Dangers Await Gray Whales on Return to Winter Home
By LARRY ROHTER
Published: December 20, 1988
GUERRERO NEGRO, Mexico— WITH any luck, the two gray whales that won world sympathy in October when they were trapped in ice off Point Barrow, Alaska, will soon reach their winter home here. But when the giant mammals arrive, they and others of their species who spawn in Baja California each year will confront another set of potential dangers.
''This used to be an isolated part of the country,'' said Dr. Bernardo Villa, director of the mammalogy laboratory of the Biology Institute of the National Autonomous University of Mexico, a leading Mexican expert on whales. ''But human activity in every sense of the word is now being felt here, and so the entire ecosystem is being affected.''
The gray whale, which grows as long as 50 feet and as heavy as 35 tons, is one of the great success stories of modern conservation. Hunted almost to extinction in the 19th century by whaling ships such as the Black Warrior, which foundered here in 1858 and gave this dusty, sun-baked coastal town its name, the gray whale belatedly became the object of international protection efforts. The population has grown in recent years to an estimated 18,000 animals. Journey to Baja California
Luis Fleischer, director of the Mexican Government's National Program for the Investigation and Conservation of Marine Mammals, estimated that more than 1,500 gray whales take winter refuge in the warm waters of lagoons along the southwestern coast of the 800-mile long Baja California peninsula. Typically, an adult female will arrive in December, give birth to its young, mate and head back north to Alaska in late March.
''These waters have tremendous importance in the reproduction of the gray whale and the care of newborns,'' he said aboard a small boat plowing through the waters of Scammon's Lagoon as the giant whales noisily leaped, splashed and spouted about it. ''But they are also important for adults who want to sleep and rest.''
Responding to international concerns about the long-term welfare of the whales, the Mexican Government earlier this year established a 7.2-million acre wildlife reserve here, said to be the largest in the world. In addition to coastal and inland waters, mountain and desert areas were included in the reserve, and an internationl research center for scientists to carry out permanent studies is also planned.
In announcing the reserve, the Ministry of Urban Development and Ecology said it would offer ''integrated protection to the whale and the ecosystem in which it lives.'' Scientists and ecology groups have largely praised the initiative, but they also say more must be done to protect marine and land animals in the reserve.
''For various reasons, we have not had the opportunity to carry out a strict vigilance,'' Dr. Villa said. ''We lack the airplanes, helicopters and boats we need if we are really to protect these species.''
In addition, Dr. Villa and other scientists recommend that dredging be employed to deepen the waters of lagoons, further down the coast and now in disuse, that whales might find attractive as winter grounds. Aerial and aquatic surveys done here seem to indicate the gray whale population may be leveling off, and the scientists believe that is because existing winter refuges are now supporting a population close to their maximum capacity.
On their own, gray whales, a species that prefers shallower coastal waters to the high seas, have in recent years rounded the southern tip of the peninsula and penetrated the Gulf of California.
The greatest source of concern to scientists and ecologists, however, is the continued presence here of the largest open salt mine in the world. Operated by Exportadora de Sal, known as ESSA, the large industrial complex exports 5.5 million tons of salt a year, and is planning to expand. Threats to Whales' Habitat
In extracting, processing and shipping the salt, ESSA uses nearly five million gallons of diesel oil a year, and late in 1984 a million gallons of the fuel were somehow spilled into a marshy area near a lagoon the whales favor. About 400,000 gallons were recovered, but because of ''the difficulty of extraction, its high cost and the determination the underground stain could not leak into the lagoon,'' as a government document puts it, the operation was suspended.
According to the same study, the construction of docks and canals in the lagoons here ''has resulted in the modification and degradation of the habitat.'' Human population growth and the dumping of solid waste were found to have the same effect.
In addition, silting has occurred at the mouth of Guerrero Negro Lagoon, making the entrance both narrower and shallower and discouraging the whales from passing through. The phenomenon is natural, rather than man-made, having occurred after ESSA moved its port facilities to nearby Scammon's Lagoon and ended dredging operations that had kept the smaller lagoon open.
''Water levels have dropped in some places, and strata are being changed,'' Dr. Villa said. ''The gray whale needs waters that are at least 25 feet deep, so it is important to prevent bottoms and shallows from filling with sand.''