Can be a nuisance when a ship is wrecked (5)
I believe the answer is:
aphis
'can be a nuisance' is the definition.
I can't judge whether this defines the answer.
'a ship is wrecked' is the wordplay.
'is wrecked' is an anagram indicator.
'ship' is an anagram of 'phis'.
'a'+'phis'='APHIS'
'when' acts as a link.
Can you help me to learn more?
(Other definitions for aphis that I've seen before include "Sap-sucking garden pest" , "Small insect" , "sucker?" , "Plant louse" , "Greenfly" .)