In California, young limpets, up to ten millimetres in diameter, often live on the opercular plates of gooseneck barnacles, Pollicipes polymerus and on mussel shells.
In a carefully designed series of experiments they recorded the direct and indirect results on the numbers of goose barnacles, sea mussels, acorn barnacles, starfish and predatory whelks (Nucella spp.) present in the area.
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Predators on gooseneck barnacles include the glaucous-winged gull (Larus glaucescens), the black oystercatcher (Haematopus bachmani), the ochre sea star (Pisaster ochraceus) and the six-rayed star, Leptasterias hexactis.