The waters of North Jersey and New York City have become such a large feeding ground for humpback whales that many are staying longer than they used to and returning year after year, a study released Monday by Rutgers University shows.
The number of humpbacks sighted from the Manasquan Inlet north to the lower Hudson River and east to Fire Island has grown significantly in recent years. There were sightings of 101 individual whales from 2012 to 2018. As of Monday, that number had risen to 257 distinct individuals, said Danielle Brown, the study’s lead scientist.
“There is still a lot of ongoing research to determine why they’re here, but certainly we’re seeing the long-term benefits of action taken in the 1970s like the Clean Water Act and the Marine Mammal Protection Act,” said Brown, a Rutgers doctoral candidate and head researcher for the advocacy group Gotham Whale.
In the most comprehensive study of its kind of the region’s waters called the New York Bight, researchers found that more than 58% of whales were seen more than once, either within the same year or between years, with the average length of stay about 38 days.
Luring them into New Jersey’s waters are schools of small bait fish called menhaden or bunker fish, whose numbers have grown in recent years. One theory is that cleaner waters in the region allow plankton to flourish closer to shore, providing a food source to bunker. And humpbacks like nothing more than to breach the ocean’s surface and stuff hundreds of bunker into their mouths.
Although overflows from outdated pipe systems that combine stormwater and sewage are still a big problem in New Jersey, less industrial pollution and better runoff protections have improved the region’s water quality, said Bill Schultz, head of the Raritan Riverkeeper advocacy group.
“The bottom line is when you have cleaner water, you’ll have more food, and that in turn will attract more animals,” he said. “Everything is connected.”
Most of the whales cataloged in the study from 2011 to 2018 were juveniles, less than 5 years old. Comparing images of their unique tail fins, researchers were able to determine that many of the whales were from the Gulf of Maine, and some were from off eastern Canada.
The whales are also swimming in one of the busiest commercial and recreational boating areas in the world, raising fears of strikes. They have become so abundant that whale-watching tours are offered from Rockaway, New York, as well as Belmar, Point Pleasant and Cape May, from mid-spring through autumn, when whale sightings are at their peak.
It’s a stark contrast to mid-century, when the humpback population dwindled after centuries of being hunted, mostly for their blubber to make oil. Humpbacks have been spotted along the Jersey Shore and Long Island for decades, but not to this extent.
“We don’t know if they are returning to an area they once occupied or if this is something completely new,” Brown said. “We do know that they were being hunted up and down the East Coast since the 1600s, mostly in New England, and we do know they are recovering.”
It’s still being determined to what extent the changes in ocean temperatures due to global warming are contributing to the changes in plankton, bunker fish and whales.
Schultz has seen sea turtles, dolphins and even tropical fish come into Raritan Bay from the Atlantic in the past decade. “We’re seeing everything these days,” he said. “Nothing is surprising us anymore.”
The study was a collaboration among Rutgers, the nonprofit group Gotham Whale, the Center for Coastal Studies and 21 other organizations. It was published in the Journal of the Marine Biological Association of the United Kingdom.
