Authorisation of marine fish farms in Scottish waters: locational guidelines

Category 1, 2 and 3 areas designated on the basis of Marine Scotland Science (MSS) predictive models to estimate environmental sensitivity of sea lochs.

This document is part of a collection


The following tables and maps describe the Category 1, 2 and 3 areas for the Scottish Government Locational Guidelines, designated on the basis of MSS predictive modelling to estimate nutrient enhancement and benthic impact in sea lochs or similar water bodies supporting aquaculture.

For a detailed explanation of how these categorisations were derived, refer to the Scottish Fisheries Research Report ‘Scottish Government Locational Guidelines for fish farming: Predicted levels of nutrient enhancement and benthic impact’. Predictive models were used to assign each sea loch an index of ‘nutrient enhancement’ and ‘benthic impact’.

The sum of these indices was used for the categorisation of areas as indicated below.

Combined 'nutrient enhancement' and 'benthic impact' indices

Category

7 – 10 1
5 – 6 2
0 – 4 3

These tables and maps were last updated in December 2023. Maps are available on the Marine Scotland website. The next update will be March 2024.

Please note that the Sealoch parameters used in the MSS Locational Guidelines predictive models for the calculation of the sea loch categories can now be found at the end of this document.

Category 1 areas

For 'Maximum biomass (tonnes)', biomasss is as consented by SEPA at time of modelling, taking into consideration grouped and rotational sites.

For 'Total biomass (tonnes)', biomass is as consented by SEPA at the time of modelling on a site-by site-basis.

 

Loch

Maximum biomass (tonnes)†

Total biomass (tonnes)#

‘Nutrient enhancement’ index

‘Benthic impact’ index

‘Combined’ index

1

Loch Airdbhair (inc Loch na Droigniche)

 

375

 

375

 

3

 

4

 

7

2

Calbha Bay

1080

1080

4

3

7

3

Loch Meanervagh

433

433

4

4

8

4

Northra Voe

500

500

4

3

7

5

Sandsound Voe

5136

5136

4

3

7

6

Loch Sheilavaig

1211

2111

4

4

8

7

Stromness Voe

1650

1650

4

3

7

8

Vaila Sound

3595

3595

4

3

7

9

Vidlin Voe

2846

2846

4

3

7

10

Weisdale Voe

3952

3952

4

3

7

† Biomass as consented by SEPA at time of modelling, taking into consideration grouped and rotational sites.

# Biomass as consented by SEPA at the time of modelling on a site by site basis.

Category 2 areas

For 'Maximum biomass (tonnes)', biomasss is as consented by SEPA at time of modelling, taking into consideration grouped and rotational sites.

For 'Total biomass (tonnes)', biomass is as consented by SEPA at the time of modelling on a site-by site-basis.

 

Loch

Maximum biomass (tonnes)

Total biomass (tonnes)

