Friday, September 3, 2010
The salmon in the Salmon
Chinook (King) and sockeye salmon travel over 900 miles to spawn in the Salmon River and lakes near Stanley, the longest fish migration in the U.S. We are excited to witness these salmon in the river across from our campsite and at various vantage points along the river. It is nearing the end of the sockeye migration, but another month for the chinooks. These fish travel 20-30 miles each day, and must travel past 8 dams (via fish ladders) and through several reservoirs, losing 30%-50% of their body weight along the way (they don't eat during this journey).
The Chinook are the largest of the three Pacific salmon historically native to Idaho. The young smolts being their journey to the Pacific when they are approximately 18 months old and 4 inches long. Their entire downstream trip is tail first and takes 2-3 months, all along the way their body chemistry adjusts to allow them to live in the saltwater. Sadly, 77-96% of the smolts die on their way to the ocean, and only 1/10 of 1% of them will make it back to spawn as adults. They travel thousands of miles in their 3-4 years in the ocean, before returning to their natal streams to spawn. They currently are a threatened species.
The sockeye are also known as "redfish" around here. They have a similar cycle as the chinnok, except they only spend 1-2 years in the ocean. At one time, the sockeye returned in the tens of thousands to spawn in Redfish Lake, so named because there were so many they made the lake appear red. In 2007, only 4 returned, but the number this year exceeds a thousand (better, but far from ideal). They are still an endangered species.
Currently there is a multi-agency federal/state effort to mitigate the losses of the salmon (and steelhead) on their migratory routes. Part of this is through hatcheries on the Columbia, Snake, and Salmon Rivers. They establish weirs aT specified points to divert the fish to tanks each night. Each morning, the fish are individually netted, and a whole team of biologists capture data, and then release them to complete their spawn - some of each species are kept at the hatchery to artificially spawn, some chinook are returned to the Salmon to continue their upstream journey to spawn, and some of the sockeye are returned to Redfish lake to continue their natural spawning.
After the salmon complete their spawn they die and their carcasses deteriorate in the bodies of water, providing valuable nutrients to the current and future inhabitants.
Sorry to be so lengthy on this, but this was such an invaluable and interesting lesson to us. And besides, when a species endures such hardships and high mortality rate to live 2-5 years at best, return home, make a little whoopee, provide the beginning of the next generation, only to then die, they deserve any credit and props they can get.
Chinook on their way
Female chinook
Got milt? Male chinook.
Sockeye
diversion weir
Where the Idaho sockeye finish their spawning. Not a bad place for any species to make their last whoopee before dying. Redfish Lake.
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