1 European Environment Agency DPSIR framework
Population and Households
2 Population estimates are rebased with each census to ensure a consistent time series. Estimates for 2002 to 2010 were revised using information from the 2011 Census. The population estimates from 2011 onwards are all based on the 2011 Census.
3 National Records of Scotland (2016). Mid-2015 Population Estimates Scotland.
4 National Records of Scotland (2016). Estimates of Households and Dwellings in Scotland, 2015.
5 National Records of Scotland (2015). Population Projections of Scotland (2014-based).
6 National Records Scotland (2014). Household Projections for Scotland (2012 based).
7 National Records of Scotland (2015). Scotland's Population 2015 - The Registrar General's Annual Review of Demographic Trends
Gross Domestic Product
8 The estimates from the Scottish Government's Quarterly GDP Publication measure GDP at basic prices,
also referred to as Gross Value Added (GVA), which does not account for taxes or subsidies on products.
The GDP index is produced in constant (2013) prices, meaning that the effect of price changes is removed
from the estimates, and is seasonally adjusted.
Motor Traffic on All Roads
9 Salisbury, E., Thistlethwaite, G., Pang, Y., & Misra, A. (2015). National Atmospheric Emissions Inventory (2015). Air Quality Pollutant Inventories for England, Scotland, Wales and Northern Ireland: 1990 - 2013.
10 More information is available in Transport and Travel in Scotland 2015 and Scottish Transport Statistics 2015.
11 Scottish Government. Scotland's People Annual Report: Results from 2014 Scottish Household Survey.
12 Department for Transport. Vehicle Licensing Statistics: 2015.
Electricity Generation by Source
13 Includes wind, wave, solar power, thermal renewables and hydroelectric (natural flow).
14 Pumped storage is not a renewable source of energy because it uses electricity produced by other means to create a store of hydrological power.
15 Scottish Government (2009). Climate Change (Scotland) Act 2009.
16 The Scottish Government has set a target for renewable sources to generate the equivalent of 100% of Scotland’s gross annual electricity consumption by 2020, with an interim target of 50% set for 2015.
17 The amount of electricity generated minus net exports (but including losses).
18 Scotland Performs. National Indicator: Improve access to local greenspace.
19 Scottish Government Social Research (2009). Scottish Environmental Attitudes and Behaviours Survey 2008 (SEABS ’08)
20 Scotland Performs. National Indicator: Increase people's use of Scotland's outdoors.
21 Climate Change 2014: Synthesis Report, Intergovernmental Panel on Climate Change (IPCC), 2014.
22 Climate Change (Scotland) Act 2009.
23 Climate Change (Annual Targets) (Scotland) Order 2010 (2010-2022)
24 Climate Change (Annual Targets) (Scotland) Order 2011 (2023-2027)
25 Scottish Government (2015). Sustainability Purpose Target
26 Scottish Government (2015). Scotland Performs National Indicator 47: Reduce Scotland’s Carbon Footprint
Annual Mean Temperature
27 The 1961-1990 averages used in this publication are calculated from 5 km grid squares and differ from the averages published by the Met Office which are based upon 1 km grid squares. The average used is temperature = 7.03°C. Although 1971-2000 and 1981-2010 averages are available, 1961-1990 averages are used for comparability with UK Climate Projections 2009 (see next).
28 UK Climate Projections 2009. The projected changes, based on the 1961-1990 averages, use the medium emissions scenario climate model, and are for the 2080s, i.e. a 2071-2100 average. The Scottish regions are North, West and East Scotland, based on Met Office climate regions.
29 Climate Change 2014: Synthesis Report, Intergovernmental Panel on Climate Change (IPCC), 2014.
30 The 1961-1990 averages used in this publication are calculated from 5 km grid squares and differ from the averages published by the Met Office which are based upon 1 km grid squares. The average used is precipitation = 1,390.57 mm. Although 1971-2000 and 1981-2010 averages are available, 1961-1990 averages are used for comparability with UK Climate Projections 2009 (see next).
