Sunday, September 05, 2010

Sleek and Deadly: Prowling the Seas: Exploring the Hidden World of Oean Predators by Pamela S. Turner

The bluefin tuna are hunting.

A leatherback sea turtle glides below the bluefin. As she flaps her long front flippers, she looks like a bird flying in slow motion. High above, lost, in the
clouds, a seabird flies on silent wings.

A great white shark swims nearby. Her coal-black eyes roll toward the surface. She is looking for a seal

What do tuna, sea turtles, seabirds, and a great white have in common? All are predators, carnivores who depend upon the sea for their prey and whose lives revolve around the daily quest for food. Few of us realize that most of earth's predators, unlike the familiar wolf, tiger, or anaconda, live not on the land, but in the seas of the world. Vital to the life cycle of the ocean as they are on land, ninety per cent of the ocean's one-time predators, large fish such as sharks and tunas, are gone, and the remnant is struggling to hang on to viable breeding stock numbers.

Pamela Turner's Prowling the Seas: Exploring the Hidden World of Ocean Predators (Walker, 2009) traces the efforts of marine scientists to unlock the secrets of the seas' great predators in a race to keep them swimming and flying in their natural homes.

Turner tells of the tagging of female turtles and their annual race to the Galapagos, the tagging of juvenile tuna which swim an heroic marathon from the coast of California to the coastal waters of Japan where they find their way into a fisherman's catch to become sushi on someone's table. She relates the story of a Kindergartner who finds a strange object in a tidal pool which is turns out to be a great white shark tag with data tracing its bearer from the U.S. Pacific Coast to waters off Hawaii and back again. Scheduled to pop off and relay its data from the sea surface to a space satellite, the tag was apparently dislodged by bites from another shark, where it floated into tidal waters. And finally she tells how a mated pair of tagged shearwater seabirds on an island off New Zealand rode the "westerlies" all the way to the Humboldt Current off the coast of South America; there the pair split, the male heading for Japan while the female flies up the coast to Oregon and back, both returning to the same spot in New Zealand in time for the nesting season.

Turner points out that scientists learn many things from this vital data about ocean predators, but the main "lesson from the blue" is that the web of life is wide and takes its dependent animals to far-flung places, through many territorial waters affected by many wide-ranging forces. The author's thesis is that the ocean is a world-wide phenomenon with no national boundaries, and those that live from it have a fragile existence. More information can help us do what we can to help preserve their role on the seas.

An appendix offers detailed information about the featured animals--leatherneck sea turtles, bluefin tuna, white sharks, and sooty shearwaters--and a list of resources which includes recent books, DVDs, and web sites for students and teachers, including Google Ocean and the Smithsonian Institution.

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