Crab and Lobster Fisheries in Scotland: Results of Stock Assessments 2009-2012: Scottish Marine and Freshwater Science Vol 7 No 9
This report presents summaries of historic and recent landings data and the results of
stock assessments for brown crab, velvet crab and lobster, based on data collected
between 2009 and 2012.
6. Tables
Table 1: Crab and lobster species landed in Scotland between 2009 and 2012. Landings information from the Fisheries Management Database.
| Landings (tonnes) |
||||
|---|---|---|---|---|
| 2009 |
2010 |
2011 |
2012 |
|
| Brown crab |
9465 |
10546 |
11832 |
10892 |
| Velvet crab |
2728 |
2474 |
2147 |
2032 |
| Deep-water crab |
11 |
6 |
8 |
5 |
| Northern stone crab |
6 |
3 |
1 |
2 |
| Green crab |
226 |
214 |
237 |
301 |
| European lobster |
1092 |
1100 |
1219 |
1132 |
| Spiny lobster |
4 |
6 |
5 |
13 |
| Squat lobsters |
2 |
1 |
1 |
1 |
Table 2: Minimum landing size ( MLS) regulations in Scotland for commercially important crab and lobster species ( CW - carapace width mm; CL carapace length mm).
| Species |
MLS (mm) |
Area |
Year measure introduced |
|---|---|---|---|
| Brown Crab |
140 ( CW) |
All areas except East coast South of 56° |
2000 |
| 130 ( CW) |
East coast South of 56° excluding Firth of Forth |
2000 |
|
| Lobster |
87 ( CL) |
All areas except Shetland |
1999 |
| 90 ( CL) |
Shetland |
2001 |
|
| Velvet Crab |
65 ( CW) |
All areas except Shetland |
1989 |
| 70 ( CW) |
Shetland |
2001 |
Table 3: MSS Market sampling statistics, number of animals measured, number of trips sampled and percentage of trips sampled for brown crab by assessment area, 2009-2012.
| Year |
Clyde |
East Coast |
Hebrides |
Mallaig |
North Coast |
Orkney |
Papa Bank |
Shetland |
South East |
South Minch |
Sule |
Ullapool |
|
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Animals measured |
2009 |
110 |
3870 |
2084 |
0 |
903 |
2582 |
1321 |
1104 |
3781 |
513 |
2384 |
0 |
| 2010 |
0 |
3259 |
3301 |
0 |
0 |
9306 |
3938 |
745 |
1997 |
1039 |
5847 |
159 |
|
| 2011 |
42 |
2573 |
4437 |
0 |
0 |
6518 |
4545 |
1935 |
1171 |
1236 |
1554 |
0 |
|
| 2012 |
245 |
7134 |
6370 |
0 |
1259 |
11432 |
747 |
3461 |
2695 |
1048 |
10673 |
193 |
|
| Trips sampled |
2009 |
2 |
25 |
12 |
0 |
2 |
18 |
1 |
9 |
28 |
4 |
3 |
0 |
| 2010 |
0 |
27 |
8 |
0 |
0 |
78 |
2 |
11 |
25 |
6 |
14 |
1 |
|
| 2011 |
1 |
27 |
10 |
0 |
0 |
47 |
3 |
16 |
22 |
6 |
3 |
0 |
|
| 2012 |
4 |
35 |
19 |
0 |
3 |
70 |
1 |
15 |
33 |
3 |
17 |
2 |
|
| Percentage of trips sampled (%) |
2009 |
0.9 |
0.9 |
0.8 |
0 |
1.1 |
0.8 |
0.8 |
1.2 |
1.8 |
0.2 |
1.4 |
0 |
| 2010 |
0 |
1.1 |
0.5 |
0 |
0 |
3.1 |
1.8 |
1.5 |
1.5 |
0.3 |
7.2 |
0.2 |
|
| 2011 |
0.5 |
1.0 |
0.8 |
0 |
0 |
2.0 |
2.6 |
2.3 |
1.1 |
0.3 |
1.6 |
0 |
|
| 2012 |
1.9 |
1.1 |
1.5 |
0 |
1.6 |
3.0 |
0.8 |
1.7 |
1.6 |
0.2 |
9.9 |
0.3 |
Table 4: MSS Market sampling statistics, number of animals measured, number of trips sampled and percentage of trips sampled for velvet crab by assessment area, 2009-2012.
