The most common and most likely answer to this crossword clue is the 7 letter word LOBSTER
I've seen this crossword clue in The Guardian
L
O
B
S
T
E
R
More clues leading to the result LOBSTER
- Throws aquatic bird endless shellfish
- Seafood bishop fed to confused monarch
- Seafood to throw up on back of boat, briefly
- Throw up a lot of grim seafood
- Bloater’s not a bad sea food item
- Aims high most of time, providing seafood
- Seafood best cooked in liquid, or roasted to begin with
- Tosses half of butter for main dish
- Throw nearly all back that’s caught in the sea
- Throw back tailless crustacean
Buddy explains!

The straight part
We know that "sea food item" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sea food item = lobster.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 LOBSTER mean?
LOBSTER 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.
- Red-colored, especially from a sunburn.