‘Nutrient enhancement’ index

‘Benthic impact’ index

‘Combined’ index

1

A’Choire

1400

1400

3

3

6

2

Loch Ainort

1800

1800

2

3

5

3

Aith Voe

3484

3484

3

2

5

4

Loch A’Laip

750

750

3

3

 6

5

Badcall Bay

1007

1607

3

3

6

6

Baltasound

2185

2185

3

2

5

7

Basta Voe

4461

4461

3

3

6

8

Loch Boisdale

4071

4071

3

3

6

9

Brindister Voe / Vementry Sound

2166

2166

3

2

5

10

Busta Voe

1050

1050

3

2

5

11

Loch Carnan

410

410

3

3

6

12

Cat Firth

1343

1343

3

2

5

13

Loch Clash

540

540

2

3

5

14

Clift Sound

4982

4982

3

3

6

15

Dales Voe North

850

850

3

2

5

16

Dury Voe

5460

5460

3

2

5

17

East  Loch Tarbert

13212

13212

2

3

5

18

Loch Eport

1589

1589

2

3

5

19

Loch Erisort / Leurbost   

8777

8777

2

3

5

20

Loch Greshornish

2195

2195

2

3

5

21

Loch Grimshader

622

622

3

3

6

22

Loch Grosebay

2001

2001

3

3

6

23 

Gruting Voe

4395

4395

4

2

6

24

Loch Harport

2000

2000

2

3

5

25

Loch Kishorn

3500

4799

2

3

5

26

Loch Laxfirth   

942

942

3

2

5

27

Mid Yell Voe

1210

1210

3

3

6

28

Loch Nedd

250

250

2

3

5

29

Loch Odhairn

2801

2801

3

3

6

30

Olna Voe

2500

2500

3

3

6

31

Loch Pooltiel

2700

2700

3

2

5

32

Loch Portree

4214

4214

3

3

6

33

Ronas Voe

2350

2350

3

2

5

34

Loch Seaforth

7380

7380

2

3

5

35

Loch Shell

6453

6453

2

3

5

36

Loch Skiport

2460

2460

3

3

6

37

Swarbacks Minn

19842

20342

3

3

6

38

Swining Voe

1920

1920

3

2

5

39

Swinister Voe

13227

13227

3

3

6

40

Uig Bay

1625

1625

3

3

6

41

Loch Uiskevagh

1104

1104

3

3

6

42

Wadbister Voe

800

800

3

2

5

Category 3 areas

Loch

Maximum biomass (tonnes)†

Total biomass (tonnes)#

‘Nutrient enhancement’ index

‘Benthic impact’ index

‘Combined’ index

1

Loch Ailort

300

300

1

1

2

2

Loch Aline

0

0

0

0

0

3

Loch Alsh (inc Loch Long)

5600

5600

2

2

4

4

Loch Arnish

0

0

0

0

0

5

Loch Bay

500

500

1

1

2

6

Loch Bracadale

2075

2075

1

1

2

7

Broad Bay

2240

2240

1

1

2

8

Loch Broom

1050

1050

1

1

2

9

Burwick Bay

0

0

0

0

0

10

Loch Cairnbhain (inc. Loch Glendhu and Loch Glencoul)

3350

3350

2

2

4

11

Loch Caolisport

192

192

1

1

2

12

Loch Carron

2687

2687

1

2

3

13

Loch Claidh

0

0

0

0

0

14

Collafirth Voe

0

0

0

0

0

15

Loch Craignish

3183

3183

2

2

4

16

Loch Creran

3000

3000

2

2

4

17

Dales Voe

0

0

0

0

0

18

Loch Duich

2500

2500

2

2

4

19

Loch Dunvegan

5945

5945

2

2

4

20

Loch Eishort

1200

1200

2

2

4

21

Loch Eriboll

1395

1395

1

1

2

22

Loch Etive

4004

4004

2

2

4

23

Loch Ewe

1

1

1

0

1

24

Loch Eynort

20

20

1

1

2

25

Loch Feochan

0

0

0

0

0

26

Loch Fyne

13557

13557

1

2

3

27

Loch Geocrab

200

200

2

2

4

28

Loch Hourn

3625

3625

1

2

3

29

Loch Inchard

0

0

0

0

0

30

Loch Kilerivagh

0

0

0

0

0

31

Kirk Hope   

0

0

0

0

0

32

Loch Laxford

1390

2026

2

2

4

33

Loch Leven

1607

1607

2

2

4

34

Loch Linnhe (inc.Loch Eil)

5000

5000

1

2

3

35

Little Loch Broom

1997

1997

1

2

3

36

Loch Long (inc. Loch Goil)

4522

4522

1

1

2

37

Loch Melfort

615

615

1

1

2

38

Loch Mharabhig

0

0

0

0

0

39

Loch Moidart

0

0

0

0

0

40

Loch na Keal

2770

2770

1

2

3

41

Loch Nevis

4480

4480

1

2

3

42

Pierowall Bay

165

165

2

2

4

43

Loch Riddon

0

0

0

0

0

44

Loch Roag

15739

15739

2

2

4

45

Loch Ryan

0

0

0

0

0

46

Loch Scridain

1900

1900

1

1

2

47

Selivoe

963

963

3

1

4

48

Loch Slapin

350

350

1

2

3

49

Loch Sligachan

0

0

0

0

0

50

Loch Snizort Beag

500

500

1

2

3

51

Loch Spelve

1578

1578

2

1

3

52

Loch Stockinish

0

0

0

0

0

53

Loch Striven

4673

4673

2

2

4

54

Loch Sunart

5680

5680

1

2

3

55

Loch Sween

0

0

0

0

0

56

Tobermory Bay

0

0

0

0

0

57

Loch Torridon

7685

7685

1

2

3

58

Loch Tuath

2572

2572

1

2

3

59

West Burra Firth

0

0

0

0

0

60

West  Loch Tarbert

4658

4658

2

2

4

61

Whalefirth Voe

813

813

2

2

4

62

Whiteness Voe

500

500

3

1

4

† Biomass as consented by SEPA at time of modelling, taking into consideration grouped and rotational sites.

