RAINS: Coho salmon boomed in Marin this month: 181 were counted in Lagunitas, San Geronimo and Devil’s Gulch Creeks as of Dec. 16—the most since 2006, according to Marin Municipal Water District aquatic ecologist Eric Ettlinger. “I often hear people say that salmon runs are larger in wet years, but appearances can be deceiving,” he wrote in an email. “Rain determines when and how far the fish swim upstream, and so influences how many people see them, but rain can’t produce more fish. But here we are with lots of rain and lots of fish.”   Susan Adler