Translation

ottā means "Otter" in English.
It's a katakanization, a loan-word.

ottā is normally written with katakana, as オッター.
ottā written with hiragana is おったー.
ottā does not have kanji.
Romaji o ttaa
Katakana
Hiragana

Orthography Notes

Synonyms

kawa-uso カワウソ, uso , oso , datsu , Lutrinae.

Further Reading

Wikipedia: (Otter)
rakko 海獺.