The most common and most likely answer to this crossword clue is the 5 letter word PIKES
P
I
K
E
S
Buddy explains!
The straight part
We know that "Marine creatures" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case marine creatures = pikes.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 PIKES mean?
PIKES noun- A very long spear used two-handed by infantry soldiers for thrusting (not throwing), both for attacks on enemy foot soldiers and as a countermeasure against cavalry assaults.
- A sharp point, such as that of the weapon.
- A large haycock.
- Any carnivorous freshwater fish of the genus Esox, especially the northern pike, Esox lucius.
- A position with the knees straight and a tight bend at the hips with the torso folded over the legs, usually part of a jack-knife.
- A pointy extrusion at the toe of a shoe.
- Especially in place names: a hill or mountain, particularly one with a sharp peak or summit.
- A pick, a pickaxe.
- A hayfork.
- A penis.
- Short for turnpike.
- A gypsy, itinerant tramp, or traveller from any ethnic background; a pikey.