まるさばでわありませんでした
丸鯖ではありませんでした
marusabadewārimasendeshita

Noun
Desu Copula

The polite, past negative form of まるさば

1. Was not a round mackerel.; Was not a horse mackerel.

Past/Perfective
Negative
Polite
Formal Register
Usually Written in Kana