Definition of "Tuna"

Tuna was carried down by the flood; and when Maui saw him in the net he stretched forth his arm and with a blow of his stone axe smote Tuna and cut off his head, and it and the tail fell into the ocean. [...] The head became fish, and the tail became the koiro (ngoiro—conger-eel).

1887, John White, The Ancient History of the Maori, page 84