How many syllables in tuna?

Definition of tuna:

tuna (noun):

important warm-water fatty fish of the genus Thunnus of the family Scombridae; usually served as steaks.

any of various large vigorous scombroid fishes (as of the genera euthynnus, katsuwonus, and especially thunnus) that are usually dark above and silvery below and include many that are valued as food or sport fishes see albacore, bigeye tuna, bluefin tuna, dogtooth tuna, little tunny, skipjack tuna, yellowfin tuna