Coho salmon migrating toward the ocean this week were killed by a sudden water-level drop in a Russian River tributary near Healdsburg, the result of efforts to protect crops from frost, officials said.
The deaths of the endangered sal-mon add urgency to a multi-agency task force meeting, scheduled Tuesday in Sacramento, aimed at finding ways to protect crops from frost while preserving threatened and endangered fish in the Russian River and its tributaries.
"We are very concerned about the situation," said Dan Torquemada, a special agent with the National Marine Fisheries Service.
His agency's law enforcement arm, the state Attorney General and the Sonoma County District Attorney's Office are investigating this week's fish deaths and are giving no further details, he said.
Tuesday's meeting in Sacramento before the state Water Resources Control Board stems from another fish kill under similar circumstances last year, one the federal fisheries agency had predicted would be repeated this year.
When freezing temperatures hit the North Coast in April last year, farmers simultaneously pumping water for frost protection caused a sharp drop in the Russian River and some tributaries, stranding and killing a "significant" number of newly hatched salmon "fry."
The fish kills were in Felta Creek in Sonoma County and the Russian River near Hopland in Mendocino County, fisheries officials said. Exact numbers of fish deaths were not available.
The fish deaths last year spawned the creation of a task force that includes federal, state and local water and fish agencies and farmers. The group has been working since June to find solutions to the problem, which has been worsened by the ongoing drought.
"It seems imperative to act now," Steven Edmondson, the agency's Northern California habitat supervisor, wrote in a February letter to the water board.
The letter sent shock waves through the farming community.
Farmers in Sonoma and Mendocino counties are worried the state will ban frost protection this spring and force additional regulations on Russian River water users.
Local water agencies and farmers along the Russian River do not want a frost ban or additional state regulations, which could include a state-appointed "water master."
Water diversions from the Napa River for frost protection purposes have been under the control of a water master since the 1970s.
The program prevents farmers from pumping from the river all at the same time or individually taking more than their share.
The water master program is restrictive to some degree, but "generally I think it's a very good program," said Ross Hall of Swanson Vineyards in Napa County.
Sonoma and Mendocino counties farmers and water officials prefer to solve the problem locally.
"We don't want to see a water master," said Sonoma County Water Agency spokesman Brad Sherwood.
The Sonoma County agency, which controls water releases from Lake Mendocino into the Russian River, has been working with Mendocino County water agencies and farmers to better coordinate frost water demand with water releases from the dam to avoid sudden drops in river levels.
The agency also must conserve water in the lake -- which is at a near-record low -- for domestic and farming uses and fish later in the year.
The Russian River Flood Control and Water Conservation Improvement District on Tuesday will present proposals for better regulating water at the local level.