Police say a "turf war" over cockle beds may be the cause of a fight which broke out in Askam in Cumbria.
One man needed hospital treatment after a fight amongst a "large group" of Chinese cockle pickers at 0730 BST on Thursday.
The beds at Askam were recently opened to harvesters after being approved by the Foods Standards Agency.
Cumbria Police are trying to trace three vehicles seen carrying Chinese nationals from the scene.
Residents and businesses in Askam feared the area would be swamped by hundreds of cockle pickers when approval was given to commercially harvest the animals in the Duddon Estuary.
The cockle beds are known to be of high quality and have not been commercially harvested for decades.
Taken to hospital
It was expected that the millions of pounds in potential profits would attract hundreds of cocklers a day to the area, which is close to the Roanhead nature reserve.
A Cumbria Police spokesman said: "A member of the public alerted us to a large fight which was taking place at Askam.
"When officers arrived, they found a Chinese national who had received injuries and was taken to Furness General Hospital."
The nature of the man's injuries have not been released.
But the police spokesman said one line of inquiry was the likelihood of a row over the cockle beds.
Police said they were trying to trace three cars carrying Chinese nationals that were seen driving together.
They were a Renault Megane, and Vauxhall Cavalier and another saloon car.
Immigration officials, council bosses, fishery agencies and the police are monitoring the situation.
Barrow Borough Council has called for a voluntary code of practice among cocklers to limit damage.