A showdown is looming between grape growers and the agency tasked with protecting the fish in the Russian River.
Russian River grape growers are collecting data to counter a nearing state decision on how to protect endangered fish from the impacts of water pumping for frost protection.
The state Water Resources Control Board is contemplating new regulations along the river after federal fish managers declared that water diversions for frost protection have harmed salmon and steelhead.
Three environmental groups are pressuring the state to adopt strict rules. Last month the groups formally notified the water board of their intent to sue the state under the federal Endangered Species Act.
A spokesman for one of the three environmental groups said the fish will remain at risk of extinction unless the state takes decisive action and rejects the idea of self-regulation by growers.
"We don't really have time to sit around and spend 10 years discussing half measures that may or may not work," said Jeff Miller of the Center for Biological Diversity.
The other two environmental groups are Northern California River Watch and Coast Action Group.
Farm leaders in Sonoma and Mendocino counties counter that since the federal regulators brought the issue to the forefront in 2008, the grape growers have made great strides to reduce impacts on salmon and steelhead. That includes the construction of new reservoirs near Hopland, the site of fish strandings in 2008.
"We're here to protect fish as well, but it can't be done by eliminating the viticulture industry in Mendocino and Sonoma County," said Devon Jones, executive director of the Mendocino County Farm Bureau.
On freezing nights in spring, many growers spray water over their vineyards to protect the vines from damage. The irrigation water freezes and encapsulates the green buds in ice, keeping the plant tissue safe at a constant 32-degree temperature.