Whales at the Jersey Shore are repeat visitors, yet some don’t survive their encounters with humans

It’s no secret that a sizable chunk of Philadelphia goes to the Jersey Shore year after year. Turns out humpback whales do it, too — sometimes staying for months at a time, according to a new study of the massive creatures.

Researchers crisscrossed the ocean with high-powered cameras for seven years, tracking the whales to learn how they might be protected from harm.

Humpbacks are in the seventh year of an “unusual mortality event” along the Atlantic Coast, the U.S. government says. In some cases, they have died from impact with a shipping vessel.

The busy waters off New Jersey and New York are a particular trouble spot, said Rutgers University ecologist Danielle M. Brown, lead author of the new study.

“This is a high-risk area,” she said. “It’s important to know how long these whales are staying here and if they return year after year to this busy area, because their level of exposure is increased.”

While the reasons for the surge in whale sightings are not entirely clear, a leading theory is the abundance of fish they like to eat, called menhaden, said Brown, a Rutgers doctoral candidate who also works at a New York-based nonprofit called Gotham Whale.

Equipped with zoom lenses aboard Gotham’s 29-passenger whale-watching boat, the American Princess, she and her colleagues tracked humpbacks by looking at distinctive markings on their skin — primarily on the undersides of their tail fins, called flukes.

“It’s similar to a fingerprint in humans,” she said. “It’s unique to each humpback whale.”

The team canvassed the ocean during the spring-through-fall feeding seasons of 2012 through 2018, from Manasquan Inlet at the northern edge of Ocean County out to Fire Island in New York. They also welcomed photos from the public, provided they included a date and GPS location.

All told, the group identified 101 humpbacks in the study, 59 of which were seen on multiple occasions. Most were juveniles measuring 25 to 30 feet in length (adults can grow as large as 60 feet).

The researchers then compared this “catalog” of whales with those from other whale-watching groups up and down the coast and found that dozens of the same humpbacks were feeding there, too, including 15 in the waters off Cape May.

Matching the whales from photo to photo requires a keen eye, said coauthor Melissa Laurino, who helped identify the 15 Cape May whales in her job as research director at Cape May Whale Watch & Research Center.

“It is fun to watch whales and dolphins all season long, but a large part of the research is sitting in front a computer screen,” she said.

These Western Atlantic humpbacks generally spend the winter breeding season in the Caribbean, then migrate northward in the spring to eat mackerel and herring — primarily in the Gulf of Maine and the waters of eastern Canada and Greenland.

But to judge from increased sightings in the last decade, more humpbacks seem to be pulling up short in New Jersey and New York, where their main food source is menhaden. These fish, sometimes called bunker or pogy, also are sought by the fishing industry, which sells them as bait and for use in fertilizer, pet food, and fish-oil supplements.

For now, the ocean seems to have enough menhaden for whales and humans alike, after regulators started to impose catch limits a decade ago (though some in the fishing industry have argued that the quotas were unnecessary).

Yet with the apparent increase in humpbacks off New Jersey, New York, and other Atlantic states, more whales are dying. Over the last 6½ years, 161 humpbacks have become stranded along the East Coast, including 57 in New Jersey, New York, and Delaware, the National Oceanic and Atmospheric Administration says. The whales’ fate is not known in every case, but most do not survive.

In New Jersey and New York, shipping vessels are one of the primary risks for humpbacks, said Brown, the study author. Recreational vessels also can be a threat, if they approach too closely and disrupt the mammals’ feeding, she said. Boats should stay at least 100 feet away from humpbacks, farther if multiple boats are in the area.

Determining the cause of a whale death can be tricky, as with one humpback that was found July 10 at Wildwood Crest, stuck under a dock, said Bob Schoelkopf, director of the nonprofit Marine Mammal Stranding Center in Brigantine. It had been dead for several weeks and was too badly decomposed to tell how it had died.

Workers waited for high tide, then towed the carcass to a remote part of the bay and tied it to some unused pilings, said Schoelkopf, a coauthor of Brown’s study.

“That’s where it’ll stay till it turns to bone,” he said.

Fishing vessels do not pose a big threat to humpbacks in this region, though close encounters can occur by accident, Brown said. In June 2020, a humpback leaped from the waters off Seaside Park and struck a fishing boat with a loud thud. Its two passengers were thrown into the water but escaped unharmed.

In July 2021, a humpback became trapped in fishing gear in New York’s Ambrose Channel, but rescue workers were able disentangle it.

With continued vigilance, Brown and her colleagues aim to keep the large mammals from harm. Since the end of the seven-year period covered by the study in the Journal of the Marine Biological Association of the United Kingdom, they’ve kept going out on the water with their zoom lenses.

As of this summer, they’ve added 156 more to the area’s humpback catalog, for a total of 257.