Looks like delicious sushi, doesn't it?
But actually they are sweets made for April Fools by Miyakin, a local okashiya, i.e. a bakery/sweets store. (It's actually originally from Shichinohe, but there's a big shop/cafe in Towada, next to the Tsutaya.)
The seaweed is really seaweed, but everything else is a confectionery. (The soy sauce is kuromitsu, a kind of molasses.)
Other than the sushi, Miyakin also made shina soba (支那そば a.k.a. ramen) and a Miyakin burger.
Even though April Fools is over, you can still buy the April Fool sweets up to this Sunday, April 7.
宮金寿司 Miyakin Sushi 850yen (5 pc sushi, "ginger" & "soy sauce")
宮金麺屋 支那そば Miyakin Menya Shina Soba 300yen
ミヤキンバーガー Miyakin Burger 250yen
Miyakin April Fools Sweets flyer: