Anglers are outraged that a commercial netting company has been granted the rights to a crucial stretch of water near the mouth of an important salmon river.

The Scottish Wild Salmon Company, a brand name for Usan Salmon Fisheries Ltd based near Montrose in Angus, announced it had acquired angling and salmon netting rights in the Ythan estuary and adjacent foreshore on Aberdeenshire coast.

It has reignited a long running war of words between anglers and salmon netters particularly on the east coast.

The Aberdeen and District Angling Association (ADAA), which describes itself as Scotland's largest community-based angling organisation with 1100 members, has expressed its "anger and despair" at the news, particularly since the rights in question have not been exercised since 1997.

The company says that one of its first actions will be to use non-lethal methods to divert the estimated 500 seals around the estuary, which should benefit salmon numbers for everyone on the river. It would also encourage public angling where it has the rights.

However, Bob Dey, president of ADAA, said: "We are totally dismayed these nets are due to start operating again. Our association has extensive fishing rights on the River Ythan - it is a working man's river, available to all our members in Aberdeen and Aberdeenshire."

He said that over many years the association's members had contributed large sums towards fish conservation on the river, including the buyout and closing of the netting station just north of the mouth of the Ythan.

"It is galling that all our efforts are jeopardised by the arrival of a major salmon netting company, which has never paid a penny towards conservation on the Ythan and has a history of catching as many fish as possible for commercial gain," he added.

Mr Dey said the real argument was not with the new commercial netting operator, however: "It is with the Scottish Government which has woefully failed to introduce legislation to cease the practice of coastal netting for Atlantic salmon and sea trout."

Salmon caught by rods cannot be legally sold, unlike those netted, and Mr Dey said Scottish ministers had to decide whether supplying wild salmon to elite restaurants in London, Paris and Moscow was more important than ensuring the future of an iconic species in rivers such as the Ythan.

George Pullar, director of the Scottish Wild Salmon Company, said it was spending a lot of money using acoustic seal deterrents, which send out noises at frequencies which can not be heard by humans, but which the seals will try to avoid.

He said all anglers would be welcome and would not have to be a member of a club. Some limited netting would be required on the foreshore and lower estuary.

The Pullar family already operates several netting stations along the Angus coast from Montrose to Arbroath as well as Murkle/Castlehill on the north coast of Caithness and Gardenstown in the Moray Firth.

In 2012 netting operations caught 41.7% of the annual Scotland retained or landed salmon catch but only 15.9% of the total catch, which included those fish landed and released by anglers.

A Scottish Government spokesman said: "Scottish ministers would, of course, be concerned to learn of any activity that would threaten the sustainability of salmon and sea trout stocks and the wider ecosystem of the Ythan.

"We encourage the Ythan Fishery Board, in line with their statutory responsibilities, to monitor the impact of any new fisheries on stocks and to explore conservation measures as an option if evidence suggests these are necessary.

"Ministers have asked the chair of the independent review of wild fisheries to consider the management of salmon netting."