Tag it and track it

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On a sunny mid-October afternoon, Stanford University graduate student Chris Perle was out at sea, searching for a four-inch metallic gray object, resembling a small microphone with an antenna, adrift in the Pacific Ocean.

One day earlier, the device, known as a “pop-up satellite archival tag,” had popped off the fin of a female great white shark after 300 days of collecting data as the creature crisscrossed the ocean.

Despite having its rough coordinates and $7,000 worth of monitoring equipment in hand, Perle and his colleagues could not find the tag, so he called back to marine sciences professor Barbara Block at Stanford’s Hopkins Marine Station.

Block checked her computer, rattled off a few new coordinates to Perle via cell phone, and then explained why she and her researchers were going to such lengths to recover “a small thing in a big ocean.”

“We’re throwing everything we’ve got at this because it’s very important we find this tag” in order not to lose months of valuable data, Block said.

Block is one of several California researchers who devotes much of her work to the Tagging of Pacific Pelagics (TOPP) program, a multi-institution project that tracks an array of species across the Pacific.

In just three years, they have attached tags to 2,000 predators of 23 different species, including seals, whales, sea birds, blue fin and yellow fin tuna and at least four types of sharks.

Some devices are programmed to pop free after a set number of days, while others transmit data to a satellite whenever the creature surfaces so that researchers can know its position in real time.

The work can be grueling: It took Perle almost a week to retrieve the tag that had popped off the great white shark in October, in part because it drifted 25 miles down the coast over the course of a week, coming near shore before floating out again. In the process, he got a serious case of poison oak that landed him in the emergency room.

Their work, along with a slew of other technology-driven studies by others, is transforming the way scientists, policy makers and conservationists understand the sea.

Across the globe, scientists are now deciphering the ocean in an array of new ways.

Felicia Coleman, who directs Florida State University’s Coastal and Marine Laboratory, implants “acoustic tags” in grouper in the Gulf of Mexico.

The devices make specific sounds picked up by a receiver within a quarter-mile, so that she and her colleagues can track how individual male fish maintain their territory while females move in and out as they fatten up for breeding.

Peter Wiebe, a biologist at the Woods Hole Oceanographic Institution, analyzes the DNA of zooplankton while at sea to study how these creatures at the base of the ocean food web are faring.

And Patrick N. Halpin, a Duke University ecologist, is crunching data collected by government officials, scientists and fishermen to generate computer maps that will help ships avoid striking whales in the North Atlantic.

Duke was the first major academic institution in the nation to endow a professor of marine conservation technology, a post it aims to fill next year.

“Things that have been never been known before are not only known, but known with a high degree of precision,” said Stanford University marine biologist Stephen Palumbi.

In 2003, Palumbi used DNA sequencing to deduce that before commercial whaling began, several types of whales were three-to-10 times more abundant than anyone had thought.

“It’s an incredibly powerful source of information for conservation,” he said. “These technologies allow us to nail it.”