Lagunitas Watershed in Marin County is a prime breeding ground for the endangered coho salmon. Once rain swells the creeks, the fish return from the ocean to their freshwater birthplace to spawn. With declining numbers of salmon in the recent past, environmentalists are closely counting this year’s returnees. So far, they are hopeful.
Three years ago, only 26 redds were counted in the Lagunitas Watershed. So far this year, the nests number 55. Some environmentalists say this represents as much as a 95 percent drop from salmon numbers in the 1940s.
ADAPTABLE, ATHLETIC, DETERMINED
Cohos spend the first year and a half in freshwater creeks before migrating to the ocean, where they grow to two feet long. Before their third year, they travel 20 miles “home” to spawn. Some scientists say they smell their way home; others claim they can read the earth’s magnetic pull. The fish can jump up to six feet; most arrive battered and exhausted.
REDD, RED, READY
The female digs a hollow (up to 12 inches) with her tail. Her nest is called a “redd” from a Scottish word meaning "to tidy up.” During the journey upstream, the males turn reddish-maroon and grow hooked noses — called kypes — used in fighting the competition for the ready females.
EGGS IN ONE BASKET
The females each lay 2,000 eggs, over which the quivering males emit their milt. “These fish overcome anything natural the river puts in their way,” said Jonathan Appelbaum, a scientist who guides creek tours for a local environmental group. “What stops them is what humans have built.” The 227-foot-tall Peters Dam, built in 1954 to catch water from Mount Tamalpais, blocked the Lagunitas Creek and prevents fish from going farther upstream.
DYING FOR IT
The coho die within two weeks of mating. Birds of prey usually feast on the carcasses.
UP A CREEK
After six weeks, hatchlings wriggle up through the pebbles covering their nests. Threats to the young fish include egrets and heavy rain, which might wash them out to sea — where they would face still more predators. Residential development, sediment in the water and pollution from water runoff can also threaten salmon life.