Michael Paige said he had gone for a swim in the waters on Tuesday and on his return to the beach, he hit the net as he was in shallower water just outside of the moorings.
His worry was that it was a risk to boats, swimmers and other water users.
‘I want to warn people about the net and be aware of it as it’s a popular area for swimming,’ he said.
‘Fortunately it just brushed down under me as it was flat calm, but if there had been any form of swell of wave action or anything I could have easily got tangled in it.
‘Entanglement is what they are there for, but for fish, I think people should be warned because it’s the last thing you want to hear that somebody has drowned being stuck in the net.’
The support floats and rope, he said, were about six inches under water at two hours after low water, though he could not see any marker buoys.
‘I know people net like that and I’m not criticising how people fish,’ added Mr Paige.
‘I’ve never seen it like this though where it’s a danger to people, it’s probably around 100m long, and I couldn’t see any markers to warn people it was there – for me it’s inappropriate.’
The rules currently state that between 1 October and 31 April, trot lines and set nets can be used within restricted waters provided they are set below the halfway mark of the tide, and are not exposed to the air for more than one hour per tide.
It advises all beach users to remember that during this period care must be taken if walking, riding or swimming below the half- tide mark.
Outside of restricted waters set nets and trot lines may be used without restriction or controls other than they must be
marked with the vessel name and number.
Castel constable and current harbour master for the parish, Nick Vining, said the person who laid the netting had done nothing wrong.
‘The person who was netting is a commercial fisherman with a GU licence,’ he said.
‘His licence states what he is permitted to catch, and the method he can use.
‘I saw him set the nets and at no time were they dry or of any concern to any boats or swimmers.’
He added that it was completely in line with the rules and had even spoken to senior Sea Fisheries officer David Wilkinson to clarify if the rules had changed. He confirmed to him that the rules were current and no laws were broken.
The fisherman who owns the netting has been contacted for comment.