# Biomass as consented by SEPA at the time of modelling on a site by site basis

Prevous reports are in our website archive.

Sealoch parameters* used in the MSS Locational Guidelines predictive models

* The majority of these parameters have been taken from Edwards and Sharples (1986), however the volumes and areas were re-calculated in 2006 by digitising the depth contours on Admiralty charts.

Loch name

Length (km)

Area (km squared) Volume (mm cubed)) Tidal range (m) Tf (days)

(Mm cubed 3 year-1)

A’Choire

2.3

1.3

17.1

3.4

3.0

2077

Ailort

8.1

8.7

91.3

4.3

1.9

17542

Ainort

3.9

3.5

52.5

4.6

2.5

7665

Airdbhair

2.2

0.4

2.1

4.2

0.9

839

Aith Hope

1.8

0.6

3.0

2.3

1.7

644

AIith Voe

4.0

4.8

117.7

1.7

10.7

4015

A’Laip

2.5

1.1

5.7

3.9

1.0

2072

Aline

3.5

1.8

17.5

3.4

2.2

2903

Alsh

13.1

27.2

933.9

4.6

5.6

60873

Arnish

2.0

2.0

61.1

3.2

7.2

3097

Badcall Bay

1.9

1.3

13.9

3.6

2.3

2208

Baltasound

2.9

3.7

30.5

1.9

3.3

3375

Basta Voe

5.2

5.7

75.5

1.9

5.2

5298

Bay

6.9

15.4

343.0

4.5

3.7

33837

Boisdale

5.7

4.7

55.1

3.8

2.3

8749

Bracadale

10.5

45.8

1053.9

3.1

5.6

68693

Brindister

5.5

5.0

46.2

1.7

4.1

4112

Broad Bay

14.0

82.5

1357.7

4.1

3.0

165188

Broom

14.7

16.0

391.6

4.5

4.1

34864

Burswick

0.9

0.4

4.4

0.9

8.5

189

BUSTA

3.0

3.0

50.7

1.7

7.3

2537

Cairnbhain

14.9

14.0

330.6

4.2

4.2

28727

Calbha Bay

1.4

0.7

8.2

3.6

2.6

1153

Caolisport

8.3

14.9

163.4

0.9

9.1

6552

Carnan

1.8

0.7

2.1

3.9

0.6

1294

Carron

26.7

20.6

602.5

4.7

4.7

46791

Cat Firth

3.0

2.8

26.9

1.8

4.1

2395

Claidh

6.7

4.5

97.6

4.2

3.9

9134

Clash

1.6

1.0

17.2

4.2

3.0

2096

Clift Soundf

10.0

8.5

123.6

1.4

7.8

5782

Collafirth

2.4

0.9

11.5

1.8

5.1

820

Craignish

8.8

14.6

202.0

2.1

5.0

14750

Creran

12.8

12.4

161.1

3.3

3.0

19600

Dales Voe

4.9

3.2

47.3

1.2

9.2

1877

Dales Voe North

5.1

3.1

48.2

1.8

6.4

2751

Duich

8.3

11.2

510.7

4.6

7.4

25191

Dunvegan

10.4

21.7

1255.5

4.5

9.6

47736

Dury Voe

6.5

13.0

308.5

1.4

13.1

8597

East Loch Tarbert

8.5

26.2

518.5

4.2

3.6

52575

Eishort

5.2

2.5

19.4

4.3

1.4

5045

Eport

7.0

3.9

27.4

4.1

1.3

7695

Eriboll

15.5

37.5

954.1

4.3

4.4

79150

Erisort/Leurbost

14.6

15.8

227.0

4.1

2.6

31873

Etive

29.5

28.3

948.7

1.8

13.9

24913

Ewe

11.9

43.0

846.3

4.4

3.4

90853

Eynort

4.3

2.2

17.3

4.1

1.4

4502

Feochan

6.7

2.8

17.9

3.3

1.5

4356

Fyne

60.5

183.3

9440.2

3.1

12.4

277876

Geocrab

2.5

0.6

5.4

4.2

1.6

1227

Greshornish

5.9

4.7

74.1

4.6

2.6

10403

Grimshader

3.5

0.9

8.4

4.1

1.7

1806

Grosebay

2.6

2.9

47.9

4.2

2.9

6025

Gruting

7.6

6.7

95.7

1.1

