The tuna was a type of edible fish native to Earth.
In an illusion created by the Talosians in 2254, Vina brought chicken tuna sandwiches along on their picnic that were made based on a recipe used by Christopher Pike's mother. (TOS: "The Cage")
In 2370, in effort to assist Data in training his cat Spot, Geordi La Forge told Data about a trick his sister, Ariana, used to train her cat. According to Geordi, his sister walked around for two months with a piece of tuna in her blouse. (TNG: "Force of Nature")