Conservation & Science

Reeling in a major cause of whale entanglement

Calder Deyerle is on a conference call. But while other participants sit in office chairs, Deyerle is miles out at sea on his 28-foot boat. Freshly caught fish, in a bucket at his feet, are flopping loudly enough to be heard on the call.

Calder_boat
Fisherman Calder Deyerle fishes for rockfish off the Big Sur coast. Photo by Monterey Bay Aquarium/Presley Adamson

During crab season, Deyerle says, he works what feels like 24 hours a day—going home only to shower, eat and see his family. Even when he watches TV, he keeps his hands busy mending gear. Serving on the Dungeness Crab Fishing Gear Working Group, which led to the conference call, is what he calls one of his “extracurricular activities.”

But it serves a practical purpose: preserving a fishery, and a way of life, that’s been in his family for generations. And it’s helping protect one of the ocean’s most magnificent animals, too.

A migration menace

In recent years, crabbing gear has entangled whales, mostly humpbacks, with alarming frequency. In 2016 there were 71 reported entanglements along the U.S. West Coast—the most since the federal government began keeping records in ’82. Twenty-two of those were confirmed to be related to the Dungeness crab fishery.
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MBARI’s new ear on the sounds of the ocean

Researchers at the Monterey Bay Aquarium Research Institute (MBARI) have learned a lot about Monterey Bay using robotic submersibles to look deep below the bay’s surface. Now they can listen to the bay as well, using an ultra-sensitive underwater microphone. Sounds recorded by this hydrophone have already provided surprising information, including evidence that beaked whales, though rarely seen, are common in the outer bay.

MBARI placed a deep-sea hydrophone on the seafloor using a remotely operated vehicle. The green cable carries power to the hydrophone and data back to shore. Photo courtesy MBARI
MBARI placed a deep-sea hydrophone on the seafloor using a remotely operated vehicle. The green cable carries power to the hydrophone and data back to shore. Photo courtesy MBARI

In July 2015, MBARI researchers installed a broadband hydrophone on Smooth Ridge, about 30 kilometers (18 miles) from shore and 900 meters (3,000 feet) below the sea surface. Since that time, signals from the hydrophone have been relayed back to shore in real time, 24 hours a day, using MBARI’s cabled ocean observatory, the Monterey Accelerated Research System (MARS).

The new hydrophone doesn’t look very impressive. It’s just a metal cylinder about two inches in diameter, mounted on a metal tripod on the muddy seafloor. But it is extremely sensitive and can pick up a vast range of sounds, including those too low and too high for humans to hear.

A spectrum of sound

“We’re trying to characterize the soundscape of Monterey Bay,” says John Ryan, the biological oceanographer in charge of the project. “This means looking at the whole spectrum of sounds that we record and identifying all of the phenomena they represent. This includes biological sounds such as vocalizations of marine mammals, the sounds of physical processes such as wind and rain, and the sounds of human activities.”

MBARI’s deep-sea hydrophone is located on Smooth Ridge in the Monterey Canyon, about 30 kilometers (18 miles) from shore. Base image: Google Earth
MBARI’s deep-sea hydrophone is located on Smooth Ridge in the Monterey Canyon, about 30 kilometers (18 miles) from shore. Base image: Google Earth

Most adults (at least those who haven’t attended too many rock concerts) can hear sounds from about 20 Hertz (the low rumble of an earthquake) up to 16,000 Hertz (the high-pitched buzzing of a mosquito). The new hydrophone can pick up sounds ranging from 10 Hertz to 128,000 Hertz.

During a recent meeting with underwater acoustics experts, Ryan played a few of the distinctive sounds recorded with the hydrophone.

Here’s a recording of dolphins:

 

And here’s one of humpbacks:

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Paul Michel: A special place on Earth

Through September 2, Monterey Bay Aquarium and Monterey Bay National Marine Sanctuary will host Big Blue Live – an unprecedented series of live natural history broadcasts from PBS and the BBC. Big Blue Live highlights the remarkable marine life that gathers in Monterey Bay each summer, and celebrates an ocean conservation success story of global significance. We’re publishing guest commentaries about conservation efforts that contribute to the health of the bay and our ocean planet. This is from Sanctuary Superintendent Paul Michel.

