Scotland's whitefish stocks have a "bright future" if threatened species are given greater protection, WWF Scotland has said.
The wildlife conservation body has published its latest assessment of the state of the main species harvested.
WWF Scotland welcomed progressive measures to conserve stocks.
But it warned that the amount of haddock being dumped off the west of Scotland because they were too big, or too small, was "unacceptably high".
The organisation also called for better scientific knowledge of monkfish, a relatively new species taken by the Scottish whitefish fleet.
It said its end-of-year assessment drew on the latest scientific information, stock management plans and European Commission announcements on catch quotas.
WWF Scotland's marine policy officer, Dr Mireille Thom, said 2010 had been a year of ups and downs for many fish stocks.
She said North Sea stocks were in a better shape than those off the west of Scotland.
Dr Thom said: "Conservation measures taken by the industry have been rewarded in the North Sea, where the haddock fishery gained Marine Stewardship Council certification.
"However, despite progressive measures being taken in Scotland to protect cod, including the use of more selective fishing gear and CCTV on board a number of vessels, North Sea cod stocks have not yet recovered enough to avoid new cuts in quotas."
She added: "Scotland's fishing industry is part of the fabric of the nation and has a profitable future ahead of it, but only if long-term conservation measures are strengthened and the European Common Fisheries Policy undergoes an effective reform along more sustainable lines."
Earlier in December, Scottish fishermen said they were facing deep cuts in catch quotas after European Union talks in Brussels.
The west coast was hardest hit, with 25% reductions in catch sizes for cod, haddock and whiting.
There were some successes for the Scottish negotiating team, with proposed reductions to other species scaled back.
The Scottish Fishermen's Federation (SFF), which has an environmental policy statement aimed at encouraging sustainable fishing, has called for reform in the way Scotland's fisheries are managed.
Chief executive Bertie Armstrong said the SFF and WWF Scotland were singing from the same hymn sheet.
He said: "They have firmly recognised the actions taken by the Scottish fishing fleet.
"Also we are pleased that they have noted that fishing is part of the fabric of the coastal areas of Scotland.
"There are a couple of areas of difference, but you would expect that."
Mr Armstrong said the conservation group's recommendation for tighter restrictions on haddock catches off the west coast were being addressed in a management plan with the Irish fleet.