here's a thumb-size patch of pink skin
on the top of a leatherback turtle's otherwise
dark-skinned head; it houses
light-sensing equipment that, combined with
the turtle's ability to detect the earth's magnetic
field, may function as a built-in global
positioning system. A turtle tagged with a
tracking device was once observed beelining
from Canada to western Africa across 3,000
miles of open ocean, never veering from its
Carl Safina, a scientist turned writer and conservationist, was fishing with his Uncles Sal and Tony just outside New York Harbor when he saw a leatherback turtle for the first time. To a boy of 14, it appeared as if a Volkswagen were surfacing. The line, baited for bluefin tuna, had ensnared the great sea beast as it glided along, perhaps on its way from the breeding grounds of the Caribbean Sea to the grand oceanic buffet off Newfoundland.
Sea turtles have been swimming along this way for what seems like forever. They laid their eggs on beaches populated by dinosaurs, and when a meteorite six miles in diameter slammed into the Yucatán Peninsula, obliterating Tyrannosaurus rex and most life on earth, sea turtles were among the few species that survived. "For hundreds of millions of years they swam in a world without people, and in the peopled world they remain unaccustomed and too often unaccommodated. It could not be said of us that we are accustomed to a world without turtles," Safina writes. "Yet now, through the darker side of our human genius, we can envision that day coming."
Over the course of several years, Safina stalked these prehistoric creatures -- silently observing egg-laying females on moonlit beaches, capturing and tagging migrating giants in the open ocean, patrolling prime nesting beaches from the air -- and he recorded his journey in Voyage of the Turtle: In Pursuit of the Earth's Last Dinosaur. His account, filled with prose that is often graceful but at times lapses into purple, weaves science and history into a chronicle of his adventures with the people who know, or seek to know, turtles best.
Among them are Kirt Rusenko, "the turtle's ambassador to landlords" in Boca Raton, Florida, who protects light-sensitive hatchlings by monitoring compliance with lights-out ordinances on the beachfront, and Sally Murphy, a North Carolina biologist who braved death threats in her crusade for laws requiring turtle escape hatches in shrimp nets. Their stories, Safina believes, reveal the "brighter side" of our vision for the future that could "correct our foolishness."
But other stories, brave and wise as their central characters may be, are less uplifting. Consider Llew Ehrhart, an emeritus professor of biology at the University of Central Florida, whose studies of nesting turtles foretell disaster. Ehrhart has discovered that as sea-surface temperatures rise, turtles nest earlier in the season. Eggs that incubate at cooler temperatures generally produce males, while those that incubate at warmer temperatures produce females. But at really warm temperatures, eggs produce females with multiple deformities, or the eggs just don't hatch at all. "If the sand gets hotter, or turtles nest earlier but the sand remains cool, that would affect the male-female ratio," Ehrhart explains to Safina. An unbalanced male-to-female ratio could, in turn, threaten the Atlantic sea turtle population. So to save turtles, we may have to solve global warming first.
As daunting as that task may seem, other forces -- poverty, overpopulation, dwindling resources -- pose an even greater challenge to the turtle's survival. We can pass laws that regulate the kind of nets American shrimpers tow and the type of hook American long-liners bait. We can make it illegal to sell turtle eggs in American markets. We can tell condo dwellers to close their shades during nesting season on American beaches. And we can ask developing nations to abide by international conservation and trade laws. But it's difficult enforcing these laws at home, let alone in countries whose impoverished citizens must turn to the sea to ward off starvation. Buying turtle-safe nets and hooks is expensive; eating turtle eggs
harvested from the beach is free.
Mexico's Pacific Coast was once the annual birthplace of
thousands of sea turtles. Now roads give people from overcrowded inland cities access to remote coastal areas, and turtle eggs disappear from their nests. Laura Sarti, a local biologist, tells Safina: "Twenty-five years ago we thought we would save the world by working with turtles on the beach. Now I believe the key to conservation is eliminating the causes of poverty."
Guided by their ancient internal navigational systems, sea turtles swim across entire ocean basins, through billions of fishing hooks, to lay their eggs into the buckets of poachers. We can protect them at home, but sea turtles will remain peripatetic world travelers -- and survivors, or so we hope.
-- Laura Wright