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About 68 years ago, the 35,000-acre Salton Sea National Wildlife Refuge was established as habitat for migrating waterfowl at the southern tip of the Salton Sea, California's largest inland body of water. More than 380 species have been spotted by bird watchers at the Salton Sea, but the sea has been dying a slow death for many years. Its inhabitants have been dying more quickly and in increasing numbers as the sea becomes saltier from a combination of more salt carried into the sea in runoff from industrial agriculture and an evaporation rate of about six feet a year, which concentrates the salt.
The sea was formed in 1905 when the channelized Colorado River burst a dike and spent 16 months flooding an ancient dry lake, the Salton Sink. With no outlet to the sea, water, which is 25 percent saltier than the Pacific Ocean, only gets out through evaporation. The weather is unforgiving: 100-degree-plus daily temperatures for six months of the year and less than an inch of rain a year. Thirty-three thousand acres of wildlife refuge are water in a sea whose only supply is industrial agriculture runoff from surrounding lands, and the polluted New and Alamo Rivers, which flow north from Mexico. Thirty-two years ago researchers confirmed that rising salinity of the 35-mile-long, 10-mile-wide lake would kill fish. Boy, were they ever right. Over the years, fish deaths were blamed on low oxygen levels, but more recently the blame has been shifted. An excellent four-page Salton Sea special in The Desert Sun on Oct. 1, 1997, reported that "dead fish frequently rise up to blanket acres of the sea's surface, then slowly sink back into the brine." In 1997, refuge staff saw a "raft of dead fish three miles long." Tilapia, an African warm-water fish introduced to eat vegetation, sometimes litter the shore in such numbers that it is difficult to walk around them, according to the newspaper. The suspected causes? Acute bacterial infections in 1996 and early 1997. Infestations of a lethal parasite in late summer 1997. Algal blooms. No one knows for sure. As the fish and other aquatic species go, so go the birds. In 1992, 150,000 eared grebes and ruddy ducks died, some of avian cholera, most of unknown causes. Another 20,000 water birds died in 1994, possibly of avian botulism, but no one knows for sure. Avian botulism was blamed for another 14,000 bird deaths in 1996, including more than 1,400 brown pelicans, an endangered species. Another 14,131 sick birds recovered "including 8,538 American white pelicans and 1,129 brown pelicans between Aug. 15 and Nov. 21." According to The |
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