おうにしようくろまぐろであれば
大西洋黒鮪であれば
ōni shiyō kuromagurodeareba

Noun
Da Copula

The "-eba" conditional form ("if/when…") of たいせいようくろまぐろ

1. If it were Atlantic bluefin tuna; If it is Atlantic bluefin tuna

Ba Conditional
Usually Written in Kana