The release of a draft list of potential marine Special Protection Areas is a major concern to the residents of South Uist, who are concerned by the impact on opportunities for fishing, cockling, seaweed collection and offshore wind, wave and tidal energy projects.
South Uist had a population of more than 7000 before the early 19th century. In the 2001 census the population stood at 1818 and in 2011 it was down to 1754.
The islanders claim the imposition of a marine SPA to the west of their island would make things worse by adding to the extensive range of designations and protections "already covering every square inch of South Uist."
They are also smarting that their firmly held objections to the inclusion of some areas of the island on a map of wild land area produced by Scottish Natural Heritage to help planners, were ignored.
They had argued that the so-called "Wild Land" of South Uist had been occupied, managed, altered, built on and farmed by island residents for thousands of years.
Now they believe they have a new fight on their hands, said Huw Francis, chief executive of community landlord Storas Uibhist.
He said: "The potential marine SPA follows close on the approval of the South Uist Wild Land Map, which despite strenuous local objections was even extended after the initial consultation to include an offshore island with a radio mast on it."
He said the continuing approval of environmental designations and protective measures imposed by SNH and Scottish Government, which in practice were often much more restrictive than stated at the consultation stage, "will further increase depopulation as local residents are constrained in how they can develop the local economy."
He continued: "It is ironic that in the rush to protect wildlife and restrict the activities of local residents it seems to be forgotten that these ecologically important areas are in such pristine condition only as a result of the sustainable management practices of local fishermen and crofters."
But an SNH spokesman said a marine SPA might not preclude fishing.
He said ministers were considering 14 new SPAs for marine birds, which may be needed to meet the requirements of the EU Wild Birds Directive, and one of them lies on the west coast of the Outer Hebrides.
But he said: "Given that these sites are already important and of sufficient quality to support the birds, it may be reasonable to assume that current fishing in many of these areas is largely compatible with the birds' interest.
"The aim is always to find ways to enable fishing whilst continuing to protect the birds. The same would apply to other forms of development and commercial activity in, or affecting, SPAs, including aquaculture and renewable energy development and shellfish harvesting."
He also said there could be a positive spin-off for tourism, as there were many nationally and internationally important habitats and species. "These have attracted recognition in the form of environmental designations to secure the future of these important features," he said. "Many of the features of these sites help to underpin the islands' tourism economy and some have proved useful in attracting external funding and jobs for environmental management projects."
Storas Uibhist became community landlord of South Uist Estate, encompassing most of the islands of Benbecula, Eriskay and South Uist, in 2006.