| Year |
Clyde |
East Coast |
Hebrides |
Mallaig |
North Coast |
Orkney |
Papa Bank |
Shetland |
South East |
South Minch |
Sule |
Ullapool |
|
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Animals measured |
2009 |
1331 |
1297 |
1120 |
0 |
0 |
3812 |
0 |
0 |
121 |
1271 |
0 |
0 |
| 2010 |
353 |
1791 |
911 |
0 |
0 |
6265 |
285 |
3233 |
147 |
0 |
0 |
0 |
|
| 2011 |
2159 |
631 |
1687 |
0 |
0 |
9925 |
0 |
3972 |
0 |
132 |
0 |
0 |
|
| 2012 |
2532 |
4008 |
2788 |
0 |
0 |
7560 |
0 |
4152 |
307 |
819 |
0 |
0 |
|
| Trips sampled |
2009 |
5 |
6 |
6 |
0 |
0 |
18 |
0 |
0 |
1 |
7 |
0 |
0 |
| 2010 |
3 |
14 |
6 |
0 |
0 |
23 |
1 |
6 |
1 |
0 |
0 |
0 |
|
| 2011 |
9 |
7 |
12 |
0 |
0 |
41 |
0 |
10 |
0 |
1 |
0 |
0 |
|
| 2012 |
10 |
18 |
15 |
0 |
0 |
30 |
0 |
11 |
2 |
4 |
0 |
0 |
|
| Percentage of trips sampled (%) |
2009 |
2.4 |
0.2 |
0.5 |
0 |
0 |
0.6 |
0 |
0 |
0.1 |
0.3 |
0 |
0 |
| 2010 |
1.3 |
0.6 |
0.4 |
0 |
0 |
0.8 |
1.7 |
0.5 |
0.1 |
0 |
0 |
0 |
|
| 2011 |
3.9 |
0.3 |
1.1 |
0 |
0 |
1.6 |
0 |
0.9 |
0 |
0.1 |
0 |
0 |
|
| 2012 |
4.9 |
0.7 |
1.4 |
0 |
0 |
1.4 |
0 |
0.9 |
0.1 |
0.3 |
0 |
0 |
Table 5: MSS Market sampling statistics, number of animals measured, number of trips sampled and percentage of trips sampled for lobster by assessment area, 2009-2012.
| Year |
Clyde |
East Coast |
Hebrides |
Mallaig |
North Coast |
Orkney |
Papa Bank |
Shetland |
South East |
South Minch |
Sule |
Ullapool |
|
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Animals measured |
2009 |
302 |
476 |
763 |
0 |
0 |
552 |
0 |
0 |
779 |
297 |
0 |
0 |
| 2010 |
92 |
374 |
1833 |
0 |
0 |
1605 |
346 |
1019 |
916 |
151 |
43 |
0 |
|
| 2011 |
229 |
602 |
403 |
0 |
0 |
1187 |
256 |
2098 |
904 |
550 |
101 |
0 |
|
| 2012 |
269 |
1085 |
557 |
0 |
36 |
2078 |
208 |
707 |
1172 |
307 |
0 |
0 |
|
| Trips sampled |
2009 |
4 |
12 |
11 |
0 |
0 |
16 |
0 |
0 |
17 |
3 |
0 |
0 |
| 2010 |
4 |
12 |
18 |
0 |
0 |
25 |
2 |
8 |
19 |
2 |
1 |
0 |
|
| 2011 |
4 |
13 |
7 |
0 |
0 |
18 |
4 |
17 |
15 |
4 |
1 |
0 |
|
| 2012 |
6 |
16 |
3 |
0 |
1 |
33 |
1 |
15 |
21 |
5 |
0 |
0 |
|
| Percentage of trips sampled (%) |
2009 |
1.4 |
0.3 |
0.6 |
0 |
0 |
0.5 |
0 |
0 |
0.5 |
0.1 |
0 |
0 |
| 2010 |
1.1 |
0.4 |
1.0 |
0 |
0 |
0.8 |
1.7 |
0.9 |
0.6 |
0.1 |
1.1 |
0 |
|
| 2011 |
1.4 |
0.3 |
0.5 |
0 |
0 |
0.6 |
4.4 |
2.3 |
0.4 |
0.2 |
1.5 |
0 |
|
| 2012 |
2.1 |
0.4 |
0.2 |
0 |
0.6 |
1.3 |
1.1 |
1.8 |
0.6 |
0.3 |
0 |
0 |
Table 6: Biological parameters used in stock assessment for brown crab, velvet crab and lobster.
