Once-bustling marinas on shallow water in California's largest lake a few years ago are bone-dry. Carcasses of oxygen-starved tilapia lie on desolate shores. Flocks of eared grebes and shoreline birds bob up and down to feast on marine life.

An air of decline and strange beauty permeates the Salton Sea: The lake is shrinking — and on the verge of getting much smaller as more water goes to coastal cities.

San Diego and other Southern California water agencies will stop replenishing the lake after 2017, raising concerns that dust from exposed lakebed will exacerbate asthma and other respiratory illness in a region whose air quality already fails federal standards.

A smaller lake also threatens fish and habitat for more than 400 bird species on the Pacific flyway.