The most common and most likely answer to this crossword clue is the 8 letter word LOBSTERS
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More clues leading to the result LOBSTERS
Buddy explains!

The straight part
We know that "seafood" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case seafood = lobsters.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 LOBSTERS mean?
LOBSTERS noun- A crustacean of the Nephropidae family, dark green or blue-black in colour turning bright red when cooked, with a hard shell and claws, which is used as a seafood.
- A crustacean of the Palinuridae family, pinkish red in colour, with a hard, spiny shell but no claws, which is used as a seafood.
- A soldier or officer of the imperial British Army (due to their red or scarlet uniform).
- An Australian twenty dollar note, due to its reddish-orange colour.
- To fish for lobsters.