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Publication - Research and analysis

Report on razor clam surveys on Tarbert Bank

Published
30 November 2023
Directorate
Marine Directorate
Part of
Marine and fisheries
ISBN
9781835216330

This report describes a survey carried out on Tarbert Bank in 2023 to estimate the densities and sizes of razor clams, Ensis siliqua and Ensis magnus. The survey was conducted as part of the Scottish Government’s electrofishing scientific trial.

View supporting documents Supporting documents

Appendix 1: Summary details of tows on Tarbert Bank.

Date Tow Depth (m) UTC Start (h:min) Lat Mid-tow (deg) Lon Mid-tow (deg) Tow Duration (mins) Tow Length (m) Av Speed (m min-1) Average Exposure Time (s) Swath Width (m) Swept Area (m2) Count Whole siliqua Small (Cat 1) Count Whole siliqua Medium (Cat 1) Count Whole siliqua Large (Cat 1) Count Whole siliqua All Sizes (cat 1) Count Partial siliqua (Cat2) Count Tops (Cat3) Count Whole magnus (Cat4) Count Partial magnus (Cat5) Mean Dens siliqua Small (m-2) Mean Dens siliqua Medium (m-2) Mean Dens siliqua Large (m-2) Mean Dens siliqua All Sizes (m-2)
16/02 1 14.5 09:28 56.00511 -6.06592 14 48 3.5 35 1.0 50.5 2 12 22 36 5 7 0 0 0.050 0.300 0.551 0.901
16/02 2 15.0 09:52 56.00449 -6.06710 15 26 1.7 69 1.0 27.4 1 6 28 35 3 3 0 0 0.041 0.247 1.155 1.443
16/02 3 15.0 10:21 56.00364 -6.06795 14 23 1.7 72 1.0 24.5 1 6 6 13 5 3 0 0 0.058 0.349 0.349 0.756
16/02 4 15.0 10:49 56.00253 -6.06797 14 44 3.1 38 1.0 45.9 6 14 26 46 7 1 0 0 0.144 0.335 0.622 1.101
16/02 5 15.0 11:14 56.00160 -6.06741 12 46 3.8 31 1.0 47.8 2 5 18 25 2 0 0 0 0.043 0.109 0.391 0.544
16/02 6 15.0 11:37 56.00097 -6.06726 14 22 1.6 75 1.0 23.4 3 6 11 20 2 1 0 0 0.141 0.282 0.518 0.941
16/02 7 15.0 12:00 56.00034 -6.06805 14 25 1.8 68 1.0 25.8 0 5 19 24 5 1 0 0 0.000 0.222 0.844 1.066
16/02 8 15.0 12:22 55.99964 -6.06825 15 30 2.0 59 1.5 45.5 0 6 8 14 0 5 0 0 0.000 0.179 0.238 0.417
16/02 9 16.0 13:20 55.99454 -6.07162 15 30 2.0 59 1.5 45.5 1 7 15 23 3 6 1 0 0.029 0.202 0.434 0.665
16/02 10 16.0 13:41 55.99421 -6.07289 15 34 2.3 52 1.5 51.7 2 7 16 25 3 0 0 0 0.041 0.143 0.328 0.512
16/02 11 16.0 14:02 55.99385 -6.07456 15 30 2.0 60 1.5 44.8 2 7 11 20 0 3 0 0 0.051 0.180 0.282 0.513
16/02 12 16.0 14:25 55.99345 -6.07605 15 33 2.2 55 1.5 48.8 2 4 23 29 4 3 0 0 0.048 0.096 0.552 0.696
16/02 13 16.0 14:46 55.99309 -6.07737 15 35 2.3 52 1.5 51.9 1 10 17 28 6 2 1 0 0.023 0.227 0.385 0.635
16/02 14 16.0 15:07 55.99261 -6.07910 15 40 2.7 45 1.5 60.0 3 9 24 36 5 5 0 0 0.060 0.181 0.483 0.725
16/02 15 16.0 15:28 55.99220 -6.08061 15 38 2.5 48 1.5 56.6 2 16 34 52 2 7 3 0 0.041 0.324 0.689 1.054
25/02 16 14.0 09:47 56.00990 -6.05375 20 76 3.8 32 1.5 113.8 24 73 118 215 27 27 3 0 0.250 0.761 1.230 2.241
25/02 17 14.0 10:20 56.01184 -6.05282 13 59 4.6 26 1.5 89.0 8 56 108 172 14 19 3 0 0.103 0.723 1.394 2.221
