Scottish Sea Fisheries Statistics 2011

A detailed overview of landings of sea fish; the Scottish fishing fleet; and the number of sea fishermen employed.

Annex 1: Methodology


Scottish Sea Fisheries Statistics are obtained by simple data extractions from the FIN (Fisheries Information Network) administrative data base containing information on sea fishing activity and catch details, including sales details from Registered Buyers and Sellers ( RBS), input by Marine Scotland Compliance, based on information supplied by fishing vessels, buyers and sellers. Where necessary, this is supplemented by information from the equivalent "Rest of UK" administrative system, FAD, using data held in the UK data warehouse, IFISH.

Voyage and landings information is supplied by skippers who, for vessels over 10 metres, are required by EU legislation to maintain logbooks and provide landings declarations (see Glossary). Although this EU legislation does not require vessels of 10 metres and under to provide this information; in Scotland they provide equivalent information on the NEP1 and SHELL1 returns. Data on first sales of fish, which provides information on the value of landings, is provided by fish buyers and sellers under EU legislation on the Register of Buyers and Sellers (see Glossary). The information submitted forms the basis for reports to the Commission to meet the obligations of the EU legislation. The relevant legislation is listed in the Statistical Plan for Sea Fisheries statistics - see link below:

Information is collated and entered at port offices on to the FIN central server.

For four of the tables in the Statistical Bulletin, information from FIN/ IFISH is supplemented by information obtained through an aggregate return distributed to port offices in each of the 18 Scottish fishing districts on the numbers of fishermen employed on the vessels in each creek administered by that port office. The burden on respondents for this small survey is estimated to total no more than £1 thousand each year, based on information obtained from each office on the time taken to complete the return and the grades of staff involved. In two of the tables, this information is compared with very summary information on the labour force obtained from the Labour Force Survey.

Uses made of the statistics

The main driver for the collection of the information on sea fisheries is the need to produce reports to the EU Commission to meet the obligations of the relevant EU legislation. Because most use made by internal users is of the underlying management information, providing on-going monitoring of sea fishing such as quota and effort uptake, the main use made of the published statistics is by external users or information designed eventually for external users such as the Fish Producer Organisations.

The main macro-level use for the information is the assessment of the value of sea fishing to Scotland, either in total or in specific sea areas. There is also a degree of political and media interest in the trends in the numbers of fishing vessels and numbers of fishermen employed, particularly in the context of two major decommissioning schemes in the early 2000's. Scottish Parliament researchers use the information in briefings prepared on fisheries for MSPs and the Rural Affairs and Environment Committee. The published statistics are also used in the construction of the Scotland Performs Indicator #44 on fish stock sustainability - see links below

The major micro-level use made by external users requesting specific data is to examine sea fishing activity in small areas of the sea around Scotland as input to environmental impact assessments for off-shore energy (oil and renewable energy sources) developments.


Because of the use of the management information in supplying reports to the EU Commission and stakeholders in uptake of fish quotas and days at sea, the information in the administrative data bases is subject to thorough and extensive automated vet checking at the micro level at the point of data input by Marine Scotland Compliance Port Offices. This is supplemented by quality assurance work by the Data Team throughout the year to ensure consistency between the two vessel file administrative data bases and checks for missing returns of landing declarations. Furthermore, stakeholders make representations to get data corrected if they assess that it does not correctly reflect their catch of quota stocks or usage of days at sea.

The main issue for the quality of the published statistics is the completeness of coverage of the information in the administrative systems as, particularly for catch of fish species not subject to quota, it can take some time for the information to be input into the relevant administrative data bases. It is for this reason that provisional statistics are not published until about 3-4 months after the year to which they relate and the final statistics are published about 9 months after the year to which they relate. We assess that some 0.2% of landings (by value) of Scottish vessels are omitted from the final published statistics each year, mainly due to delays in receipt of information on landings outwith the UK. However, this small incompleteness does not affect the trends shown by the statistics. Although the provisional figures are not published until coverage of quota stocks is reasonably complete, information on non-quota stocks remains less complete. The table below summarises the change between the provisional and final statistics by species type for landings of Scottish vessels. (Shellfish species other than Nephrops are not subject to quota.)

