Acoustic ‘Pingers’ Deployed to Keep Sea Mammals Out of Fishing Nets

Chris Williams has been fishing for thresher shark and swordfish long enough to know that one whale can ruin a day’s work.

A commercial fisherman from Oxnard, Williams, 35, is one of about 80 active drift gill net fishers in Southern California who run the risk of getting in the way of whales and other marine mammals every time they unfurl one of their gargantuan nets.

Not only can the giant marine mammals rip through the nylon nets, thus setting the catch free, they can become entangled and drown.

No matter how it unfolds, it can become a great loss.

But now, encouraged by the federal government, Williams and other fishers are experimenting with a $40 device that emits a high-pitched sound to repel whales, dolphins and other federally protected sea creatures from harm’s way.

It’s called an acoustical “pinger,” and since August 1996 the National Marine Fisheries Service has been studying how effective it is at shooing whales away from nets.

Preliminary results indicate that the pingers work, driving away three out of four whales.

“Everyone was blown away by the results,” said Chuck Janisse, co-director of the Ventura-based Federation of Independent Seafood Harvesters. “Statistically, the reduction is amazing.”

The bright orange pingers look like oversize hot dogs. They are 6 1/2 inches tall and emit an annoying beep that travels at least 300 feet in water.

Victoria Cornish, a fishery biologist with the national fisheries service, said the pingers produce a wall of sound that seems to be a powerful deterrent.

In a test on the East Coast, pingers also proved effective in keeping porpoises from becoming entangled in drift nets. The 1994 experiment was so successful that the national fisheries service lifted a ban on drift gill net fishing, provided that the nets are equipped with pingers.

As a result of that study, the national fisheries service convened the Pacific Cetacean Take Reduction Team--made up of fishers, environmentalists and government officials. The team’s mission: conduct a similar study in the open ocean drift gill net fishery on the West Coast, where the gear of choice is the 6,000-foot-long net.

California’s swordfish and thresher shark fishers usually work far offshore, up to 200 miles out to sea for a week at a time. Their nets are generally one nautical mile long and have a mesh size of 18 to 22 inches.

Their nets are towed behind boats and suspended 24 to 75 feet underwater, unlike the practice of foreign fishing fleets, which use 9,000-foot-long gill nets that drift on the surface, where marine mammals and sea birds are abundant.

Use of all gill nets is prohibited within three miles of the California mainland.

About 20 of the nearly 80 active swordfish and thresher shark fishers from Morro Bay to San Diego participated in the first year of the West Coast pinger study, which began in August 1996.

Each net was equipped with 21 pingers across the top and 20 across the bottom, Janisse said.

Government researchers are continuing the study. But the first year’s results showed that pingers reduced the number of whales and other marine mammals caught in the nets by 75%.

“This development indicates that we are going to meet the mandates of the Marine Mammal Protection Act,” Janisse said.

Based on these initial findings, pingers will be mandatory on all shark and swordfish gill net boats in the 1997-98 fishing season, which begins in October and runs through early next year. The season happens to coincide with the gray whale migration along the West Coast.

Williams, the fisherman from Oxnard, said he has set his nets more than 1,000 times in the decade he has caught sharks and swordfish. He said the $1,600 it cost to outfit his boat with pingers is a small price to pay when his livelihood is at stake.

“If it helps, I’m all for it,” he said. “Nobody wants to catch a whale. It totally rips your net apart. And it’s dangerous. Those are big animals.”

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Swordfish have been an important catch off the Southern California coast since the turn of the century. In the early 1900s, harpooners set sail every summer and fall, with their catch peaking in 1978 at 2.6 million pounds.

By that time, some people were already experimenting with more efficient ways to bring fish to market, including the use of drift nets at night to land thresher shark.

They found that their nets caught a lucrative bonus: swordfish. In 1979, legislators approved the incidental catch of swordfish.

And in 1982, the state Legislature decided to limit the permits for catching swordfish with drift gill nets to a total of 200 boats.

Most swordfish harpooners switched to the drift gill nets, a move that ensured a consistent catch, said Diane Pleshner, manager of the Santa Barbara-based California Seafood Council.

“No other fishing tool provides a consistency of supply,” she said. “The nets are more efficient insofar as they can be size-selective.”

The nylon nets catch the larger or mature swordfish or shark, while allowing the smaller fish to pass through, she said.

Pleshner applauded the use of pingers as a way to assure consumers that the threat to protected marine mammals has been reduced.

The pingers are manufactured by the Seacom Division of St. Charles, Ill.-based Dukane Corp., which also makes underwater acoustic locating beacons used in flight data recorders--the so-called black boxes--in commercial and military aircraft.

The pinger was developed from the research of Jon Lien, a marine mammal behaviorist at Memorial University of Newfoundland, Canada.

Lien used an eardrum from the carcass of a juvenile whale to determine the sound that would catch a whale’s attention. That led to underwater alarms in 1994 that kept humpback whales from becoming entangled in cod traps in the North Atlantic.

Some fishers say they are willing to go to almost any length to stay in business. Outfitting a net is a small price to pay, they say.

“The potential for good far outweighs anything else,” said Harold “Lynn” Stephey, 61, of Cambria in San Luis Obispo County. “It really doesn’t matter what the cost is.”

Stephey has been fishing for 30 years. Depending on the season, he’s either bringing in albacore, or swordfish and thresher shark.

Buying pingers, he said, is just one of many prices he pays for being a one-man business. “It’s a fact of life,” he said.