Aquaculture is now the second most valuable food producing sector in rural Scotland after beef - even though it is producing less salmon than four years ago.

According to the Aquaculture Information Bureau, the sector is worth more than £400m, behind beef at £467m and ahead of fish at £370m, lamb at £151m and the pig industry at £57m.

Farmed salmon output was 169,000 tonnes in 2003 and today stands at 142,000 tonnes. Farmers are achieving higher prices by focusing on premium and added-value lines, and avoiding commoditisation.

Farmed fish and shellfish represent 50% by value of all Scottish food exports.