Europe's whitefish industry could collapse unless soon-to-be-implemented rules on the discarding of unwanted fish are abandoned or changed, the Scottish Fishermen's Federation has warned.

The alert was made in the run-up to the annual quota-setting summit of European Union (EU) fishing ministers in Brussels next month, which Scottish Fisheries Minister Richard Lochhead is scheduled to attend.

New EU rules to be introduced from January aim to slash discards - the practice of throwing surplus dead fish overboard. The rules, to be phased in between 2015 and 2019, are part of the new Common Fisheries Policy which got under way in January this year and will force skippers to land ­everything they catch.

It will begin by targeting pelagic (open ocean) fish, such as herring and mackerel, next year, then from January 2016 the ban will be extended to Scotland's mixed whitefish ­demersal (those that live near the seabed) fish, where the exclusive targeting of specific species with no "bycatch" of unintended fish is practically impossible.

Bertie Armstrong, chief executive of the Scottish Fishermen's Federation (SFF), said problems would arise as soon as a fishing boat reaches its quota limit for a particular species.

He said that, for example, a boat that had reached its annual limit for haddock landings would continue to pick up haddock as it trawled for other species, as it is not possible to completely avoid haddock while targeting cod, monkfish or whiting.

Unless the rules are either changed or implemented flexibly, it could mean a boat had to stop fishing completely once it had reached its quota for one species, regardless of how much unused quota it still had for other fish.

Armstrong said: "If fishing boats are forced to land the fish, the question then becomes, whose quota does it come off? It is an unanswered conundrum. If we don't find a ­solution the European fishing industry will collapse."

The SFF has raised the question repeatedly with the EU, the UK and Scottish fishing authorities, but said it has not received a satisfactory reply.

The first phase of the discards ban - technically known as the landings obligation - which comes into force from January 1, 2015, is not expected to create problems for Scottish fishermen, as pelagic fish swim in shoals and catches are rarely mixed with significant quantities of other species.

But Armstrong warned that if no solution to the problems with mixed whitefish is found within the next 12 months, the Scottish fishing ­industry - as well as large swathes of the ­fishing industry elsewhere in the EU - could be seriously damaged.

The SFF is pressing for a solution at next month's EU fisheries council in Brussels, where the rules for 2015 will be set.

Last month, in line with scientific advice from the International Council for the Exploration of the Sea (ICES), the European Commission proposed reducing the total allowable catch in the Atlantic and North Sea for 40 species in 2015 and increasing it for 29 species.

The commission's proposal would see no change in the zero catch for west of Scotland cod or in the quota for North Sea megrim (a flatfish also known as whiff). But North Sea cod faces a 10% cut while west of Scotland whiting faces a 20% cut.

The proposed cut to the North Sea cod quota is being opposed by the SFF as the organisation believes that cod stocks have now significantly ­recovered in recent years. Armstrong said that if EU fishing ministers agree big quota cuts next month, there was a danger they would "kill the patient with the medicine" in an attempt to boost fishing stocks.

He said: "There are some real threats to the industry and these need to be dealt with very carefully indeed."

The discard debate has been rumbling on for years as previous versions of the EU's Common Fisheries Policy gave fishermen little alternative to throwing edible fish overboard in order to meet strict quotas. In 2009, the system forced Scottish skippers to discard almost 28,000 tonnes of fish valued at £33 million, which amounted to almost one-quarter of Scotland's whitefish catch.

The EU's decision to outlaw the practice was, at least partially, in response to the public outcry in the UK to campaigns such as Fish Fight led by celebrity chef Hugh Fearnley-Whittingstall.

Although the practice of ­discarding has, in the past, been criticised by environmental groups, a ­Strathclyde University study earlier this year found that a ban on discarding healthy fish could harm the marine ecosystem, as wildlife such as seabirds, marine mammals, seabed animals and other fish have become accustomed to feeding on discards.