Fish holding short stick in biannual event (8)
I believe the answer is:
solstice
'biannual event' is the definition.
(the winter and summer solstices)
'fish holding short stick' is the wordplay.
'fish' becomes 'sole' (sole is a kind of fish).
'holding' is an insertion indicator.
'short' means to remove the last letter.
'stick' with its final letter removed is 'stic'.
'sole' going around 'stic' is 'SOLSTICE'.
'in' is the link.
(Other definitions for solstice that I've seen before include "Midsummer or midwinter point" , "it occurs biannually" , "When night and day are most unequal" , "Shortest or longest day of the year" , "Time of highest or lowest noon sun" .)