Recent NASA pictures of Earth remind us that we indeed inhabit a blue planet – that most of our planet is covered by the ocean. In fact, it is the “big blue” that makes ours a habitable place to live, regulating temperature and weather, and providing more than half of the world’s oxygen. So it’s fitting that Big Blue Live comes here to showcase one of the most spectacular ocean environments on Earth.

Paul Michel
Superintendent Paul Michel

The ocean is home to amazing creatures, from microscopic to gigantic – seemingly endless varieties of the shelled, scaled, skinned, feathered and furred. But, when you consider all the marine ecosystems, all the coastlines around the continents, even all the aggregations and migrations of sea life, Monterey Bay National Marine Sanctuary stands out as one of the most spectacular: beautiful, rich, and diverse. As a result, this Sanctuary offers some of the best marine wildlife watching in the world, and is often described as the “Serengeti of the Sea”.

What makes this place so special is what happens out of sight and behind the curtain of waves. Seasonal winds drive cold water to the surface from great depths. These waters are rich in nutrients, which fuel the growth of phytoplankton – the basis for the Sanctuary’s rich marine food web. This productivity invites animals from all corners of the Pacific to come and dine (and live year-round) at the “Monterey Bay Café”!

Anchovies abound in Monterey Bay, from open water to kelp forests close to shore. Photo: Randy Wilder
Anchovies abound in Monterey Bay, from open water to kelp forests close to shore. Photo: Randy Wilder

And what’s on the menu?  There are some tasty entrees: krill, squid, sardines, anchovies and even jellyfish (if you’re a leatherback sea turtle!). All told, 34 species of marine mammals and more than 180 species of seabirds and shorebirds come to the table. Monterey Bay and Greater Farallones sanctuaries together contain the largest concentration of white sharks on the west coast.

We humans feed here as well.  Since 1992, the sanctuary’s productive ecosystem has supported the harvest of more than a billion pounds of sardines, anchovies and squid. Last year was the greatest landing (by weight) of any of these prey species in the past 15 years, with 90 million pounds of squid alone landed at local ports.

Along with krill (which are not fished) these are the most significant prey in the ecosystem, upon which many species from whales to salmon to seabirds to halibut rely.

West Coast sanctuaries

Monterey Bay and surrounding waters are also special because of the protection they’ve received. Designated in 1992, Monterey Bay National Marine Sanctuary is a federally protected marine area, an underwater equivalent to the grandest of America’s national parks. Stretching from Marin County to Cambria, the Sanctuary encompasses a shoreline length of 276 miles (more than one-quarter of the California coast) and 4,602 square nautical miles of ocean. The Sanctuary plays an important role in protecting marine life and ecosystems of the Bay, as well as conducting scientific study and raising awareness about what a special place it is.

Overall, the marine habitats and living resources in Monterey Bay National Marine Sanctuary are in excellent condition, according to our latest evaluation of current trends and pressures. Populations of humpback whales, blue whales, gray whales, elephant seals, sea otters and numerous fish species are stable or slightly increasing.

Elephant seals at the growing colony at Piedras Blancas, on the Big Sur coast.
Elephant seals have established a growing colony at Piedras Blancas, on the Big Sur coast.

As one example, elephant seal births in the Sanctuary have more than tripled since 1992. In fact, there were no births at Piedras Blancas, near the south end of the Sanctuary, in 1992. Today, a large well-established colony exists, producing thousands of births. For another, best estimates put the Eastern Pacific population of gray whales at a healthy 20,990 individuals at the end of 2014. Gray whales make one of the longest annual migrations of any mammal: they travel about 10,000 miles (16,000 km) round trip!

Over the last two years, humpback whales (about 1,875 individuals in the West Coast stock) have been seen close to shore and very accessible to the whale-watching public as the whales feed on anchovies and krill.  Monterey Bay National Marine Sanctuary led the way in protecting krill as a critical component of the ocean food web. This is now a regulation for the entire west coast of the U.S.

To see animals like these in the wild is truly the experience of a lifetime. Because they’re ocean dwellers, and often below the surface, most of us rarely get the chance. Big Blue Live will deliver  these experiences to people across the planet in a very engaging and special way.

You don’t want to miss it!

Learn more about Monterey Bay National Marine Sanctuary.

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