31 UK Climate Projections 2009. The projected changes, based on the 1961-1990 averages, use the medium emissions scenario climate model, and are for the 2080s, i.e. a 2071-2100 average. The Scottish regions are North, West and East Scotland, based on Met Office climate regions. For each estimate, the smallest 10% probability level and the largest 90% probability level as well as the most likely estimate are given, to show the spread of possible outcomes.
32 For example, projected changes in the East of Scotland are reduced precipitation of 17% (-33% to 0%) in the summer months (June to August) and an increase of 12% (1% to 25%) precipitation in winter months (December to February).
33Winter and summer precipitation figures are available on Scottish Environment Statistics Online.
34 Climate Change 2014: Synthesis Report, Intergovernmental Panel on Climate Change (IPCC), 2014.
Greenhouse Gas Emissions by Sources
35 Emissions of each GHG are weighted by the global warming potential ( GWP) of the gas. GWP accounts for the potency of the gas as a contributor to atmospheric warming. Therefore, while sulphur hexafluoride is released in small quantities, those emissions are adjusted to better reflect the strong warming effect it has. GWPs of all gases are expressed as tonnes of carbon dioxide equivalent to permit ready comparison.
36 For the purposes of reporting, greenhouse gas emissions are allocated into sectors. The Official Statistics release “ Scottish Greenhouse Gas Emissions 2014” contains a categorisation of each sector.
37 Emissions from offshore oil and gas installations are not included in the Scottish inventory, and are reported as “unallocated” within the disaggregated UK inventory.
38 IPCC Fifth Assessment Report 2013.
Scotland’s Carbon Footprint
39 Emissions of each GHG are weighted by the global warming potential ( GWP) of the gas. GWP accounts for the potency of the gas as a contributor to atmospheric warming. Therefore, while sulphur hexafluoride is released in small quantities, those emissions are adjusted to better reflect the strong warming effect it has. GWPs of all gases are expressed as tonnes of carbon dioxide equivalent to permit ready comparison.
40 The Carbon Footprint is part of a small set of low carbon attitude and behaviour-related indicators set out in ‘ Low Carbon Scotland: A Behaviours Framework’ and is used to inform the Scottish Government National Indicator Reduce Scotland's carbon footprint.
Column Ozone Measurement
41 Stratospheric ozone is not the same as tropospheric (ground level) ozone, which is a damaging oxidant.
42 United Nations Environment Programme. Montreal Protocol.
43 Through analysis of modelled background PM2.5 concentrations (particles less than 2.5 µm in diameter), it is estimated that the effects on annual mortality in 2010 in Scotland were over 2000 deaths and over 22,000 associated life-years lost. (Public Health England (2014). Estimating local mortality burdens associated with particulate air pollution.
44 Department for Environment, Food and Rural Affairs, Scottish Executive, Welsh Assembly Government & DOE Northern Ireland (2007). The Air Quality Strategy for England, Scotland, Wales and Northern Ireland Volume 1.
45 Reproduced by permission of Ordnance Survey on behalf of HMSO. © Crown copyright and database right 2015. All rights reserved. Ordnance Survey Licence number 100024655. Scottish Government GI Science & Analysis Team, August 2015, Job5706ab
Emissions of Air Pollutants
46 PM10 - particulate matter smaller than 10 microns.
Emissions of Sulphur Dioxide and Nitrogen Oxides from Large
47 Large combustion plants have a rated thermal output of over 50 megawatts. In 2015, there were 45 LCPs in Scotland, down from 52 in 2014.
48 The Large Combustion Plants Directive (LCPD), which has now been incorporated into the Industrial Emissions Directive (2010/75/EC), called for a 60% reduction in LCP SO2 emissions by 2003 and a 30% reduction in LCP NOx emissions by 1998, from a 1980 baseline. By 2012, total UK emissions of SO2 were 91% below 1980 levels and total UK emissions of NOx were 60% below 1980 levels, according to the Department for Environment, Food and Rural Affairs Environment Statistics website.
