Rare sighting: sperm whale spotted off the coast of Cape Cod

For the first time in six years, scientists from the New England Aquarium spotted an endangered sperm whale calf about 130 miles southeast of Cape Cod. They were conducting an aerial survey over the Northeast Canyons and Seamounts Marine National Monument.

“We’ve flown 16 surveys out there and this is the first calf we’ve seen, it just shows that it’s not a common occurrence for us,” said Sharon Hsu, a research technician with the Anderson Cabot Center for Ocean Life at the New England Aquarium

The calf was seen swimming with an adult sperm whale. The mammals can weigh up to 45 tons and can measure 52 feet in length. They are the largest of the toothed whales and can be found in ice-free waters throughout the world’s oceans and in the Mediterranean Sea.

The Northeast Canyons and Seamounts Marine National Monument is the US Atlantic’s first monument. It was designated by former president Barack Obama in 2016.

The protected area spans 4,913 square miles of marine ecosystems — about the size of Connecticut — an area of scientific exploration and discovery since the 1970s. It encompasses three underwater canyons that are deeper than the Grand Canyon, four seamounts, and extinct volcanoes that rise higher than any mountain east of the Rockies.

Hsu said that when she and her team of pilots, observers, data-gatherers, and photographers embark on an aerial survey, they are normally in the sky for about five hours and record hundreds of animals. The team flies on six different “survey lines” while they’re in the sky and will divert off course if they spot notable marine life.

“We have sighting cues we look for and we can see species from 1,000 feet,” she said. “If there is anything we are unclear about, we take photographs and review them in the plane to have a better idea of what we’re looking at.”

Prior to whaling, sperm whales may have numbered 1.1 million worldwide, according to the American Cetacean Society. Today, there are an estimated 300,000.

Marine national monuments are designated to protect and conserve ocean ecosystems. When the area south of Cape Cod was named a monument in 2016, the National Oceanic and Atmospheric Administration implemented a seven-year phase-out of existing commercial fishing permits for red crabs and American lobsters. That phase-out ended this September.

Now, commercial fishing is prohibited within the monument, but recreational fishing and scientific research are allowed by permit.

“It will take more surveys for us to know if things have changed because of the protections now that the commercial fishing allowance has been phased out,” Hsu said.

Following the sperm whale calf sighting, the Aquarium submitted public comments and recommendations to US Fish and Wildlife Service and NOAA, the agencies working to draft a management plan for the monument.

The Aquarium recommended that the agencies ensure sustainable funding for public education and outreach about the monument. It’s also calling for more monitoring of activities like shipping and fishing.

“The intended outcome from submitting public comments is to inform the final management plan and in so doing, guide the work of stewarding the monument for the next 15 years,” said Sarah Reiter, director of ocean policy at the New England Aquarium. “The government is currently analyzing the public comments and we hope to see the release of the final plan to the public as soon as possible.”

Maggie Scales can be reached at maggie.scales@globe.com. Follow her @scales_maggie.

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