Turtle Die-off Raises Concern for Gray Whale Nursery in Baja California

Back to Map Page July, 1998 Laguna San Ignacio, Mexico In July news reports confirmed that the death of 94 sea turtles last winter resulted from toxic chemical releases at a Baja salt works operated by Mitsubishi Company and the Mexican government. The turtles were poisoned by lethal concentrations of salt sludge and brine released from holding ponds at the Guerrero Negro salt works at Laguna Ojo de Liebre. The plant produces salt by evaporating sea water. Water is pumped from the warm, shallow bay at a rate of some 5,000 gallons per second. Released into shallow evaporation ponds, the water evaporates in the desert sun and leaves behind a concentrated complex of minerals that are subsequently washed and purified to produce marketable salt. The remaining briny sludge is stored in holding ponds on the site, but a large release has now been confirmed as the cause of death for 94 dead turtles found by fishermen last winter. Damage to local fisheries, the subsistence economy for most of the area’s population, is unknown. A similar spill of 4 million gallons in May of this year also caused fish kills in the bay.   Laguna San Ignacio, on the Pacific coast of Baja California, is one of only a few long, shallow bays suitable for Gray Whale calving. . Spill Raises Concern for Whales These releases intensify existing worries about a newer, larger salt facility now being planned by Mitsubishi and the Mexican government just 140 km southeast of Guerrero Negro, at Laguna San Ignacio. The joint venture corporation behind both facilities, ESSA (Exportadora del Sal, S.A.), has repeatedly cited its existing salt works as evidence that the Laguna San Ignacio works will be environmentally safe. But the recent turtle deaths appear to confirm the fears of Mexican environmentalists that the salt works, and its planned annual production of a billion gallons of concentrated magnesium and bromide waste brine, may not be safe. Mexican environmentalists, led by El Grupo de los Cien, have objected to the proposed salt facility at Laguna San Ignacio from the beginning, and many US environmental groups have since joined the protest. The chief concern is that this long, warm, shallow bay is the most pristine of only three major gray whale calving grounds in North America. A growing tourism industry built on whale-viewing tours now augments the local fishing economy, which includes prime lobster and abalone fisheries. The salt works would require a mile-long pier reaching out into the shallow lagoon, a possible deterrent to whale movement. If frequent freighter activity doesn’t disturb the calving and nursing whales, oil spills during fuel deliveries, or brine spills like that at Guerrero Negro, could threaten their health. Laguna San Ignacio is also the focus of the largest biosphere reserve in Latin America, the Vizcaino Desert Biosphere Reserve. This reserve is the only home to the small and endangered population of Peninsular pronghorn antelope, the largest population of North American bighorn sheep, and hundreds of thousands of migratory water birds. Environmentalists point out that a sudden influx of factory workers, along with road building, water use, and pollution, will threaten the delicate desert ecosystems, in addition to sea life and the existing fishery and tourism economies. Notably, ESSA proposed the new salt facility only a month after the gray whale was removed from the Endangered Species List in 1994. The proposal was initially blocked by Mexico's environment ministry. ESSA appealed that decision, though, and the project is currently undergoing an environmental impact review. Environmentalists point out that this is only one of many current cases worldwide in which governments are considering industrial development in areas recently declared protected and ecologically valuable. Approval of the Laguna San Ignacio project could be a dangerous precedent. Results of the environmental review should be released in the summer of 1999.       Gray Whale. To read more, see Environmental Science, A Global Concern, Cunningham and Saigo, 5th ed. Endangered species protection: pages 283-89 Biosphere reserves: pages 325-29 Environmental Science, Enger and Smith, 6th ed. Whale protection: page 217 For further information, see these related web sites: Natural Resources Defense Council reports on salt plant and whale activity Oceanographic data on Laguna San Ignacio from Scripps Institute Back to Map Page feedback form | permissions | international | locate your campus rep | request a review copy digital solutions | publish with us | customer service | mhhe home Copyright ©2001 The McGraw-Hill Companies. Any use is subject to the Terms of Use and Privacy Policy. McGraw-Hill Higher Education is one of the many fine businesses of the The McGraw-Hill Companies.