| Growth parameters |
Length-Weight relationship |
Terminal group |
Natural Mortality |
Source |
||||
|---|---|---|---|---|---|---|---|---|
| K |
L ∞ |
a |
b |
F |
M |
|||
| Brown crab |
||||||||
| Males |
0.197 |
220 |
0.000059 |
3.214 |
0.5 |
0.1 |
Chapman, 1994 |
|
| Females |
0.172 |
220 |
0.000302 |
2.8534 |
0.5 |
0.1 |
Chapman, 1994 |
|
| Shetland |
Males |
0.188 |
246 |
0.00008 |
3.166 |
0.406 |
0.242 |
Tallack, 2002 |
| Shetland |
Females |
0.224 |
227 |
0.00024 |
2.895 |
0.174 |
0.256 |
Tallack, 2002 |
| Velvet crab |
||||||||
| Males |
0.105 |
103 |
0.0003 |
3.0389 |
1.9 |
0.1 |
Chapman, 1994 |
|
| Females |
0.118 |
100 |
0.0009 |
2.7405 |
1.1 |
0.1 |
Chapman, 1994 |
|
| Shetland |
Males |
0.463 |
107 |
0.0011 |
2.75 |
0.31 |
0.576 |
Tallack, 2002 |
| Shetland |
Females |
0.463 |
100.1 |
0.0038 |
2.42 |
0.202 |
0.576 |
Tallack, 2002 |
| Lobster |
||||||||
| Males |
0.11 |
173.4 |
0.000126 |
3.36 |
0.5 |
0.1 |
Chapman, 1994 |
|
| Females |
0.13 |
150 |
0.000919 |
2.922 |
0.5 |
0.1 |
Chapman, 1994 |
|
| Shetland |
Males |
0.112 |
188 |
0.0017 |
2.797 |
0.316 |
0.1 |
Mouat et al., 2006 |
| Shetland |
Females |
0.136 |
184 |
0.0004 |
3.123 |
0.452 |
0.1 |
Mouat et al., 2006 |
Table 7: Percentage of total landings into Scotland of brown crab 2009-2012, by assessment area. Data are from the Fisheries Management Database.
| Species |
Year |
Clyde |
East Coast |
Hebrides |
Mallaig |
North Coast |
Orkney |
Papa Bank |
Shetland |
South East |
South Minch |
Sule |
Ullapool |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Brown crab (%) |
2009 |
1.1 |
8.4 |
19.5 |
0.1 |
6.1 |
12.4 |
10.8 |
4.2 |
3.3 |
10.8 |
21.2 |
2.1 |
| 2010 |
1.3 |
9.7 |
17.8 |
0.1 |
6.4 |
13.8 |
8.3 |
3.2 |
3.3 |
15.6 |
18.2 |
2.3 |
|
| 2011 |
1.2 |
9.4 |
20.7 |
0.2 |
3.7 |
15 |
7.6 |
3.6 |
3.1 |
14.0 |
19.4 |
2.1 |
|
| 2012 |
1.7 |
11.2 |
18.4 |
0.6 |
4.8 |
15.7 |
7.7 |
4.4 |
4.1 |
10.1 |
14.9 |
6.4 |
Table 8: Percentage of total landings into Scotland of velvet crab 2009-2012, by assessment area. Data are from the Fisheries Management Database.
| Species |
Year |
Clyde |
East Coast |
Hebrides |
Mallaig |
North Coast |
Orkney |
Papa Bank |
Shetland |
South East |
South Minch |
Sule |
Ullapool |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Velvet crab (%) |
2009 |
5.5 |
9.6 |
10.3 |
0.8 |
0.1 |
36.2 |
0.2 |
12.7 |
6.7 |
17.0 |
0 |
0.9 |
| 2010 |
5.5 |
9.1 |
12.7 |
1.1 |
0.2 |
35.4 |
1.2 |
10.5 |
3.6 |
18.8 |
0.1 |
1.8 |
|
| 2011 |
6.3 |
12.7 |
13.1 |
1.5 |
0.2 |
31.8 |
0.5 |
12.1 |
6.4 |
14.4 |
0 |
1.0 |
|
| 2012 |
5.7 |
15.2 |
15 |
2.6 |
0.3 |
24.2 |
0.3 |
11.7 |
6.6 |
16.2 |
0 |
2.2 |
Table 9: Percentage of total landings into Scotland of lobster 2009-2012, by assessment area. Data are from the Fisheries Management Database.
| Species |
Year |
Clyde |
East Coast |
Hebrides |
Mallaig |
North Coast |
Orkney |
Papa Bank |
Shetland |
South East |
South Minch |
Sule |
Ullapool |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Lobster (%) |
2009 |
1.9 |
18.1 |
15.7 |
0 |
1.3 |
17.8 |
1.1 |
2.8 |
28.5 |
11.0 |
0.4 |
1.4 |
| 2010 |
2.4 |
20.2 |
15.2 |
0.1 |
1.4 |
16.6 |
1.0 |
2.9 |
27.2 |
10.9 |
0.3 |
1.8 |
|
| 2011 |
2.3 |
24.2 |
12.3 |
0.1 |
1.3 |
15.4 |
0.6 |
2.5 |
32.3 |
7.8 |
0.3 |
0.9 |
|
| 2012 |
2.3 |
24.5 |
12.8 |
1.2 |
0.9 |
14.4 |
0.5 |
3.4 |
30.9 |
7.8 |
0.2 |
1.1 |
Table 10: Brown crab fishing mortality (F bar) from Length Cohort Analysis (2009-2012) in relation to F MSY. Fishing mortality calculated across a fixed range of 145-190 mm CW interval (150-200 mm for Shetland).
