A harbourmaster has raised safety concerns about people cockling on the Dee Estuary in north Wales.
Cocklers came from as far away as Scotland
Captain Charles Allister claims a number of fishermen cockling on Wednesday had overloaded their boats with shellfish to the point where some were barely floating.
"I'm worried about the lives of these people sitting in the boats," he said.
Around 400 people converged again on the estuary on Thursday after the temporary lifting of a cockling ban.
Capt Allister, the estuary harbourmaster, said: "The boats are barely afloat and some of the people don't even have a life jacket.
"There's been a very big operation carried out on the shore but despite that huge effort people are coming out from other places.
"You can't physically manage that many people on the estuary," he added.
He added: "I stopped six people today - they didn't have one life jacket between them."
Capt Allister has alerted Environment Agency Wales to his concerns and said a series of meetings would be carried out after cockling ends on Thursday and before it possibly resumes for a further two days later this month.
Extra officers have been drafted in by the Environment Agency, which received 700 licence applications.
Harvesting was suspended at the Salisbury Bank in 2003 because of a decline in the shellfish numbers.
Cocklers from Flintshire have been joined by people from as far afield as Scotland and Poland for the two-day resumption.
Only those with permits are allowed to harvest during daylight hours.