The officers were in a RIB beside the fishing vessel Master B, skippered by David Andrew Sullivan, about a mile off Bouley Bay at the time of the incident on 30 January.
The court heard that lobster fisherman Sullivan (23), of Rue du Pont Marquet, St Brelade, shouted ‘F**k off or I will knife your f***ing RIB’.
He then warned: ‘If you take my pots I will come up to Howard Davis Farm and knock you out.’
One of the officers was concerned for his safety and the RIB left the area.
Sullivan admitted a charge of intentionally obstructing a fisheries officer in the course of his duties.
He also pleaded guilty to using ‘parlour’ lobster pots that had no escape hatches to allow smaller creatures to escape. The court heard that Sullivan had a string of ten pots in the water, only one of which had an escape gap – and that was too small.
The defendant also admitted leaving fishing gear in the sea that did not have identifying markings of the boat’s registration number.
The Magistrate, Bridget Shaw, said that Sullivan had been in trouble for sea fisheries matters in 2015 and 2016. However, she said that an individual could only be fined for these offences.
‘The way you behaved towards the fisheries officers was not what would be expected of someone who understands that regulation is necessary to protect species and stocks,’ she said
She ordered that a social inquiry report be prepared prior to a sentencing hearing on 30 May.