25/02 18 14.0 10:48 56.01369 -6.05193 19 68 3.6 34 1.5 101.5 32 88 72 192 15 15 4 0 0.352 0.967 0.791 2.110
25/02 19 14.5 11:16 56.01558 -6.05075 22 88 4.0 30 1.5 132.4 58 116 108 282 21 20 3 0 0.485 0.970 0.903 2.359
25/02 20 16.0 12:26 56.00644 -6.07172 18 85 4.7 25 1.5 127.9 3 39 90 132 10 29 3 0 0.029 0.382 0.882 1.293
25/02 21 17.0 12:51 56.00820 -6.07141 15 71 4.7 25 1.5 106.3 9 38 53 100 8 9 2 0 0.096 0.403 0.563 1.061
25/02 22 18.0 13:14 56.00977 -6.07055 17 79 4.6 26 1.5 117.9 6 48 83 137 5 26 2 0 0.061 0.491 0.849 1.401
25/02 23 20.0 13:39 56.01109 -6.06929 17 72 4.2 28 1.5 108.3 5 14 26 45 5 7 1 0 0.056 0.156 0.290 0.502
25/02 24 19.0 14:40 55.99542 -6.09004 17 62 3.6 33 1.5 93.0 0 30 54 84 10 16 0 0 0.000 0.403 0.726 1.129
25/02 25 17.0 15:06 55.99513 -6.08728 18 62 3.4 35 1.5 92.5 2 16 97 115 9 15 1 0 0.025 0.202 1.225 1.452
25/02 26 16.0 15:32 55.99525 -6.08441 15 71 4.7 25 1.5 106.5 4 16 84 104 3 22 0 0 0.046 0.184 0.967 1.197
25/02 27 16.0 15:56 55.99524 -6.09799 20 74 3.7 32 1.5 111.2 1 21 101 123 12 16 1 0 0.011 0.222 1.069 1.302
26/02 28 19.0 09:24 55.98636 -6.08982 18 79 4.4 27 1.5 119.0 4 20 84 108 16 19 0 0 0.042 0.210 0.883 1.135
26/02 29 19.0 09:50 55.98772 -6.08837 18 73 4.0 30 1.5 109.0 4 15 94 113 9 18 2 0 0.044 0.165 1.032 1.240
26/02 30 18.0 10:16 55.98904 -6.08712 18 70 3.9 31 1.5 104.9 2 17 73 92 12 7 0 0 0.022 0.185 0.794 1.001
26/02 31 18.0 10:43 55.99059 -6.08617 17 74 4.4 27 1.5 111.4 3 14 44 61 5 13 1 0 0.034 0.157 0.494 0.685
26/02 32 16.5 11:48 55.99772 -6.06426 22 73 3.3 36 1.5 108.9 2 18 35 55 5 4 1 0 0.021 0.185 0.359 0.564
26/02 33 15.5 12:21 55.99920 -6.06298 18 78 4.4 28 1.5 117.5 0 14 51 65 9 10 0 0 0.000 0.146 0.531 0.677
26/02 34 15.0 12:51 56.00063 -6.06124 17 69 4.1 29 1.5 103.9 1 17 19 37 9 8 3 0 0.013 0.216 0.242 0.470
26/02 35 14.5 13:17 56.00189 -6.05944 19 68 3.6 33 1.5 102.3 6 29 38 73 8 9 1 0 0.069 0.334 0.437 0.840
26/02 36 14.0 13:44 56.00281 -6.05780 20 48 2.4 50 1.5 71.8 0 21 38 59 12 10 1 0 0.000 0.371 0.671 1.042
26/02 37 14.0 16:11 56.01211 -6.04659 25 67 2.7 45 1.5 99.9 5 35 48 88 5 8 0 0 0.056 0.392 0.538 0.986
26/02 38 13.0 16:45 56.01059 -6.04658 20 65 3.2 37 1.5 97.2 10 73 142 225 6 16 1 0 0.112 0.814 1.583 2.509
26/02 39 14.0 17:12 56.00904 -6.04619 16 57 3.6 33 1.5 86.2 15 96 105 216 5 10 3 0 0.184 1.178 1.288 2.650
26/02 40 15.5 17:34 56.00761 -6.04530 17 84 5.0 24 1.5 126.7 4 37 66 107 5 17 1 0 0.037 0.345 0.615 0.997
27/02 41 16.0 10:10 56.01203 -6.06230 21 79 3.8 32 1.5 119.0 10 56 96 162 11 12 0 0 0.093 0.521 0.894 1.508
27/02 42 15.5 10:37 56.01085 -6.05794 18 71 3.9 30 1.5 106.5 17 57 95 169 23 13 1 0 0.183 0.612 1.021 1.816
27/02 43 15.0 11:02 56.00966 -6.05621 19 53 2.8 43 1.5 79.2 4 32 74 110 17 9 10 0 0.058 0.465 1.076 1.600