49 All values displayed in the chart are at or above the 50% data capture rate. If the data capture rate for any site is below 50% then the data will not be included in the chart. Where this occurs, information will be provided as appropriate in further footnotes. When assessing whether sites met the Air Quality Strategy objectives, only those sites with a data capture rate of at least 75% are included.
50 The data capture rate was low (under 50%) for Glasgow Centre in 2010 and so will not be included in any charts or tables. The 2010 figure for Glasgow Centre is: PM10 = 23.
51 This chart contains an illustrative sample of automatic monitoring sites which have been selected based on their geographical location, how long they were in operation, site type (generally ‘kerbside sites’ are not included) and whether there were consistently high data capture rates. This is mainly to allow the data to be presented clearly, as there are too many monitoring sites to clearly present in one chart. The overall trends are discussed in the ‘Trend’ section.
52 National Atmospheric Emissions Inventory (2016). Air Quality Pollutant Inventories for England, Scotland, Wales and Northern Ireland: 1990 - 2014.
53 In 2015, PM10 concentration was measured at 76 automatic monitoring sites in Scotland, 64 of which had a data capture rate of at least 75%. Of the sites with data capture under 75%, none exceeded the 40 µg/m3 UK AQS. Data for these sites are available on the Scottish Air Quality Database.
54 Edinburgh Salamander Street is not included in the chart as it did not meet the criteria for inclusion.
Nitrogen Dioxide Concentrations
55 All values displayed in the chart are at or above the 50% data capture rate. If the data capture rate for any site is below 50% then the data will not be included in the chart. Where this occurs, information will be provided as appropriate in further footnotes. When assessing whether sites met the Air Quality Strategy objectives, only those sites with a data capture rate of at least 75% are included.
56 The data capture rates were low (under 50%) for Glasgow City Chambers and Glasgow Byres Road in 2011 and for Aberdeen Errol Place in 2013; therefore, these figures will not be included in any charts or tables. The 2011 figures for Glasgow City Chambers and Glasgow Byres Road are NO2 = 50 and NO2 = 42 respectively; and the 2013 figure for Aberdeen Errol Place is NO2 = 20. In 2015, a sampling fault led to all NO2 data for Edinburgh St Leonards being rejected.
57 This chart contains an illustrative sample of automatic monitoring sites which have been selected based on their geographical location, how long they were in operation, site type (generally ‘kerbside sites’ are not included) and whether there were consistently high data capture rates. This is mainly to allow the data to be presented clearly, as there are too many monitoring sites to clearly present in one chart. The overall trends are discussed in the ‘Trend’ section.
58 In 2015, concentrations of nitrogen oxides were measured at 79 automatic monitoring sites in Scotland. Of these sites, 70 had a capture rate of at least 75% - data for these sites can be found on the Scottish Air Quality Database.
59 These sites were not included in the chart as they are both ‘Kerbside’ sites.
60 National Atmospheric Emissions Inventory (2016). Air Quality Pollutant Inventories for England, Scotland, Wales and Northern Ireland: 1990 - 2014.
Ground Level Ozone
61 All values displayed in the chart are at or above the 50% data capture rate. If the data capture rate for any site is below 50% then the data will not be included in the chart. Where this occurs, information will be provided as appropriate in further footnotes. When assessing whether sites met the Air Quality Strategy objectives, only those sites with a data capture rate of at least 75% are included.
62 This chart contains an illustrative sample of automatic monitoring sites which have been selected based on their geographical location, how long they were in operation, site type (generally ‘kerbside sites’ are not included) and whether there were consistently high data capture rates. This is mainly to allow the data to be presented clearly, as there are too many monitoring sites to clearly present in one chart. The overall trends are discussed in the ‘Trend’ section.
