The sight was a cause for celebration: a juvenile humpback whale stationed near the entrance of New York Harbor was yet another sign that the waters surrounding New York City are vastly cleaner than they were a decade ago. But recreational boaters quickly noticed that something was wrong.
The whale’s tail was entangled in a thatch of fishing gear — rope, netting, buoys, steel cables — that seemed to be anchoring the whale to the seafloor.
What happened next was “inspiring, to say the least,” said Robert DiGiovanni Jr., a chief scientist at the Atlantic Marine Conservation Society.
Experts flew to New York, determined to save the humpback. The Army Corps of Engineers sent a ship to assist them. It was a particularly difficult rescue: The crew ended up ditching their specialized tools and instead turned to bolt cutters and hacksaws.
In all, it took three days in late July to free the immobilized whale.
As recently as nine years ago, the nonprofit group Gotham Whale counted the whales off New York City and recorded just five. That number jumped to 377 in 2019, leading some scientists to conclude that the whales’ prey, and then the whales, had returned because of healthier waters.
But the influx of whales has also meant that the number of them injured or killed by entanglements, strandings and ship strikes is on the rise.
Because all marine mammals are federally protected species, government agencies, such as the National Oceanic and Atmospheric Administration and the New York Department of Environmental Conservation, are obligated to do everything they can to protect them. But many agencies are struggling to aid increasing numbers of the whales, and they sometimes pay nonprofits groups like the Coastal Science Society to assist in the efforts.
“Ten years ago, we’d have one entanglement sighting off New York every four or five years,” said Scott Landry, the society’s director of marine animal entanglement response. “Now it’s every other year.”
When Mr. Landry got a call about the entangled whale near the harbor, he jumped into action: The whale had been identified by the society’s researchers as the 4-year-old calf of Nile, whom he had helped free off the Massachusetts coast in 2001. (Every whale has unique markings on its flukes, the fins that make up its tail, so researchers can track a creature’s movements using photographs provided by whale watchers.)
Less than 24 hours later, Mr. Landry, two other rescuers and nearly 900 pounds of disentanglement equipment were on a flight from Cape Cod to New York.
The rescue got off to a slow start. The calf’s tail was weighed down about 20 feet below the water’s surface, so crews could barely see the fishing gear that they were trying to handle. Their knives couldn’t cut through some of the material.
The rescuers are not allowed to submerge themselves because the risk of becoming entangled is too great. Instead, they work from small, inflatable boats that let them get within feet of a whale.
“We have never once given up on a whale, but there were a few moments during the first and second days that we were starting to feel like we had no tools at our disposal to get this particular entanglement done,” Mr. Landry said. “People were using some colorful language.”
No one knows exactly why whales are becoming more abundant in the waters off New York, but researchers like Melinda Rekdahl, a marine conservation scientist for the Wildlife Conservation Society, cite more hospitable waters and increased regulation of the Atlantic Ocean’s menhaden fisheries.
Menhaden are small, oily fish packed with omega-3 fatty acids that the whales feed on. Over the past decade, the state has worked to protect them from overfishing and to reduce pollution in their habitat. That has helped attract not only whales, but also striped bass, dolphins, sharks, seals, seabirds and other marine life.
But coastal waters can be a perilous place for whales: Cargo ships, fishing vessels and recreational watercraft off New York pose constant threats.
“Unfortunately, as whale sightings increase in New York City waters, there also seems to have been an increase in human-wildlife conflict,” Dr. Rekdahl said. “This all indicates the need for greater awareness and management of whale populations.”
Since 2013, the state has put $5 million toward research on how whales navigate coastal waters. Still, whales hit by boats or tangled in debris have been washing ashore in increasing numbers. According to the state’s Environmental Conservation Department, at least 54 large whales have become stranded along the coast since 2017. Most were dead in the water, but some were alive and in need of rescue.
That same year, the department began conducting aerial and acoustic surveys in hopes of improving its understanding of how humpback whales, fin whales, blue whales and other large cetaceans use the coastal waters. Reducing the amount of vertical lines from fishing gear and asking ships to slow down could also help keep whales safe, conservation advocates have said.
“The cleaner we make it here, the more we’re going to have to more carefully manage this resource,” said Basil Seggos, commissioner of the Environmental Conservation Department, referring to the whale population. “You cannot do that unless you can perform accurate science and then communicate that out.”
New York State does not have its own whale disentanglement team, so nonprofits like the Coastal Science Society and the Atlantic Marine Conservation Society often step in to help, as was the case with the recent rescue of the 4-year-old calf.
By the third morning of the rescue, the team needed a new plan. A ship provided by Monmouth University’s Urban Coast Institute, in New Jersey, lowered a grappling hook toward the seafloor to grab the gear weighing the calf down. The hook was then handed off to a larger boat provided by the Army Corps of Engineers, which had a crane onboard that was powerful enough to pull the gear to the surface.
The crew then realized that there was a half-inch piece of steel cable wrapped around the whale’s flukes. That was when the bolt cutters and hacksaws came in: Rescuers cut through the cable, and within minutes the whale was free.
In all, the team removed a staggering 4,000 pounds of gear from the whale, which had deep lacerations on its tail because of the entanglement.
Mr. Landry said the whale had likely become became entangled after swimming into a trawl net, which fishers drag behind their boat to catch large schools of fish. Still, Bonnie Brady, the executive director of the Long Island Commercial Fishing Association, said conflicts between fishing vessels and whales were rare in New York waters.
The rescuers were optimistic that the calf — which had yet to be named — would make a full recovery. It was recently spotted by whale watchers off Montauk, on Long Island.