Point Reyes Light - December 30, 2004
Coho, steelhead, making a comeback
By Jim Kravets
This week’s storms, which flooded residents in low-lying areas, were good news for stream monitors working in West Marin.
Acquatic ecologist Eric Ettlinger of Marin Municipal Water District reported that observers counted 344 coho in one week, breaking a 10-year-record. In San Geronimo Creek alone (which does not include any tributaries), 263 coho were identified. His report found two confirmed steelhead trout. Immature steelhead and coho are difficult to distringuish, he noted.
Hydrologists Mark Woyshner and Anne Ardillo of Balance Hydrologics in Berkeley traveled to Lagunitas this week to measure San Geronimo Creek. Their data has helped Marin Municipal in its study of habitat for coho salmon and steelhead in the watershed.
Woyshner and Ardillo on Tuesday were measuring the flow of water and sediment in San Geronimo Creek at the Lagunitas Road Bridge. The hydrologists measured sediment rolling on the creekbed and calculating the speed of the current. Relatively little fine sediment was being carried along the creekbed, which is good news for spawning fish, Woyshner told The Light.
"Fine sediment silts up the redds [beds where salmon lay eggs] and deprives fish of oxygen," he said.
Balance Hydrologics has taken measurements of Lagunitas Creek since the 1970s, allowing Woyshner to identify positive trends for the health of the watershed.
"The erosion-control efforts of environmental group have been effective," he said, crediting activities such as upstream bank stabilization by Forest Knolls-based Salmon Protection and Watershed Network (SPAWN) and others for the stream’s encouraging checkup.