Eye to eye with orca in the Sea of Cortez - Mexico - includes ecotourist's guide to the Sea of Cortez

Sunset, March, 1993 by Matthew Jaffe

On our long push toward the islands of the Midriff region, huge manta rays jump out of the sea, sending tall sprays of water into the air. Breathtaking at first, the mantas' leaps eventually become routine, and even frustrating for whale-watchers who mistake the distant splashes for spouts. Suddenly, a great school of common dolphins surrounds the Don Jose, with 10 or so jostling for the best position along the bow. When we come upon a pod of pilot whales, the dolphin's 20-foot-long relatives, the boat's captain barely slows down, mindful of the many miles we have to cover by morning.

After sailing all night, we awake to a surreal sight at dawn: a snow-covered mountain with a thick forest of pine trees. The mountain, it turns out, is actually the volcanic outcrop of Isla San Pedro Martir; the pines, a cluster of cardon cactus. Successive generations of the blue-footed and brown boobies that crowd the crags with their nests each did their part for the island's snow, which is a white crust of guano.

As we approach, the shy boobies hold their ground, whistling at the camera-toting tourists while keeping a watchful eye on the common gulls that wait for openings to plunder unguarded eggs or even carry away young chicks. The Sea of Cortez can easily cure a tendency to blindly idealize nature: as much as this area is about life, it's also about death.

Nearby Isla Raza is considerably newer than most of the sea's islands, a tiny volcanic outcrop no more than 11,000 years old. Cold upwellings make this area one of the sea's most productive. In these waters, schools of sardines converge to provide a readily available food source for the 300,000 Heermann's gulls and 50,000 elegant and royal terns that nest on the island.

Their clamor overwhelms us when our panga pilot, Luis, kills the engine as we draw near. The calls of individual birds merge into a single cry of urgency and excitement, exaggerated by the constant swirl of airborne gulls and terns.

Onshore, a fuzzy gull chick stands in front of a rock with a painted message: "Robar huevos aqui es un crimen" ("Robbing eggs here is a crime"). Anglers and others looking for food once plundered Raza's nests, and, with 95 percent of the world's population of Heermann's gulls breeding here, the egg robbers threatened the bird with extinction.

Set aside by Mexico as a bird refuge, Raza represents one of the success stories in the Sea of Cortez. But guarding the island is easier than preserving the ecosystem that made this seabird convention possible.

Dietary studies of Raza's seabirds by biologist Enriqueta Velarde of the University of Mexico reveal a disturbing trend. A two-year analysis showed that sardines made up 88 percent of the birds' diet; four years later, they made up only 10 percent. This occurred at the same time that the Mexican fleet sardine catch rose by 50 percent a year to make up 30 percent of the total national take of all types of fish. Though the birds have switched to eating anchovies, Velarde and others express concern over the long-term effects of the sardine loss.