Comment on Presidio’s Mountain Lake begins revival with native fish

Historic Mountain Lake in the Presidio came alive Wednesday as biologists and volunteers prepared to replant it with the first native fish to swim there since decades of toxic pollution turned its water into a virtual refuse pit. Hundreds of three-spined sticklebacks, to be transported to the lake Wednesday afternoon from nearby Lobos Creek, marks a major step in a restoration effort that has taken more than five years of dredging and the removal of hundreds of invasive critters — from koi to full-grown carp, discarded pet turtles, and even an alligator. Before the fish could be brought in, biologists had replanted the lake with native vegetation to make the water hospitable for the sticklebacks and other native creatures still to be re-introduced there. Early Wednesday morning, biologist Jonathan Young, the Presidio’s resident ecologist, carried a l48-quart cooler and a dozen 10-gallon plastic buckets down a park trail leading to the creek, the last free-flowing stream in San Francisco. The creek, which flows into the nearby Presidio’s water treatment plant, at one time served as early San Franciscans’ major source of water and still fills much of the park’s water needs. At the final stretch of the creek’s meander, Young and his team of Presidio interns netted more than 150 of the tiny swimmers and deftly dropped them into the cooler. Soon, Young and his team were driving their native fish to Mountain Lake’s eastern shore, where a crowd of Presidio workers and volunteers were ready with water-filled cups to help transfer the fish into their new aquatic home.