50-year-old Thomas Edwin Cooke pleaded guilty to a charge under the Fisheries Act.
MPI spokesman Howard Reid says Cooke hid 20 paua in a sack in a culvert, intending to pick them up under the cover of darkness - but fisheries officers found them.
Reid says huge quantities of the Kaikoura shellfish died after the quakes - and there is no excuse for flouting the rules.