Fisheries Secretary Richard Lochhead highlighted scientific research which estimates there are about 21 million mature cod, equal to about 65,000 tonnes.

It follows reports that fewer older fish are being landed and claims there may only be 100 cod aged over 13. Officials said 60% of four-year-old cod are mature, rising to all cod by age six.

Mr Lochhead said: "The facts show that since 2006 the cod stock has been improving. Scotland has played a big part in this by achieving the EU's biggest reductions in the cod discards, while we have led the way with sustainable fishing initiatives."

Schemes such as the use of selective fishing gear to avoid catching undersized fish, help to conserve the species, he said.

"We are fully committed to ensuring a long-term future for Scottish fisheries," he said.