63 In 2015, ozone concentrations were measured at 11 sites, which all had a data capture rate of over 75%. Data for these sites are available on the Scottish Air Quality Database.
Sensitive Habitats Exceeding Critical Loads for Acidification and Eutrophication
64 3-year average deposition is used to reduce substantial year to year variability. Deposition data for 1995-97 to 1999-01 are based on the same methodology. Changes have subsequently been made to the methods for estimating deposition: (i) nitric acid deposition has been included in data from 2001-03 onwards; (ii) aerosol deposition of NH4, NO3, SO4 has been included in data from 2002-04 onwards. Therefore deposition for earlier years may be underestimated and so the actual reductions may be larger than shown here.
65 Deposition data sets for 2004 to 2013 have been updated following research by NERC, CEH and Defra (report under review), which assessed the current DELTA sampler configuration’s specificity for HNO3 measurement and showed additional sampling of other atmospheric oxidised nitrogen species. A correction factor has been obtained and applied to the HNO3 concentrations used in the CBED mapping and the trends in critical loads exceedances for the period 2004-06 to 2011-2013 have been updated accordingly.
66 Hall, J., Curtis, C., Dore, T., Smith, R. 2015. Methods for the calculation of critical loads and their exceedances in the UK. Report to Defra under contract AQ0826. Centre for Ecology and Hydrology.
67 Hall, J., Smith, R. 2015. Trends in critical load exceedances in the UK. Report to Defra under contract AQ0826. Centre for Ecology and Hydrology.
68 Eutrophication is the accelerated growth of plants in water bodies caused by excess nutrients. This accelerated growth and subsequent decay of plant organisms depletes oxygen levels, which can have harmful effects upon fish and other aquatic life which require oxygen to survive.
69 Drinking Water Quality Regulator for Scotland (2001). The Water Supply (Water Quality) (Scotland) Regulations 2001.
Public Water Supplies
70 Figures for the raw water abstracted are collected over the calendar year, as it is part of the corporate data submitted to SEPA, whereas treated water produced data is collected over the business reporting year (April to March). Therefore, to present both sets of data on the same chart, the raw water abstracted figures shown reflect the first part of the business reporting year. For example, this means that the figure for 2015/16 reflects the raw water abstracted in 2015.
71 Since 2010, raw water abstracted has been based on metered data. Prior to 2010, it was estimated based on a calculated methodology. Slight corrections were made to the 2007 and 2008 figures in 2010.
72 Operational use includes standpipe volumes, fire service use, hydrant misuse, void property use, as well as use by Scottish Water in Offices, waste water treatment works, the distribution network and sewer jetting.
73 Total Top Down Leakage is the summation of Scottish Water distribution network losses and customer supply side leakage, as calculated using ISO9001 Water Balance methodologies. This method is different than the one used to calculate the leakage figure included in the annual Water Industry Output Monitoring Group report and as such, the figures differ slightly each year.
74 The Economic Level of Leakage ( ELL) (where the cost of repair is greater than the value of water leaking from the system) was attained in 2012/13, and leakage has continued to be managed at this level since.
Drinking Water Quality
75 Drinking Water Quality Regulator for Scotland (2001). The Water Supply (Water Quality) (Scotland) Regulations 2001.
76 Drinking Water Quality Regulator for Scotland. DWQR Annual Report
River Water Quality
77 The indicator is based on a set of five water quality parameters which are sensitive to organic pollution, nutrients and toxic substances and provide a measure of species diversity. Each of the parameters is assessed over a rolling 3 year period and the results weighted by river length. The assessment is against the standards provided for each parameter in the Water Framework Directive classification. Two of the Water Framework Directive standards, invertebrates and phosphorus, used to calculate the indicator were changed in 2013; SEPA is looking into back calculating the indicator values potentially as far back as 2007 using the new standards to provide a consistent time series.