Increase in recorded landings by Scottish vessels since provisional statistics

Species type 2010 Provisional Statistics 2010 Statistical Bulletin % increase
Live weight Value Live weight Value Live weight Value
(000 tonnes) (£m) (000 tonnes) (£m) (000 tonnes) (£m)
Demersal 105.5 152 105.9 152 0.34% 0.08%
Pelagic (1) 188.6 124 189.1 129 0.29% 4.12%
Shellfish 71.8 152 72.4 154 0.82% 1.15%
Total 365.9 428 367.4 435 0.40% 1.62%

(1) Much of the increase in the recorded value of Pelagic landings is due to improvements since the provisional statistics in the price data recorded for mackerel landed abroad

The Introduction of the Buyers and Sellers legislation in September 2005 made a change in how the information on the value of landings was captured into FIN. Previously, this information had been directly entered by Port Offices using their local knowledge on prices obtained. This information is now derived from the Sales Notes submitted, with automatic data processing matching the information from the landing declaration with the values obtained for that landing as covered in the relevant Sales Notes. However, Sales Notes are not submitted for all landings. Firstly, Sales Notes were not required for shellfish sales between September 2005 and February 2006, to allow a grace period for fishermen to adapt to the new legislation. Furthermore, Sales Notes are still not required to be submitted for UK vessels landing into non- EU countries. In such cases the value of the landings is estimated, using an automated process which, in the absence of Sales Notes information, applies for each species the available information on average prices obtained in the preceding quarter to the weight of landings as submitted in the landing declaration.

Investigation of an apparent sharp decrease between 2009 and 2010 in the prices obtained by Scottish vessels landing mackerel abroad revealed that, as no Sales Notes had been received for such landings into Norway, the information had been estimated, as described above. The fall in prices was due to a decrease in the average price obtained by all vessels for mackerel between Q4 2009 and Q3 and Q4 2010. We received specific data from Norway on the weight and value of mackerel landings from Scottish vessels and these yielded the actual prices obtained for these landings. This information does not show the decrease in price observed for all mackerel landings. Proxy Sales notes for the 2010 landings were then created by the Port Offices concerned and they were then input into FIN, which explains some of the increase in the figures for the value of Pelagic landings between the provisional statistics and those presented in this Bulletin. Unfortunately, this was not possible for the 2009 landings and these have then continue to impute value using the average prices observed, which were considerably higher (20% - 70%) than those actually obtained for the Norwegian landings. In consequence, we now estimate that the value of landings by Scottish vessels obtained in 2009 are overstated by some £7 million, making the value landed in 2009 £436 million, rather than the £443 million shown. Nevertheless, this overstatement does not affect the general trends and the value landed in 2009 is still the highest in the decade, even after this overstatement has been allowed for.

Another issue for the quality of the statistics is that, perforce, they can only reflect the information supplied by the fishermen on their activity and catch. The detailed extensive automated vet checking carried out at the data input stage can only check internal consistency of the information supplied. The introduction of the Buyers and Sellers legislation provides an external check on the declared landings of fish and undeclared ("black") landings are now assessed by Marine Scotland Compliance as being at negligible levels [cf: Scottish Fisheries Protection Agency annual report and accounts 2008/2009]. Also, for vessels of 15 metres and over, the introduction of the Vessel Monitoring System provides a check on the location of fishing activity recorded in fishermen's log books. These checks are supplemented by activity of Marine Scotland Compliance. However, it cannot be assumed that reporting by fishermen is invariably accurate.

Revisions to the published statistics

The statistics for previous years published in the Statistical Bulletin are not amended for small changes (in the order of 0.2%) due to late data entry/amendment, as these do not affect the main trends presented - see above. On the rare occasions that such revisions are required due to the discovery of errors in the previously published figures which affect the main trends presented, the revised figures are marked "(r)" and suitably footnoted to explain the reason for the revision. Clearly, the statistics are revised between the published provisional statistics and those published in the Statistical Bulletin - see above table for an indication of the differences. However, provisional statistics are always explicitly identified as such.

The format of the tables presented in this Statistical Bulletin have been extensively revised, following a review of the Bulletin. Although figures for years before 2010 were derived from essentially the same data sources, there are a handful of cases where the figures do not agree exactly with those previously published. The differences, however, are trivial; with differences in the order of magnitude of tens between figures of the orders of tens or hundreds of thousands and do not have any bearing on the trends or the statistics' fitness for purpose. These figures are consequently not described as revised.

Comparability with other UK countries

Because the same EU legislations covers information requirements for vessels over 10 metres and for all buyers and sellers, the information derived from these data providers is comparable for all countries within the UK, as it is for all EU countries. The only difference between information collated in Scotland and that collated in the rest of the UK is that, through the NEP1 and SHELL1 returns, Scotland obtains equivalent information on a full coverage basis for vessels of 10 metres and under. In the rest of the UK, this information is provided on a sample basis only. However, because the vast majority of fish are caught by vessels over 10 metres, the information is effectively comparable for all UK countries, in spite of this difference in information capture for the 10 metre and under vessels.


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