9.7

3600

Harport

12.5

7.2

108.8

4.3

2.7

14710

Hourn

21.3

34.5

1905.0

4.2

9.8

70953

Inchard

6.6

3.7

77.1

4.2

3.7

7608

Kilerivach

4.2

1.0

2.2

3.9

0.5

1606

Kirk Hope

1.8

0.6

4.4

2.3

2.4

669

Kishorn

4.1

7.8

191.3

4.7

3.9

17901

Laxfirth

3.8

2.3

21.1

1.8

3.9

1977

Laxford

7.0

7.2

107.5

4.2

2.7

14528

Leven

13.4

8.1

149.2

3.7

3.8

14335

Linnhe

29.1

33.7

1303.7

3.7

7.8

61006

Little L Broom

12.7

23.0

914.7

4.5

6.6

50587

Long

26.9

44.0

1758.0

3.1

9.6

66840

Meanervach

1.4

0.2

0.8

3.9

0.9

315

Melfort

6.0

10.2

256.5

2.3

8.2

11418

Mharabhig

1.3

0.5

1.7

4.1

0.7

864

Mid Yell

3.3

1.7

11.7

1.9

2.7

1576

Moidart

2.8

2.9

8.6

4.3

0.6

5232

Na Keal

10.7

32.2

694.7

3.8

4.3

58966

Nedd

2.4

0.5

3.3

4.2

1.1

1110

Nevis

17.2

29.9

1505.0

4.3

8.8

62424

Northra Voe

1.0

0.3

2.2

1.5

4.2

187

Odhairn

3.6

1.8

29.8

4.1

3.1

3511

OlnaVoe

4.6

4.0

79.6

1.7

8.7

3341

Pierowall Harbour

1.6

1.1

3.5

2.3

1.0

1286

Pool Tiel

3.9

3.9

111.4

3.1

7.0

5808

Portree

4.9

4.1

88.3

4.6

3.5

9212

Riddon

5.3

2.8

49.8

2.6

5.1

3561

Roag

14.0

68.3

1135.5

3.6

3.5

118419

Ronas Voe

9.4

9.4

176.0

1.7

8.2

7834

Ryan

13.4

36.6

166.4

2.8

1.3

46720

Sandsound

8.6

6.0

69.7

1.1

7.9

3219

Scridain

12.0

27.0

734.2

3.7

5.5

48721

Seaforth

22.6

24.6

604.1

4.2

4.4

50111

Selivoe

4.0

4.8

88.9

1.1

12.5

2597

Sheilavaig

3.0

0.6

1.5

4.1

0.5

1105

Shell

7.5

15.0

391.5

4.1

4.8

29769

Skiport

4.6

3.0

38.9

4.1

2.4

5919

Slapin

3.4

2.1

11.6

4.3

1.0

4219

Sligachan

4.4

1.7

15.7

4.6

1.5

3809

Snizort Beg

4.7

6.9

101.9

4.6

2.5

14884

Spelve

7.7

8.9

144.9

3.5

3.5

15111

Stockinish

3.5

1.5

17.8

4.2

2.1

3093

Striven

12.9

14.3

546.7

2.6

11.0

18142

StromnessVoe

4.6

2.3

13.6

1.1

4.1

1209

Sunart

30.7

50.6

1754.0

4.0

6.5

98493

Swarbacks Minn

13.0

30.9

995.1

1.7

14.1

25759

Sween

14.8

17.4

216.9

1.6

5.9

13418

Swining Voe

4.0

3.5

63.1

1.8

7.6

3031

Swinster Voe

6.3

14.9

367.5

1.8

4.9

27377

Tobermory Bay

1.6

1.6

36.6

3.7

4.7

2842

Torridon

22.2

68.5

3300.2

4.9

7.4

162779

Tuath

9.5

23.4

412.4

3.5

3.8

39616

Uig Bay

8.8

3.1

64.8

3.1

5.1

4639

Uiskevagh

3.3

1.9

10.0

4.1

1.0

3652

Vaila Sound

3.5

3.6

35.6

1.2

6.1

2128

Vidlin Voe

3.0

2.7

37.3

1.8

5.7

2392

Wadbister Voe

2.1

1.6

18.2

1.8

4.7

1416

Weisdale

6.7

6.0

104.0

1.1

11.7

3244

West Burra Firth

1.6

0.9

10.4

1.3

6.7

567

West Loch Tarbert

6.5

23.2

396.9

3.8

3.4

42614

Whalefirth

6.3

3.1

28.0

1.9

3.6

2839

Whiteness Voe

4.5

3.0

36.0

1.1

8.3

1583

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