SCOTLAND is contributing to a marine "crisis" in which 40 per cent of fish caught across the world is discarded or comes from unsustainable sources, according to a report.
More than 38 million tonnes of fish caught globally can be defined as by-catch, according to the paper co-authored by conservation charity WWF.
The authors came up with a new definition of by-catch, to include fish from unmanaged stocks, as well a
s those that end up being unused.
It puts levels of by-catch up to five times higher than previous estimates, which have ranged from seven to 27 million tonnes annually.
The report estimated by-catch levels in the north-east Atlantic were as high as 20 per cent due to "extremely high discard rates".
The report, Defining and Estimating Global Marine Fisheries By-catch, said: "Many north-east Atlantic fisheries have extremely high discard rates, particularly from the bottom-trawling fleet, which generates far more by-catch than marketable fish."
WWF Scotland suggested this was due to factors such as use of non-selective fishing gear, market demands and quota limitations.
Amanda Nickson, leader of WWF's By-catch Initiative and co-author of the paper, said: "The health of our oceans cannot be restored or fisheries sustainably managed if 40 per cent of the global catch is unused or unmanaged.
"A huge quantity of fish and marine animals are thrown back into the sea dead or dying. Even if this by-catch is retained, there is no way of telling whether it was sustainable to remove it from the sea in the first place."
Scottish environment secretary Richard Lochhead said Scotland's commitment to tackling the by-catch issue was "unrivalled across Europe". He added: "While any solution to this economic and environmental madness must involve Europe, the Scottish Government, backed by fishermen, conservationists and scientists, stands ready to help find the right solution."
A spokesman for Seafish, which represents the fishing industry, said: "Anything that draws attention to the issue is welcome. No-one in this industry wants to see discards continue. We want to reduce them as much as possible."
He added that stocks of North Sea cod had been increasing since 2004.
"This is proof that conservation measures in Scotland actually work," he said.
Louize Hill, WWF Scotland's marine policy officer, urged ministers to ensure the forthcoming reform of the Common Fisheries Policy addressed the issue of by-catch "as a priority".
She praised the work already being carried out in Scotland, including closures that protect spawning fish and selective gear that allows certain species to escape the nets.
The full article contains 451 words and appears in The Scotsman newspaper.
