Other Location?

is there a reason the doki doki island event is listed? it's used in the event but i'm not sure why it's listed here, i can't find it in any of the shops

edit: just realized bluefin tuna is only available on the island. is that the only reason it's listed?

Onion Fried Tuna is one of the 5 or so Doki Event Dishes. It can only be crafted during the event, but yes it's technically not 'rewarded' by the event in a normal fashion. In fact, it's a quest during the event to make it. Tuna is even more confusing in my opinion, because despite Rano Tuna existing 'Tuna' is also an event exclusive fish used in event exclusive foods.