NEW YORK • If you think New York's wildlife is limited to pigeons and squirrels, Dr Howard Rosenbaum, the director of the ocean giants programme at the New York Aquarium on Coney Island, has some surprising news. "In less distance out to sea than the average New Yorker's commute home, there is likely a whale singing at this very moment," the marine biologist said.
At least seven species have been sighted offshore. They include the largest animal that has ever lived, the blue whale, and one of the most endangered creatures on earth, the North Atlantic right whale. There are also humpback, fin, sei, mine and sperm whales. As to why so many whales are passing through New York's waters - and which of them live in the metropolitan area year-round - even whale experts are at something of a loss.
To solve those mysteries, the aquarium's parent organisation, the Wildlife Conservation Society, has partnered with the Woods Hole Oceanographic Institution, the biggest independent ocean research centre in the United States, to conduct the largest-ever survey of New York's whales.
The project began on a research vessel about 35km off Fire Island in thick fog on the night of June 23 without so much as a splash as technicians gently eased a listening buoy into calm waters.
Senior engineer Kris Newhall at EOM Offshore, a technological arm of the Woods Hole institute, watched as a mooring winch lowered a 1,140kg anchor to the bottom of the sea. Floating on a tether a few metres above it was an acoustic listening device the size of a pineapple. It will monitor whale calls within the New York Bight, the wedge of continental shelf between the south shore of Long Island and the New Jersey coast. The array will be powered by a lithium battery within a bright orange buoy bobbing at the surface.
Researchers will identify whale species by their distinctive call patterns and will approximate their locations on continually updated digital maps. At 7.20pm on July 4, the first whales were detected. The calls of one or possibly two fin whales were identified, based on the species' signature low-frequency pulse, which was repeated in regular patterns every 15 seconds.
The researchers will also conduct visual reconnaissance from boats and by aircraft. They will tag some individual whales for long- term tracking. And a glider (a small submarine powered by wave energy and sunlight), will zigzag across thousands of square km of ocean listening for whale activity.
Critically, scientists will be tracking how close whales venture to New York's crowded shipping lanes, and they hope to send out alerts to mariners, through the Coast Guard and the Port Authority of New York and New Jersey, urging them to slow down when the animals are nearby.
Less is known about the impact of ship traffic on whales in New York than in the Boston area, where there has been a real-time underwater acoustic monitoring system in place since 2008.
The fortunes of the New York region were once intimately linked to whales. Small-scale whaling in Long Island dates to the 1640s; the blubber of the right whale was used for lamp oil and to make soap and margarine. Many species were brought to the brink of local extinction as the result of a whaling boom in the mid-19th century. As coastal whale populations crashed, whalers ventured farther - into the Arctic and to Hawaii - until the industry moved in the late 19th century to San Francisco.
Demand for whale oil plunged with the rise of kerosene. But the market for whale meat was strong even into the 1960s. Whale populations were decimated by industrial-scale slaughter fuelled by the use of exploding harpoons in the 20th century.
That all began to change after the International Whaling Commission banned hunting in 1986. Critically endangered species, like the North Atlantic right whale, began to see modest increases in population. Still, there are only about 500 right whales in the North Atlantic today, according to the National Oceanic and Atmospheric Administration.
All of New York's whale species are listed as endangered, and human activity continues to have a lot to do with that status. Dr Kimberly Durham, the rescue programme director of the Riverhead Foundation for Marine Research and Preservation on Long Island, said 2015 was the worst year yet for whale mortality: "Nine dead whales, mostly humpbacks, washed up on Long Island beaches, almost double the number in our previous peak year of 1991." Most of the carcasses had wounds consistent with ship strikes.
One unlucky humpback, Dr Durham said, was found entangled in gillnetting, which is often deployed to catch squid and herring.
Dr Mark Baumgartner, a marine ecologist at Woods Hole and a director of the New York whale project, hopes the data from the study will be used to "designate areas where we don't allow fishermen to set fixed gear". He expects that shipping channels may need to be moved to protect New York's whales, based on the success of the Boston whale surveys, which have led regulators there to change shipping lanes to avoid places where the animals routinely feed.
The National Marine Fisheries Service has mandated that ships slow to 10 knots in coastal areas frequented by whales to prevent collisions. Ms Barbara Yeninas, a spokesman for Evergreen Line, one of the largest container ship companies in the world, said the speed limit is "a small inconvenience we are happy to comply with to protect marine mammals". Mr Robert Kunkel, the president of Alternative Marine Technologies, a ship builder and designer based in Connecticut, said it is in the interest of the shipping industry to comply. "Hitting a whale is creating a problem for the shipowner, too. He has to see if he has propeller damage or hull damage."
Ship strikes are not the only threats to whales. Propellers and engines produce sounds in the same low-frequency range that whales use to communicate. Human-generated underwater noise doubled every 10 years during the last half of the 20th century, said a report by the United Nations Environment Programme. That cacophony is having a huge impact on life under the waves. Dr Baumgartner compared it to a cocktail party at which everyone is talking at once and you can't hear the person next to you.
Right whales in the Boston area stopped communicating with one another when ships were passing nearby, research by Professor Christopher Clark, who studies bioacoustics at Cornell University, shows. The noise makes it hard for the animals to hear each other. Dr Clark said: "Over a month on average, whales are losing approximately 85 per cent of their opportunities to communicate." That's devastating for creatures which vocalise to find mates, to forge friendships and to share information about food sources.
The New York project will monitor ship noise to assess if it is having negative effects on whale behaviour. But the biggest human impact on whales in the region is likely to come from climate change.
"Warming waters may already be responsible for a large increase in sightings of humpbacks in recent years near the entrance to New York Harbour," said Mr Paul Sieswerda, the founder of Gotham Whale, a non-profit that offers whale watching trips.
In 2012, he said, whale watchers spotted 25 whales; by 2014 the number had climbed to 107. Mr Sieswerda said warming oceans had brought vast schools of menhaden - a favourite fish of humpbacks, which eat more than a Volkswagen Beetle's weight of seafood every day - from their usual haunts off Chesapeake Bay north to the New York Bight.
Dr Baumgartner said the jury is still out on the future for whales in New York. "One of the real scientific imperatives is to get an observing system out there that can listen over years and hopefully decades, so that we can document the really important changes that climate change is bringing to our ocean - and to our whales," he said.
NEW YORK TIMES