Two baby white sharks have been caught off Long Island and given a big task — help researchers find out where the young predators hang out, officials said Saturday.

A 50-pound, 4-foot female was the first baby white to be tagged in the North Atlantic by Ocearch, the nonprofit that goes around the world studying sharks and is on a two-week expedition to learn if the Island’s waters are home to juvenile ones.

“This is a real step forward for the ocean right here, probably the most historic fish we’ve ever caught,” Ocearch founder Chris Fischer said on the research vessel in a video posted live on the group’s Facebook page as the shark was tagged at sunset Friday.

Then about 12 hours later and 25 miles or so off Montauk, a 67-pound, 5-foot male was spotted, said Jon Forrest Dohlin, director of the Brooklyn-based New York Aquarium, one of several partners in the expedition.

“It’s so cool,” Dohlin said.

The exuberance busted out this weekend because the baby whites ended a sort of dry spell in shark spotting for the expedition. Small scouting boats had brought only three sharks the first week to the big research vessel, two dusky and one dogfish.

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As a sign of how little is known about young sharks, Dohlin said, scientists believe the two tagged ones were born this year but they don’t have better estimates of ages, only that newborn sharks are about three to four feet long.

Sharks eat the sick ones and help keep the ecosystem in balance, but their breeding habits, early years and travels are still a mystery. Boaters and fishermen have long seen sharks in local waters, but how the big fish coexist in New York City’s shipping lanes and with human activity are not clear.

Fischer named the female shark Montauk in honor of mariners’ history, calling the East End fishing hot spot a “special, special” place whose people had made him feel welcome.

The male was named Hudson, after New York’s famed river. A video of his tagging was also posted by Ocearch.

Montauk arrived at sunset a week after the ship had set out, a weight off researchers whose goal was to nab at least one juvenile white shark. As a shark scouting boat led it to the research vessel, equipped with a lift, the baby white did not fight.

Brett McBride, co-captain of the Ocearch vessel, was on the scouting boat and had been expecting another type of species when the fish swam by.

“When that thing went under the boat, I was like I think we got a baby white on us,” he said on the video.

A 47-minute video of the adventure showed eight or more people at times swarmed around the little predator, taking a tissue sample, measurements and attaching a tag to her fin. A blanket was put over her head. A hose put inside her mouth kept her gills wet, and when all the data-gathering was over, she took her time letting go of the hose.

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“That was crazy, right?” Fischer said afterward as clapping erupted to wish Montauk well.

The great whites are not threatened with extinction but the species’ survival hangs on the fishing industry, pollution and policies aimed at stopping the shark fin trade.

Montauk has been added to the group’s Global Shark Tracker, which allows people to see the pinged locations of each shark.

“Together we wait for the first ping,” Fischer had said. “We got to learn where the baby sharks go so we can make more big sharks and lots of fish for our grandchildren. Today was a big leap forward for that in the North Atlantic Ocean.”