Three sources are used for this indicator:
1) The source for the landings data (value of catch of Scottish vessels by quota species in £million) is the annual Scottish Sea Fisheries Statistics publication, produced by Marine Scotland in Scottish Government. This is a National Statistics publication and, as such, undergo regular quality assurance reviews.
The publication is accessible on the Scottish Government's website:
Provisional figures for each year are published in April in the following year, while final data are published in September.
2) The scientific guidance comes from International Council for the Exploration of the Sea (ICES) and/or Scientific, Technical and Economic Committee for Fisheries (STECF).
Advice from ICES/STECF indicates a best practice guideline figure for TAC in tonnes for each quota stock. This information is quantitative and based on best international scientific knowledge but is not a National Statistic.
Up-to-date ICES scientific advice is published on the ICES website.
Some key Scottish commercial stocks currently lack the scientific data to allow identification of safe biological limits. Ongoing research and monitoring on those stocks should allow the identification of these limits in due course.
3) The total allowable catch limit (TAC) (expressed in tonnes) is decided by the Council of Ministers in Brussels. These data are provided by the EU.
Calculation of this indicator uses quota (Total Allowable Catch (TAC)) information and landing figures (the value of the catch) for Scotland's key commercial fish stocks. The value of those fish stocks for which the TAC was set in line with scientific guidance is summed and this total is then divided by the total value of catch for all the stocks under consideration to yield the individual year percentage.
A centred three year average is calculated as the sum of the value of those fish stocks for which the TAC was set in line with scientific guidance over each three year period divided by the total value of catch for all the stocks over the same period. This centred three year average is used as the indicator's value.
Indicator = ((value of catch landed by Scottish fishing vessels of key Scottish stocks where the TAC limit is consistent with the scientific guidance) / (total value of all the key Scottish stocks landed by Scottish vessels)) multiplied by 100, calculated on a centred three-year average.
The indicator is updated three times a year to reflect;
1) new TAC limits being set and so information becoming available on whether the TAC for each stock was set within scientific guidance (January - March),
2) publication of provisional landings data (April),
3) publication of final landings data (September).
Consequently changes in the indicator from one year to the next can occur due to changes in whether the TAC for each stock was set within the scientific guidance, and/or changes in the weightings due to use of landings data for a different year.
If final or provisional landings data for a particular year are not yet published, that year's landings data are estimated by the most recently published sea fisheries statistics.