78 Data are expressed as mg N/l. To convert to mg NO3/l (nitrate), multiply by 62/14.
79 This applies to most European rivers though for some rivers up to 1 mg N/l is
reported. See European Environment Agency report 'Nutrients in Fresh Water'. for more information.
80 In Aberdeen, Moray, Banff and Buchan; Strathmore and Fife; Lothians and Borders; Lower Nithsdale and Stranraer Lowlands.
81 Under The Designation of Nitrate Vulnerable Zones (Scotland) Regulations 2002 and The Designation of Nitrate Vulnerable Zones (Scotland) Regulations 2015 and EC Nitrates Directive (91/676/EEC) Annex 1A(3).
82 Soluble reactive phosphorus was measured as μg P/l. To convert to μg PO4/l (orthophosphate), multiply by 95/31.
Compliance with the EC Bathing Water Directive
83 The number of bathing waters identified in Scotland has not remained constant in the period 2000-2016. There were 60 identified bathing waters in 2000, two of which were inland bathing waters, rising to 84 in 2013. Three of the 84 designated bathing waters are inland waters, which have all complied with the bathing water standards since designation.
Sources of radioactivity
86 Radon and gamma values are specific to Scotland. Other values are assumed to be the same as the UK average as published in the Health Protection Agency - Radiation Protection Division’s publication: HPA-RPD-001 - Ionising Radiation Exposure of the UK Population: 2005 Review.
87 Because of rounding, percentages do not add up to 100.
Radioactivity in milk
88 From 1996 onwards, the concentrations reported were lower than the limit for detection. Note that figures pre-1996 were produced by the HPA who took milk samples from a number of milk depots throughout the country, in proportion to the quantity of milk handled by each depot in order to generate the data. Post-1996 the figures were produced by SEPA who collected samples and analysed them for sites remote from nuclear sites. As a result, the 1996-2014 figures are not strictly comparable with previous years, although they still represent average concentrations in milk in Scotland.
89 Unlike 137Cs, which was widely dispersed in the environment, 90Sr was mostly deposited near Chernobyl.
Waste and Recycling
90 European Waste hierarchy
91 Scottish Government. Making things last - A circular economy strategy for Scotland.
92 Scotland Performs. National Indicator: Reduce waste generated.
93 SEPA waste data technical report
94 In 2011 the meaning of household waste changed to mean “waste from households” only. Waste which had previously been reported in WasteDataFlow as household waste includes street sweeping, litter bins, parks and gardens waste, and beach cleaning waste. From 2011, combustion of household waste outputs which previously counted as recycled are now included in the Other Diversion category. This includes incinerator bottom ash and metal outputs from incineration. Household waste used to produce compost like outputs from mechanical biological treatment plants also no longer contribute to recycling.
95 Scotland's Environment Website - interactive household waste data
96 Scotland’s Environment Website - Land.
97 Scotland's Environment Website - Land - Woodlands and Forests.
98 © Crown copyright and database right 2014. Ordnance Survey Licence number 100021242.
99 Scotland Performs Greener Objective.
100 Scottish Government. Land Use Strategy.
101 Forestry Statistics 2016.
102 Scotland Performs. National Indicator: Increase people's use of Scotland's outdoors.
103 Scotland Performs. National Indicator: Improve the condition of protected nature sites.
104 Scottish Government. Land Use Strategy indicators.
Derelict and Urban Vacant Land
105 During 2015, historical data for the years 2009 - 2014 were revised to remove sites that had been taken out of the survey for definitional reasons and to correct any other previous errors highlighted in the 2015 survey returns.
106 Vacant land must either have had prior development on it, or had preparatory work taken place on it in anticipation of future development to be classed as ‘vacant land’. Derelict land must currently not be used for the purpose for which it is held or a use acceptable in the local plan to be classed as ‘derelict land’. Land also qualifies as derelict if it has an un-remedied previous use which could constrain future development.
