I saw a seal show at the aquarium.
The seal was resting on the ice.
アザラシ is an earless seal, while トド (Steller sea lion) is a large eared seal in the アシカ family, not a true seal.
counter for small animals · counter for rolls of cloth · archaic counter for horses · roll of cloth
Katakana spelling is standard; the word is usually written in kana.
Hiragana spelling, also common.
Rarely used kanji form; the reading あざらし is a jukujikun. The on'yomi かいひょう is also possible but very rare.
The word アザラシ is of uncertain origin. It may be related to 痣 (aza, 'bruise') and ラシ (rashi, possibly from 海獺 rashio, 'sea otter'), but this is speculative. The kanji 海豹 literally mean 'sea leopard' and are a jukujikun reading.