Heat and drought blamed for delay in famous annual migration from Pacific Ocean to inland spawning grounds, reports The Guardian through it's online news service. ii
The annual autumn migration of Chinook salmon has been delayed by warmer water temperatures and slow-flowing streams in parts of California as the state’s three-year drought drags on, hatchery officials have said.
Cool November temperatures usually bring thousands of adult salmon from the Pacific Ocean into streams and rivers to spawn. But this year fish were slow to migrate up the American River to the state’s hatchery near Sacramento, said William Cox, manager of the fish production and distribution program at the California fish and wildlife department.
“They haven’t come into the river at the same time that they would normally,” Cox said.
Wildlife researchers check the strength of the fall salmon run by going out to creeks and rivers and counting them. This year in the American River and its tributaries, the survey crews found just 210 corpses of salmon that had presumably spawned and died in the streams, a tenth of the number normally encountered, Cox said.
At another hatchery, near the Central Valley city of Merced, a higher than normal number of male salmon were arriving but unable to provide viable sperm to spawn, he said.
State wildlife experts are not entirely sure why the salmon are late but some speculate that warmer temperatures and slower flow in the American River might be to blame, reports The Guardian.
Read more HERE.
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| Slow-flowing rivers and warmer waters blamed for delayed salmon run in California |
The annual autumn migration of Chinook salmon has been delayed by warmer water temperatures and slow-flowing streams in parts of California as the state’s three-year drought drags on, hatchery officials have said.
Cool November temperatures usually bring thousands of adult salmon from the Pacific Ocean into streams and rivers to spawn. But this year fish were slow to migrate up the American River to the state’s hatchery near Sacramento, said William Cox, manager of the fish production and distribution program at the California fish and wildlife department.
“They haven’t come into the river at the same time that they would normally,” Cox said.
Wildlife researchers check the strength of the fall salmon run by going out to creeks and rivers and counting them. This year in the American River and its tributaries, the survey crews found just 210 corpses of salmon that had presumably spawned and died in the streams, a tenth of the number normally encountered, Cox said.
At another hatchery, near the Central Valley city of Merced, a higher than normal number of male salmon were arriving but unable to provide viable sperm to spawn, he said.
State wildlife experts are not entirely sure why the salmon are late but some speculate that warmer temperatures and slower flow in the American River might be to blame, reports The Guardian.
Read more HERE.
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