seawolf

noun

1. A strong-jawed North Atlantic fish of wolffish family Anarhichadidae, Anarhichas lupus.
2. (archaic)An elephant seal.
3. Any of various dangerous people and animals that attack at sea.

   “The seawolf twisted onto itself, its jaws clopping together near its own tail.”

   “Benjamin stood, gasping for breath and looking down at the dead corsair. "You were a worthy foe, seawolf," he murmured regretfully.”

   “Kebisu was regarded as a ferocious and cunning seawolf, who had raised his diminutive island to the state of marine fortress without so much as erecting a brush stockade; he had no fixed defences.”