The Marine Conservation Society (MCS) claims the species is running low because of over-fishing and has now suggested it only be eaten occasionally.
The removal by the MCS of mackerel from its list of “fish to eat” comes after the Council, which certifies fish stocks that are managed sustainably, suspended its certification of the north east Atlantic mackerel fishery.
But fishermen in Fleetwood say scientists and statisticians are being too cautious and they should investigate their findings further.
Leon O’Flaherty, chairman of Fleetwood Fishermen Reunion, said: “Mackerel has travelled around in shoals of thousands of tonnes for a long time and there’s still quite a lot out there.
“It’s certainly going to take money away from people in Fleetwood and affect their living.
“They’ve got a lot of quotas on fishermen but we’ve already proved the ocean is full of the stuff and scientists haven’t always got it right.”
The MCS now suggests mackerel should only be eaten occasionally, with herring and sardines a good alternative.
Fisherman Lionel Marr, chairman of the Jacinta Trust, is now in charge of restoring and looking after the heritage of the famed former trawler moored at Fleetwood Dock.
He said: “Firstly, there’s plenty of mackerel in the sea.
“We are not catching a lot of it in Fleetwood, but the fishermen at the scene know exactly what’s going on.
“Scientists look at data of stocks to make a decision, but when you talk to fishermen you find there’s more fish in the sea than people are making out.”
Mr Marr says he is hopeful a new law, which prevents fishermen from throwing fish back into the sea if they are over their quota, will soon be approved to help people trying to make a living from the industry.
He added: “If the fish are thrown back after they die, they go straight to the bottom of the sea bed and pollute the sea.
“But if this law is released, it will hopefully make fishermen better off.”
Bernadette Clarke, fisheries officer at the Marine Conservation Society (MCS), said movement of shoals had meant the species was now being over-fished.
She added: “The stock has moved into Icelandic and Faroese waters, probably following their prey of small fish, crustaceans and squid. As a result, both countries have begun to fish more mackerel than was previously agreed.”