ヨーロッパいがいであれば
ヨーロッパ貽貝であれば
yōroppa igaideareba

Noun
Da Copula

The "-eba" conditional form ("if/when…") of ヨーロッパいがい

1. If/When European oyster ; If it were a European oyster

Ba Conditional
Usually Written in Kana