Fiona Collins, who also choreographs, is so flawlessly fluid in her movements that her hands, dancing along a strip of light and the mirror of the water’s surface, seem more marine creature than human appendage. In fact, Nawalowalo and her four-strong company evoke the sea, its mystic potency, its hidden treasures and the mixed blessing of its link to Western traders, with such impeccable, transparent, proud skill, you can almost taste the salt spray of their distant ocean. But then, with a bump, you’re back in the Barbican, worrying about whether they’ll all get ear infections.