| Assessment area |
F bar |
F MSY | F MSY basis |
||
|---|---|---|---|---|---|
| Males |
Females |
Males |
Females |
||
| Clyde |
- |
- |
- |
- |
- |
| East Coast |
0.63 |
0.45 |
0.37 |
0.3 |
LCA 2006-2008 |
| Hebrides |
0.36 |
0.48 |
0.41 |
0.35 |
LCA 2006-2008 |
| Mallaig |
- |
- |
- |
- |
- |
| North Coast |
0.22 |
0.3 |
0.39 |
0.43 |
LCA 2006-2008 |
| Orkney |
0.64 |
0.41 |
0.33 |
0.36 |
LCA 2006-2008 |
| Papa Bank |
0.29 |
0.3 |
0.36 |
0.39 |
LCA 2009-2012 |
| Shetland |
0.77 |
0.49 |
0.83 |
1.47 |
LCA 2009-2012 |
| South East |
0.77 |
0.57 |
0.39 |
0.28 |
LCA 2006-2008 |
| South Minch |
0.48 |
0.47 |
0.34 |
0.25 |
LCA 2006-2008 |
| Sule |
0.39 |
0.42 |
0.36 |
0.36 |
LCA 2006-2008 |
| Ullapool |
- |
- |
- |
- |
- |
Table 11: Velvet crab fishing mortality (F bar) from Length Cohort Analysis (2009-2012) in relation to F MSY. Fishing mortality calculated across a fixed range of 60-80 mm interval (75-85 mm for Shetland).
| Assessment area |
F bar |
F MSY | F MSY basis |
||
|---|---|---|---|---|---|
| Males |
Females |
Males |
Females |
||
| Clyde |
0.54 |
0.59 |
0.15 |
0.39 |
LCA 2006-2008 |
| East Coast |
0.33 |
0.33 |
0.15 |
0.21 |
LCA 2006-2008 |
| Hebrides |
0.17 |
0.27 |
0.2 |
0.23 |
LCA 2006-2008 |
| Mallaig |
- |
- |
- |
- |
- |
| North Coast |
- |
- |
- |
- |
- |
| Orkney |
0.2 |
0.37 |
0.08 |
0.17 |
LCA 2006-2008 |
| Papa Bank |
- |
- |
- |
- |
- |
| Shetland |
2.73 |
2.88 |
3.81 |
4.26 |
LCA 2009-2012 |
| South East |
- |
- |
- |
- |
- |
| South Minch |
0.3 |
0.36 |
0.26 |
0.43 |
LCA 2006-2008 |
| Sule |
- |
- |
- |
- |
- |
| Ullapool |
- |
- |
- |
- |
- |
Table 12: Lobster fishing mortality (F bar) from Length Cohort Analysis (2009-2012) in relation to F MSY. Fishing mortality calculated across a fixed range of 95-130 mm interval (110-155 mm for Shetland).
| Assessment area |
F bar |
F MSY |
F MSY basis |
||
|---|---|---|---|---|---|
| Males |
Females |
Males |
Females |
||
| Clyde |
0.84 |
0.45 |
0.26 |
0.28 |
LCA 2006-2008 |
| East Coast |
0.36 |
0.48 |
0.26 |
0.32 |
LCA 2006-2008 |
| Hebrides |
0.38 |
0.29 |
0.18 |
0.34 |
LCA 2006-2008 |
| Mallaig |
- |
- |
- |
- |
- |
| North Coast |
- |
- |
- |
- |
- |
| Orkney |
0.48 |
0.33 |
0.23 |
0.32 |
LCA 2006-2008 |
| Papa Bank |
0.35 |
0.19 |
0.21 |
0.31 |
LCA 2009-2012 |
| Shetland |
0.19 |
0.33 |
0.24 |
0.16 |
LCA 2009-2012 |
| South East |
0.76 |
0.73 |
0.35 |
0.36 |
LCA 2006-2008 |
| South Minch |
0.86 |
0.83 |
0.36 |
0.41 |
LCA 2009-2012 |
| Sule |
- |
- |
- |
- |
- |
| Ullapool |
- |
- |
- |
- |
- |
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