Whitebaiters try their luck at netting the delicacy in the Kakanui River mouth which was surrounded by sea fog yesterday.
MetService meteorologist April Clark said sea fog was a common occurrence, caused by a high pressure system sitting to the east of New Zealand.
''Winds from the north bring inwarm moist air, and when you've got cool sea surface temperatures, it cools that little bit of air above the sea.
''The moisture in it condenses and that's what creates sea fog.''
Ms Clark said the high pressure system would possibly cause the fog to appear in the harbour again this morning, but would not reappear tomorrow because the high pressure system was moving off to the east.
