Dyfed-Powys Police are investigating a complaint that a fisherman in Cardigan has suffered more than £1,000 worth of damage to his lobster pots.
Lobster pots can cost up to £70 each
But police say they are also looking into a spate of lobster pot thefts in local waters over the last two weeks.
Pots have also been damaged in both Cardigan and nearby Crymych and they have received allegations that fishermen could be responsible.
A police spokeswoman confirmed that they were investigating a complaint that lobsters were taken from pots and then some of the pots are being damaged.
She said: "More than £1,000 worth of damage has been caused to a fisherman's property. He claims that other fishermen are responsible."
A police spokeswoman in Cardigan added: "One fisherman has said that 40 of his lobster pots have been damaged over a period of time.
"Not only is the fisherman losing out on the value of the lobster, but he is having to pay for new pots which can cost up to £70 each."
It's alleged that lobsters are being stolen
Chairman of Cardigan Bay Fishermens' Association, Winston Evans, said: "When I started fishing 40 years ago there was just one lobster fisherman in Cardigan now there are many more boats and some with a crew of two.
"The aims of the association were to cap the number of fishermen and fish less, but that's gone in the opposite direction.
"This problem only exists in Cardigan at the moment and that's because there are too many fishermen trying to fish too small an area.
"If lobster pots are being damaged deliberately then that's very bad."
Lobster fishing off the mid Wales coast at one time was big business.
FACTS ABOUT LOBSTERS
Lobsters taste with their feet
They have three stomachs
They can live to be 100-years-old
European Lobsters take five years to reach a saleable size of just over a pound
It was common for pots to contain 10 lobsters, but since the influx of extra boats the ratio has reduced to about one lobster every three pots, Mr Evans said.
On average, fishermen receive £5 per lobster while they cost roughly £12 each at restaurants.
A Cardigan fisherman, who refused to be named, said there was "quite a bit of European Objective 1 money floating about" to refurbish boats.
That was one of the reasons why the number of boats fishing out of Cardigan had doubled to 10 in a year, he added.
Anyone with information is asked to call Cardigan police on (01239) 612209.