The most common and most likely answer to this crossword clue is the 7 letter word MANATEE
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More clues leading to the result MANATEE
- Fellow consumed eastern sea creature
- Sea creature fed last of people on island
- Aquatic mammal with 9, everyone said?
- Bloke took drugs, finding sea cow!
- China importing a new European mammal
- Fellow with some support for swimmer
- Old woman with a teen disturbed aquatic creature
- Chap dined on Eastern sea creature
- Marine creature mum has eaten — horrible!
- Consumed energy supporting fellow creature
Buddy explains!

The straight part
We know that "swimmer" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case swimmer = manatee.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does MANATEE mean?
MANATEE noun- Any of several plant-eating marine mammals, of family Trichechidae, found in tropical regions.