Scientists, environmentalists and fishermen have banded together to criticise plans to dredge a Cornish harbour.
Moves are afoot under the Port of Falmouth Development Initiative to dredge the town's harbour to deepen it to allow super-liners to dock.
Hundreds of jobs are promised under the scheme with extra tourism pounds for the local economy.
However, plans have stirred up a hornets' nest amongst environmentalists because the maerl beds will be ruined.
The beds are deemed by some to be vital to the area's marine eco-system in providing habitats for plant and sea-life.
Friends of the Earth in Falmouth recently hosted a debate at the 'Poly' in the town where fears over dredging were voiced.
Dr Jean-Luc Solandt of the Marine Conservation Society said the Falmouth and Helford Special Area of Conservation was seen as a "unique and valuable marine habitat, meriting strict protection under UK and EU law".
Dr Solandt said maerl beds hosted a vast array of plant and animal species and formed a key breeding ground for fish and scallops.
He said maerl was also very slow-growing, with some beds estimated at up to 8,000 years old, and is highly vulnerable to impacts from the dredge both within and beyond the immediate dredging path.
Dr Solandt said: "The law as it applies to the Special Area of Conservation is clear.
"There has to be proof that there will be no deterioration in the condition of the maerl.
"The Marine Conservation Society cannot believe that this will be the case given the huge quantities of silt that will be released into the water column and spread around the site from this proposal."
And Dave Thomas, a local fisherman who co-founded the Falmouth Bay and Harbour Action Group to oppose the dredging operation, said more than a million tonnes of spoil from the dredge would "simply be dumped offshore" in Falmouth Bay.
Mr Thomas said the spot was where a smaller dump in 2001 of 47,000 tonnes wiped out the mackerel and whiting fishery for several years.
He said: "The fishing didn't really recover until 2009.
"So you can just imagine what 1.1 million tonnes of this stuff is going to do."
Mr Thomas said massive amounts of silt, some of it contaminated with toxic substances such as TBT from anti-fouling paint, would inevitably spread over a very wide area of the seabed.
He said: "Both aspects of the proposals, the dredging and the dumping, threaten the livelihoods of the entire inshore fishing fleet of Falmouth and Helford – oystermen, potters, netters and handline fishermen, all fishing in the most sustainable manner possible."
Tom Scott of Falmouth Friends of the Earth said the case against dredging had not yet been properly heard.
He said: "We need to be looking at developing the local economy and creating jobs in ways that do not damage the natural environment."
In September the University of Plymouth began carrying out a six-month independent dredging trial.
Its findings are expected to be reported to the Marine Management Organisation (MMO) in the Spring before the body makes a final decision on the scheme.
Falmouth Harbour Commissioners are one of the major players in the Port of Falmouth Development Initiative. A spokesman said the overall percentage area of dead maerl proposed to be dredged is less than 2% of the known area of dead maerl habitat that exists within the Fal and Helford Special Area of Conservation limits.
He said: "The issue of sediment movement has been extensively modelled and is something the MMO will examine closely as part of its independent and detailed deliberations into whether or not to grant consent to dredge.
"The Port of Falmouth Development Initiative partners are considering potential uses for spoil to reduce the amount that would be deposited offshore from any dredge, and we have offered to meet representatives of the fishing industry to explain this."