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Sports Center

Aug 14, 2017 12:10 PMPublication: The East Hampton Press & The Southampton Press

Sandbar Sharks, The Mysterious Feeder

Last summer, Nicholas Stark came upon this 100-pound sandbar, or brown, shark, which gobbled up bait meant for stripers in the Wainscott surf.
Aug 15, 2017 9:14 AM

East End ocean beachgoers have been treated to some spectacular marine wildlife sightings this summer, all revolving around—and feeding on—ubiquitous schools of full grown bunker, also known as menhaden. A type of herring, bunker travel in schools so dense and tightly packed that they are often visible from shore as dark patches on the surface of the ocean.As reported previously, every day this month I’ve seen whales and dolphins feeding on the bunker. The humpback whales put on the most dramatic show among the marine mammals, encircling the schools to compress them as tight as possible before lunging straight up from below with mouth agape to catch and swallow as many of the 9-to-10-inch-long bunker as possible. Their momentum often carries them well above the water’s surface, exposing their entire head and sometimes their huge, oversized pectoral fins as well.

But something else seemed to be feeding on the bunker from below, a piscivore that did not reveal itself with a “blow” or a fin, or even a splash. Every so often the school of bunker would erupt in a frenzy of movement that churned up the surface of the ocean, at times in a line that some onlookers thought might be a wave breaking on a hidden outer bar.

Bluefish? Stripers? Last Friday, Zack Dayton and Nick Miller, along with another friend, set out on paddle boards with fishing gear and an underwater camera in hopes of finding out. They each soon had a large, heavy fish on the line, and the water visibility was so good that they caught sight of their prey: sharks.

Two managed to work their way back toward shore and shallow enough water to ditch their boards and start reeling the sharks in. Both were eventually lost in the surf, but not before a few photos were taken.

I had no idea what species we were looking at. There was some speculation, based on the upper fin of the tail being much longer than the lower fin, that they had a thresher shark. But I later learned that the upper fin of the thresher’s tail is as long as its body from nose to the beginning of its tail, a dramatic-looking tail that is unmistakable.

I managed to reach Southampton High School science teacher Greg Metzger by phone for help in the ID. Greg was on his boat off Gurneys assisting the OCEARCH research vessel in their quest to capture and tag young-of-the-year white sharks with satellite transmitters. OCEARCH had tagged six young-of-the-year in August 2016, and thus far this August they’ve captured and tagged two.

Greg relayed that the shark photos were of a sandbar shark, otherwise referred to on the East End as brown sharks, one of several species including mako, dusky, and hammerhead that lurked beneath the bunker schools to feed.

The sandbar shark (Carcharhinus plumbeus) grows to 8 feet in the northwestern Atlantic and has a worldwide distribution, occurring on both sides of the Atlantic in warm-temperate coastal waters, the southern Indian Ocean, Hawaii, and the western Pacific. It is the most common gray shark found along the coasts of the Middle Atlantic states. It migrates in schools to wintering grounds from North Carolina south to Central America. Chesapeake Bay is the main nursery ground in the Atlantic region.

Mating occurs in June and, after an 11-to-12 month gestation period, the pups are born the following year in late May-early June.

They are a very slow growing species; juveniles grow an average of 4 inches per year, adolescents grow 2 inches per year, and adults grow less than an inch per year. They reach maturity at 12-15 years and live 20-25 years.

According to the most recent edition of “Fishes of the Gulf of Maine,” published in 2002, sandbar shark meat is highly marketable.

Fishing pressure on this species eliminated most large individuals from the eastern seaboard population, and it was uncommon to catch one greater than 6 feet in length. Before this species was managed in 1993, Northwest Atlantic sandbar shark stocks were reduced by 85 to 90 percent over a 10-year period. The current U.S. Fisheries Management Plan prohibits recreational and commercial harvest of this species, although “bycatch” still impacts its population.

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