27/02 44 15.0 11:29 56.00849 -6.05458 15 51 3.4 35 1.5 77.1 14 57 72 143 11 12 1 0 0.204 0.829 1.047 2.080
27/02 45 14.5 11:49 56.00734 -6.05308 17 73 4.3 28 1.5 109.6 11 50 117 178 13 23 8 0 0.116 0.529 1.239 1.885
27/02 46 16.5 12:45 56.00952 -6.06539 19 62 3.3 37 1.5 93.5 11 52 83 146 11 12 8 0 0.131 0.620 0.990 1.741
27/02 47 15.0 13:11 56.00833 -6.06303 17 68 4.0 30 1.5 101.4 5 37 56 98 7 12 5 0 0.057 0.421 0.636 1.114
27/02 48 14.5 13:35 56.00728 -6.06099 16 54 3.4 36 1.5 80.5 6 43 63 112 14 24 4 0 0.095 0.678 0.993 1.765
27/02 49 14.5 14:00 56.00593 -6.05851 19 63 3.3 36 1.5 94.9 2 31 77 110 8 17 4 0 0.025 0.387 0.962 1.374
27/02 50 18.0 14:52 55.99884 -6.08333 18 94 5.2 23 1.5 141.0 9 24 162 195 23 56 5 0 0.085 0.228 1.538 1.851
27/02 51 17.5 15:17 56.00032 -6.08139 22 87 4.0 30 1.5 130.6 7 32 122 161 8 18 11 0 0.061 0.277 1.055 1.393
27/02 52 16.5 15:46 56.00156 -6.07935 13 71 5.4 22 1.5 106.3 7 19 80 106 13 20 3 0 0.082 0.223 0.937 1.242
27/02 53 16.0 16:06 56.00240 -6.07635 18 72 4.0 30 1.5 107.9 3 20 110 133 11 23 7 0 0.034 0.223 1.229 1.486
28/02 54 16.0 09:10 56.01092 -6.04443 20 69 3.5 35 1.5 103.5 6 32 72 110 12 14 1 0 0.068 0.365 0.821 1.254
28/02 55 15.5 09:35 56.01249 -6.04434 18 61 3.4 35 1.5 91.6 10 37 38 85 5 7 1 0 0.121 0.449 0.461 1.031
28/02 56 14.0 10:00 56.01395 -6.04388 18 51 2.8 42 1.5 76.5 10 19 49 78 4 20 3 0 0.166 0.316 0.815 1.297
28/02 57 14.5 10:26 56.01531 -6.04290 17 67 3.9 31 1.5 100.2 30 67 62 159 9 16 6 0 0.337 0.753 0.696 1.786
28/02 58 15.5 10:49 56.01658 -6.04156 17 60 3.5 34 1.5 90.1 28 83 118 229 12 15 6 0 0.339 1.004 1.427 2.769
28/02 59 15.5 11:41 56.00908 -6.06135 20 77 3.9 31 1.5 116.0 19 75 69 163 16 15 3 0 0.187 0.736 0.678 1.600
28/02 60 14.5 12:07 56.01054 -6.06021 21 61 2.9 41 1.5 91.8 14 37 60 111 11 18 1 0 0.185 0.488 0.791 1.464
28/02 61 15.5 12:36 56.01211 -6.05872 20 77 3.9 31 1.5 115.7 20 80 65 165 14 16 3 0 0.197 0.786 0.639 1.622
28/02 62 15.0 13:04 56.01358 -6.05702 19 62 3.3 37 1.5 93.0 33 122 152 307 25 35 12 0 0.408 1.509 1.880 3.797
01/03 63 22.5 09:48 55.97500 -6.10529 18 53 2.9 41 1.5 79.1 1 0 0 1 0 1 3 0 0.016 0.000 0.000 0.016
01/03 64 22.5 10:30 55.97786 -6.10293 17 69 4.1 30 1.5 103.3 14 64 8 86 12 11 103 0 0.153 0.699 0.087 0.939
01/03 65 21.5 10:58 55.97932 -6.10082 18 65 3.6 33 1.5 97.1 4 49 56 109 13 12 28 0 0.047 0.579 0.661 1.287
01/03 66 18.5 11:53 55.97692 -6.09505 17 88 5.2 23 1.5 131.6 13 37 71 121 13 17 26 0 0.116 0.329 0.631 1.075
01/03 67 19.0 12:17 55.97844 -6.09414 17 76 4.5 27 1.5 114.0 2 24 60 86 6 20 17 0 0.022 0.259 0.647 0.927
01/03 68 18.5 12:41 55.97994 -6.09284 17 60 3.5 34 1.5 89.6 3 25 84 112 12 16 11 0 0.040 0.330 1.109 1.479
01/03 69 18.0 13:05 55.98127 -6.09117 19 80 4.2 29 1.5 119.9 7 25 87 119 17 11 12 0 0.067 0.241 0.838 1.146
01/03 70 22.0 13:58 55.98495 -6.09845 19 62 3.3 37 1.5 93.1 58 138 3 199 14 13 104 0 0.672 1.598 0.035 2.305