Agricultural Land Use
107 Changes in trend may reflect changes to the coverage of agricultural holdings included in the June Census register, as well as genuine changes in the area of total agricultural land.
108 Scotland’s Environment Website - Land.
109 From 2009, data on land use was obtained from the Single Application Form ( SAF). This data has been combined with the land use data from all other holdings, collected through the June Agricultural Census Forms, to generate overall June Agricultural Census results. This development has led to a substantial reduction in statistical data collection and an overall improvement in the quality of land use statistics. The use of SAF data has resulted in a step change in some of the land use results from 2009, especially for rough grazing and grass. This means that the trends across 2008 and 2009 for these land use categories represent differences in the way this data has been reported between the 2008 June Agricultural Census and 2009 SAF rather than genuine changes and so should be treated with caution.
110 In 2015 and 2016, changes to the SAF meant that land use data was not available for about 500,000 ha of rough grazing, woodland, and other land. These were estimated based on previous years. In 2016 this affected 1% of rough grazing, 75% of woodland and 86% of other land. This is in addition to the usual estimation for non-SAF respondents not returning a census.
111 Only includes woodland on agricultural holdings.
Nutrients Applied to Crops and Grass
112 Total quantity of nutrient used (kg) divided by the total extent of crop area (ha) (including any areas without application of the nutrient). These overall application rates provide a means of estimating the tonnage of nutrients from manufactured fertiliser used during the year.
113 Manufactured fertilisers only - excludes organic fertilisers such as manure and slurry or sewage sludge.
Area of Woodland
114 Woodland is defined as land under stands of trees with a canopy cover of at least 20%, or having the potential to achieve this, including integral open space, wooded agricultural land, and felled areas that are awaiting restocking.
115 Restocking is the replanting of existing areas of woodland that have been felled. This includes felled areas that have been restocked by natural regeneration.
116 Marine Scotland. National Marine Plan Interactive.
117 Figures as at 31 March each year.
118 Area figures are rounded to the nearest thousand hectares and percentages to the nearest whole number. Area figures exclude the area in England of cross-border sites. Figures for SACs and SPAs include both terrestrial and marine areas. Figures for SSSIs include intertidal habitats.
119 Many protected areas may be covered by more than one conservation designation. In particular, SSSIs overlap to a considerable extent with other designations. About 65% of terrestrial/inshore SACs, 52% of SPAs, and 86% of Ramsar Sites by area are also designated as SSSIs.
120 In Scotland, SSSIs are designated by Scottish Natural Heritage under the Nature Conservation (Scotland) Act 2004. Some SSSIs overlap and where this occurs the area of overlapping land will be counted more than once. In 2016 this accounted for 2,708 hectares, so the net area of SSSI sites at 31 March 2016 is approximately 1,019,648 hectares.
121 Special Areas of Conservation ( SACs) are designated under the 1992 EU Habitats Directive to protect certain species and habitat types throughout the EU. Some SACs overlap, and where this occurs the area of overlapping land will be counted more than once. In 2016 this accounted for around 5,500 hectares, so the net area of SAC sites at 31 March 2016 is approximately 981,100 hectares. Figures include both designated SACs and candidate SACs submitted to the EC. Figures included in the Offshore Marine category include 2 candidate SACs that straddle the 12 nm inshore/offshore marine boundary.
122 Special Protection Areas ( SPAs) are classified under the 1979 EU Wild Birds Directive (which was codified in 2009) to safeguard the habitat of certain wild bird species. Some SPAs overlap, and where this occurs the area of overlapping land will be counted more than once. In 2016 this accounted for around 58,500 hectares, so the net area of SPA sites at 31 March 2016 is approximately 1,237,700 hectares.
123 Ramsar sites are designated under the 1971 Convention on Wetlands of International Importance (commonly known as the Ramsar Convention).
