years. It’s a bit higher than 2020 and 2021. Those years were around 2 and 3 percent,” Ammann says.

Given the persistent drought conditions, Ammann said these low numbers were expected. In a year with higher precipitation, up to 25% of the salmon population reaches the ocean.

But after three dry years, conservationists are increasingly concerned, especially since the average lifespan of salmon is just three years. They know where the math points.

Due to the continued risk to already endangered species, scientists are updating conservation methods in Northern California.

Adult salmon are moved from Keswick Dam to Battle Creek, where the water is generally cooler in the warm season. Experts hope this will help support a good spawning season.

The fisheries will also use streamside incubators which provide a sheltered space for fish eggs to develop in the naturally flowing river water.

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