§ Mr. SalmondTo ask the Secretary of State for Scotland if he will give details of any scientific evidence he has relating to the depletion of North Sea sandeel stocks by seals and by small herring; and if he will make a statement.
§ Mr. Lang[holding answer 16 July 1990]: Sandeels are preyed on by many predators in the North sea including, seals, seabirds and numerous other species of fish.
Published estimates for the total North sea indicate that the annual consumption of sandeels by grey seals was in the order of 35,000 to 40,000 tonnes in 1984 and 1985. An unpublished estimate for 1989 is 27,500 tonnes. There are no comparable estimates for common seals.
A rough estimate of the annual consumption of sandeels by both species of seals in the Shetland area of the North sea is in the order of 8,000 to 9,000 tonnes, which is over twice as much as the quantity taken in the fishery in 1989 and more than three times the 1990 catch.
Herring are known to prey on small sandeels at times. Research is currently being carried out by the Department of Agriculture and Fisheries for Scotland on the possible role of predation and other factors in controlling sandeel recruitment. At present, however, any link between the decrease in sandeel recruitment at Shetland and herring predation is purely speculative.