A dominant shark lurks in the deep, dark ocean. Meet the sixgill.

On a balmy Caribbean evening in August, crew members aboard the the 184-foot exploration vessel the Alucia tied dead fish to the front of a small yellow submarine. 

They tightly wound the fish to a metal pole extending out from the undersea craft to tempt whatever might be lurking, three thousand feet below.

But Dean Grubbs, one of the researchers preparing the bait, didn’t intend to catch anything. Grubbs, a shark scientist at Florida State University, only hoped to attract a little-seen creature that largely dwells in the lightless ocean depths: the sixgill shark.

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