Periods of fishy noises outside ship (8)
I believe the answer is:
sessions
'periods' is the definition.
(session is a kind of period)
'fishy noises outside ship' is the wordplay.
'fishy' indicates an anagram.
'outside' indicates putting letters inside.
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'noises' anagrammed gives 'seions'.
'seions' going around 'ss' is 'SESSIONS'.
'of' is the link.
(Other definitions for sessions that I've seen before include "Sittings, terms" , "US composer" , "Periods of sustained drinking" , "Meeting periods" , "Periods devoted to a particular activity" .)