01/03 71 21.0 14:24 55.98621 -6.09663 19 65 3.4 35 1.5 97.0 4 30 171 205 28 28 12 0 0.049 0.370 2.111 2.531
01/03 72 21.0 14:50 55.98763 -6.09510 20 65 3.3 37 1.5 98.0 4 30 211 245 24 36 1 0 0.049 0.366 2.573 2.987
01/03 73 20.0 15:16 55.98916 -6.09453 19 76 4.0 30 1.5 113.3 4 34 197 235 27 37 9 0 0.043 0.363 2.103 2.509
02/03 74 15.0 09:07 55.99545 -6.06837 18 73 4.1 30 1.5 109.6 7 12 50 69 6 9 4 0 0.075 0.128 0.532 0.735
02/03 75 15.0 09:30 55.99389 -6.06926 15 72 4.8 25 1.5 107.5 3 4 21 28 4 8 2 0 0.037 0.050 0.261 0.348
02/03 76 15.0 09:50 55.99220 -6.06964 18 60 3.3 36 1.5 90.3 4 9 28 41 3 5 0 0 0.051 0.116 0.359 0.526
02/03 77 15.5 10:14 55.99044 -6.06907 17 87 5.1 24 1.5 130.2 3 16 34 53 5 11 1 0 0.029 0.154 0.327 0.509
02/03 78 17.5 10:37 55.98908 -6.06763 19 76 4.0 30 1.5 113.5 2 9 28 39 4 11 1 0 0.023 0.105 0.327 0.456
02/03 79 18.5 11:30 55.99482 -6.08872 18 81 4.5 27 1.5 122.0 2 31 201 234 31 38 3 0 0.020 0.312 2.021 2.353
02/03 80 18.0 11:54 55.99592 -6.08659 21 73 3.5 34 1.5 110.1 3 25 196 224 19 22 3 0 0.031 0.259 2.028 2.318
02/03 81 18.0 12:21 55.99688 -6.08447 15 65 4.3 28 1.5 97.4 4 17 140 161 14 19 2 0 0.048 0.202 1.667 1.917
02/03 82 17.5 12:42 55.99797 -6.08255 18 62 3.4 35 1.5 92.7 2 14 93 109 9 21 0 0 0.027 0.186 1.238 1.451
02/03 83 17.0 13:05 55.99896 -6.08099 10 34 3.4 36 1.5 50.6 2 4 40 46 4 10 0 0 0.050 0.100 0.997 1.147
02/03 84 15.0 13:48 56.00936 -6.05602 14 65 4.7 26 1.5 97.8 8 54 69 131 16 6 1 0 0.091 0.611 0.781 1.482
02/03 85 14.5 14:09 56.00834 -6.05366 17 69 4.1 30 1.5 103.5 9 56 86 151 21 15 3 0 0.101 0.631 0.970 1.703
02/03 86 14.5 14:32 56.00743 -6.05118 16 67 4.2 29 1.5 100.8 7 52 76 135 20 17 2 0 0.083 0.618 0.903 1.605
02/03 87 16.0 14:55 56.00659 -6.04854 16 75 4.7 25 1.5 113.0 2 61 64 127 12 16 1 0 0.021 0.633 0.664 1.317
03/03 88 21.0 09:26 56.01703 -6.06797 18 75 4.1 29 1.5 111.8 45 219 48 312 32 43 76 0 0.468 2.277 0.499 3.244
03/03 89 20.0 09:53 56.01768 -6.08206 10 42 4.2 29 1.5 62.6 83 214 24 321 0 0 0 0 1.327 3.420 0.384 5.130
03/03 90 19.0 10:31 56.02033 -6.05537 15 76 5.1 24 1.5 114.5 113 190 127 430 0 0 0 0 0.987 1.660 1.109 3.756
03/03 91 19.0 10:54 56.02139 -6.05292 17 81 4.7 25 1.5 120.8 80 149 135 364 0 0 0 0 0.662 1.233 1.118 3.013
03/03 92 18.0 11:43 56.01378 -6.02952 10 39 3.9 31 1.5 58.3 89 271 7 367 0 0 0 0 1.526 4.647 0.120 6.293
03/03 93 17.5 12:02 56.01511 -6.02709 11 42 3.8 31 1.5 62.9 150 266 4 420 0 0 0 0 2.386 4.230 0.064 6.680
03/03 94 20.0 12:46 56.02332 -6.04599 20 74 3.7 33 1.5 110.7 69 136 111 316 0 0 0 0 0.623 1.229 1.003 2.855
03/03 95 20.0 13:12 56.02442 -6.04444 16 78 4.9 25 1.5 116.5 30 28 40 98 0 0 0 0 0.257 0.240 0.343 0.841

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Email: mss.fisheries.advice@gov.scot

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