Absalom's Wake-Part Three-The Whale Rider — Nancy A. Collins

Young Jonah Padgett signed onto the whaler Absalom with romantic notions
of traveling to far-flung exotic lands and meeting strange and wondrous
natives. And they don't get much stranger than the ship's new harpooner,
Koro, who claims that their fates are bound by the mystery of the
dolphin amulet Padgett wears about his neck.