Translation

The Japanese word for "White Whale" is shiro-iruka 白海豚.

Romaji shi ro i ru ka
Hiragana
Katakana
Kanji 海豚
Meaning White Dolphin
School Level 小1 小2,

Synonyms

Beluga Whale, Beluga, Melonhead, Sea Canary.

Further Reading

Wikipedia: Beluga_whale