124 Figures as at 31 March each year.
125 UK Parliament (1979). Ancient Monuments and Archaeological Areas Act 1979.
126 Further information about SMs, including maps, is available on the Historic Environment Scotland portal: http://portal.historicenvironment.scot/spatialdownloads.
127 The designations team within Historic Environment Scotland compiles and maintains the ‘Schedule’ of monuments of national importance.
128 The review of dual designated sites is a nationwide project to review structures which are both listed as buildings of special architectural or historic interest and scheduled as monuments of national importance. Where appropriate the ‘dual designation’ of structures is being removed and they are being either listed or scheduled depending on their individual circumstances. Removing dual designations will help to provide clarity for the future management of sites. Overall it will see a reduction in the number of designations, but not a reduction in the number of sites that are designated.
Percentage of natural features on protected sites in
129 Scottish Natural Heritage's Site Condition Monitoring ( SCM) programme is a six-year rolling programme of monitoring which aims to assess the condition of, and management/wider environmental influences on, a sample of designated natural features each year. Sites classed as being in favourable condition include sites assessed as being in favourable condition through SCM, sites assessed as being in unfavourable condition but showing signs of recovery and sites assessed as being unfavourable but benefitting from a change in management measures which, given an appropriate time, will ensure the feature reaches favourable condition.
130 Scottish Natural Heritage. Site Condition Monitoring (SCM) programme. SCM data is also available via Scotland’s Environment Web.
131 Scotland Performs. National Indicator: Improve the condition of protected nature sites.
135 In 2007/08 an updated UK BAP priority list was published containing 1150 species and 65 habitats across the UK, of which 606 species and 60 habitats are in Scotland.
136 Department of the Environment (1994). Biodiversity: the UK Action Plan. HMSO
Status of wild bird populations
137 The population of wintering water birds is measured in the winter beginning in the year indicated, i.e. 2013 indicates populations measured from approximately November 2013 - March 2014. Data displayed for wintering water birds is smoothed.
138 BTO Breeding Bird Survey.
139 JNCC Seabird Monitoring Programme.
140 Wetland Birds Survey.
Status of selected fish stocks
141 The data for the fish stocks are the current best estimates of each stock and not the historic estimates. The full time series is revised for each stock every time an assessment is re-run and although values at the most recent end of the time series may change markedly in some cases, most other values remain stable.
142 Figures for herring are for North Sea stocks, figures for haddock include North Sea, Skagerrak and West of Scotland, figures for cod include North Sea, Skagerrak and the eastern English channel and figures for saithe include North Sea & Skagerrak, West Coast of Scotland and Rockall.
143 The spawning stock biomass (SSB) is the total weight of mature fish (capable of spawning) in a particular stock.
144 The precautionary biological limit (Bpa) indicates the SSB below which the stock is considered to be at risk of suffering reduced reproductive capacity, indicating that spawning levels may be insufficient to guarantee stock replenishment and that stock abundance will probably decrease. The Bpa for each stock is defined by the International Council for the Exploration of the Sea ( ICES).
145 Figures for haddock have still to be approved by ICES and so are provisional until November 2016.
146 The Bpa for saithe was revised downwards from 200 kt to 150 kt this year, while the Bpa for haddock has been revised upwards from 88 kt to 132 kt.
Catches of Wild Salmon
147 Includes grilse (salmon which have matured, or are about to mature, after one winter at sea).
148 Fixed engine fisheries operate in coastal areas. Net & coble fisheries are generally restricted to estuaries and the lower reaches of rivers. Rod & line fisheries cover recreational angling within river systems.
149 Since 1994, numbers of fish reported as caught and released by anglers have been reported separately. Prior to this, only numbers caught and retained are available. No figures for fishing effort for rod & line catches are available.
150 Further information on Scottish salmon and sea trout stocks can be found in the Marine Scotland Science Report 01/15: Status of Scottish salmon and sea trout stocks 2014 report.