SULTAN — Thousands of salmon migrate up rivers in Snohomish County to spawn every year. But most pink salmon come back only every two years.
“No one knows exactly why. It’s just the way it is,” said Suzi Wong Swint of Snohomish County Surface Water Management.
This fall, more than 20,000 pink salmon are expected to run up the Sultan River to spawn, Swint said. People are invited today to Osprey Park in Sultan to watch the salmon, which get the nickname “humpbacks,” or “humpies,” because of the enormous hump that males develop during spawning season.
Pink salmon live for two years and return from salt water to rivers in the Puget Sound area in odd-numbered calendar years. (A small number do return in even-numbered years). If people want to see this number next year, they will have to travel to Alaska or British Columbia, she said.
The Sultan River gets a big run of pink salmon partly because it has a hydroelectric dam upstream, Swint said. That keeps the water level high downstream in summer.
The county has held an event to let people watch pink salmon return in Sultan in 2003 and 2005, she said. County officials try to use the event to educate people about salmon in the county.
While local rivers get a strong return of pink salmon, fish biologists are concerned about the sliding population of the coho and chinook salmon, Swint said. After hatching, the coho and chinook spend about a year in rivers before heading to salt water. As development has taken out trees and shrubs along rivers and creeks, the number of the coho and chinook has declined, Swint said.
Each salmon is unique, Swint said. Some are shy; others are outgoing. If people come out to the Sultan River today, they can get close to pink salmon.
“They are fun to watch in spawning season because they are not afraid of people,” she said.