Tiny Fish Lures Huge Humpbacks
One Reason Whales Return To Sound
One of the smallest, oddest and least-studied fishes in Long Island Sound may be playing a role in attracting one of the world’s largest ocean creatures to the waters along Connecticut’s coastline.
The tiny fish is called a northern sand lance or sand eel, and experts say it could be one of the reasons why massive humpback whales have returned to the Sound in recent years.
Sand lances, at 3 to 6 inches in length, are true fish but look like little silvery eels. They are also a favorite food of humpbacks, which can reach up to 60 feet in length and weigh as much as 40 tons.
“Most people don’t even know their name,” David Wiley, the re-
search coordinator for the Stellwagen Bank National Marine Sanctuary off Cape Cod, said of sand lances. “But they’re extremely important.”
After many decades of absence, humpbacks returned to the Sound beginning in 2015 and at least a few have been recorded feeding in the waters between Connecticut and Long Island or off New London every year since.
Marine scientists believe the sand lance is far from the only reason why humpbacks have been returning to the Sound. They point out that other prey species favored by humpbacks, including menhaden and herring, have also been on the increase in the waters off Connecticut’s shoreline and are likely key to the humpbacks’ return.
“It’s a good sign for Long Island Sound,” said Peter Auster, senior research scientist at Mystic Aquarium and a professor emeritus of marine sciences at UConn. It’s also an indication of how much the Sound’s waters have improved, he said.
But humpbacks, other types of whales, seabirds like terns and puffins, sharks, seals and prized commercial and recreational fish such as striped bass and bluefish find the sand lance a key forage fish.
During the day, sand lances form schools of thousands and tens of thousands to feed on plankton near the ocean’s surface, making it simple for humpbacks to scoop them up in their huge mouths.
At night, these peculiar fish take the unusual course of burying themselves in rough sand in shallow waters to try and escape predators.
Experts readily acknowledge that they don’t know enough about the fish. They agree that sand lances are present in the Sound’s waters, but have no solid information as to their numbers.
“Sand lances are one of the [marine] species that has really been understudied,” said Chris Murray, who is helping to research sand lance reproduction at the University of Connecticut as part of his work to get his doctorate.
Murray’s project is looking to find out why sand lance populations on the Stellwagen Bank have been rising and falling dramatically year to year, and if climate change is playing a role.
Jon Brink, senior naturalist and a captain with Hyannis Whale Watch Cruises on Cape Cod, said that when sand lance populations drop along the Stellwagen Bank, “A lot of the whales we expect to be here aren’t here.”
Brink said he believes those missing humpbacks may be shifting their hunting grounds to the south, including to Long Island Sound, in search of sand lances and other forage fish.
“The challenge here is that I don’t know of anyone who is studying them [in Long Island Sound],” said David Hudson, a research scientist at the Maritime Aquarium at Norwalk.
A big part of the problem with trying to study sand lances is that they’re very difficult to catch with ordinary fishing nets and routine survey trawls, Hudson said. Sand lances are so skinny and small that they just slip right through normal nets.
“If you’re going to do a population survey, you have to be able to catch them,” Hudson said.
Wiley said sand lances are caught in massive quantities in the North Sea, off the northern coast of Europe, for use in fish meal and other products, but have little economic impact in this country. “Because they’re not a commercial fish [in the U.S.], people really haven’t studied them,” Wiley said.
Auster agreed, saying that lack of commercial interest means there isn’t much industry or government funding for what can be costly research studies.
“So we can’t keep our thumb on the pulse of the sand lance population,” Auster said. But Auster added that there are numerous shallowwater habitats with rough sand bottoms along the Connecticut coastline of the sort preferred by sand lances.
Connecticut fishing blogs have for years referred to “dense schools” of sand lances drawing large numbers of striped bass, bluefish and other predators in close along shallow sandy areas to feed.
A state marine fisheries report in May noted that “sand eels [sand lances] have made their way to our shores, especially in Stratford, Milford, West Haven and New Haven.”
David Molnar, the DEEP marine biologist who authored the report said the number of sand lances is slowly decreasing in Long Island Sound as the water gets warmer.
“They are mostly a cold-water species. … This is really the southern part of their range,” Molnar said.
Other cold-water species, including lobsters, are in decline in the Sound as climate change continues to raise average water temperatures off Connecticut’s coast, according to marine scientists.
Molnar said this little fish is a major target for all kinds of marine predators, including whales, but says the humpbacks are likely drawn to the Sound by the increasing numbers of other types of forage fishes.
“There are so many more menhaden than sand eels,” Molnar said, agreeing with other Connecticut experts who believe the humpbacks are primarily hunting the big schools of menhaden.
On the other hand, Molnar says the Sound is due for a large increase in its sand lance population, which appears to boom in a cyclical fashion every few years.
The Mid-Atlantic States Marine Fisheries Commission has recognized the importance of sand lances and other forage fish as food for many commercially important fish species by setting strict limits on their harvesting, Wiley said. The concern is that commercial fishing of forage fish like the sand lance could lead to population declines in economically important species that need them for food.
But Wiley said there are currently no restrictions on commercial harvesting of sand lances in the New England region.