noun
river dolphin
Refers to freshwater dolphins found in rivers, such as the Amazon river dolphin or the Ganges river dolphin.
アマゾン川にはカワイルカが生息している。
River dolphins inhabit the Amazon River.
イルカ is the general term for dolphin, while カワイルカ specifically refers to freshwater river dolphins.
Compound of 川 (kawa, 'river') and 海豚 (iruka, 'dolphin'). The kanji spellings are straightforward combinations of the characters for 'river' and 'dolphin'.