Log salmon regularly appearing in city (4)
I believe the answer is:
oslo
'city' is the definition.
(Oslo is an example)
'log salmon regularly appearing' is the wordplay.
'regularly appearing' means one should take alternating letters.
'log'+'salmon'='logsalmon'
The alternating letters of 'logsalmon' are 'OSLO'.
'in' is the link.
(Other definitions for oslo that I've seen before include "Northern capital of Czechoslovakia?" , "Nordic city" , "Go solo to European capital" , "Norwegian capital" , "Capital in throes of go-slow" .)