iruka means "Dolphin" in English.

iruka is normally written with katakana, as イルカ.
iruka written with hiragana is いるか.
iruka written with kanji is 海豚.
These are jouyou kanji 常用漢字, taught in junior high, chuugakkou 中学校.
Romaji i ru ka
Meaning Sea Pig
School Level 小2,

Orthography Notes

  • iruka is a jukujikun 熟字訓 reading for 海豚 in this word. That is: those kanji are only read that way when they come together like that.

Further Reading

Wikipedia: 海豚 (Dolphin)