Commercial fishing
An experimental fishery for sea cucumber started in Breiðafjörður in 2003, but little was landed until 2008 when fisheries started in Faxaflói (area E, Figure 1) with a catch of around 800 t.
Through the years 2008-2023, annual catches of sea cucumber have fluctuated. The annual catch in Faxaflói (E) ranged from 140-1175 t, off the east coast (areas F & G) from 136 to 2103 t and 0-559 t in Aðalvík (A). There was an increase in the catches during 2016-2019, but a considerable drop in catches in 2020 and 2021. Maximum landings were 5985 t in 2018; almost twofold increase from 2017, but catches declined to 5606 t in 2019 and to 1098 t in 2020. The low landings in 2020 can partly be explained by the fact that TAC of the 2019/2020 fishing year was almost fully reached during the autumn of 2019 and slower start of the autumn fishery in 2020. According to stakeholders, the slow start was because of a mutual agreement to even out the fishing effort over the full fishing year of 2020/2021. Difficult markets due to the COVID-19 pandemic could also explain the decreased effort. The majority of the 1429 t landed in 2021 were fished during the summer. Catches increased considerably in 2022 to 2822 t and in 2023 the catch was around 2401 t, most in area G with just over 1000 t (Figure 2 and Table 1).
| Year | A | B | C | D | DI. | E | F | G | H | Others | Total |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2008 | 2 | 210 | 0 | 8 | 0 | 832 | 0 | 0 | 0 | 0 | 1052 |
| 2009 | 559 | 25 | 0 | 0 | 0 | 448 | 136 | 0 | 0 | 0 | 1168 |
| 2010 | 167 | 0.5 | 27 | 0 | 54 | 1 135 | 286 | 577 | 0 | 0 | 2247 |
| 2011 | 0 | 0 | 0 | 0 | 0 | 910 | 231 | 1 514 | 0 | 0 | 2655 |
| 2012 | 0 | 0 | 0 | 0 | 0 | 753 | 39 | 622 | 0 | 0 | 1414 |
| 2013 | 0 | 0 | 0 | 0 | 285 | 493 | 10 | 636 | 0 | 0 | 1424 |
| 2014 | 0 | 0 | 0 | 0 | 2 | 687 | 22 | 137 | 0.6 | 0 | 848.6 |
| 2015 | 163 | 0 | 0 | 0 | 0 | 435 | 15 | 797 | 0 | 0 | 1410 |
| 2016 | 146 | 9 | 15 | 0 | 0 | 989 | 316 | 1 760 | 0 | 0 | 3265 |
| 2017 | 242 | 0.7 | 0.3 | 0 | 70 | 805 | 408 | 1 695 | 1.4 | 0 | 3222 |
| 2018 | 341 | 627 | 0.4 | 292 | 496 | 525 | 534 | 975 | 2195 | 0 | 5985 |
| 2019 | 496 | 1083 | 23 | 164 | 0 | 1 175 | 354 | 1 121 | 1024 | 165 | 5606 |
| 2020 | 63 | 74 | 66 | 39 | 0 | 302 | 184 | 645 | 43 | 49 | 1193 |
| 2021 | 64 | 58 | 30 | 39 | 0 | 143 | 78 | 784 | 226 | 7 | 1429 |
| 2022 | 115 | 145 | 28 | 25 | 0 | 337 | 326 | 1 535 | 312 | 0 | 2822 |
| 2023 | 176 | 112 | 23 | 54 | 0 | 259 | 412 | 1 081 | 284 | 0 | 2401 |
In 2023, landings from the Westfjord areas were 176 t from Aðalvík (area A), 112 t from area B and 23 t from area C. Landings from area D in outer Breiðafjörður were 54 t and 259 t from Faxaflói (area E). In eastern Iceland, 412 t was fished from the northern area (F), 1081 t from the middle area (G) and 284 t from the southern area (H).
In August of 2019, a new regulation was implemented, and fishing was only allowed in the eight demarcated areas (A-H), experimental license was mandatory for fishing activity outside of those. Within the experimental framework, limited fishing took place in July in northwestern Húnaflói (east of area A) with no landed catch. In August 2021 and March-May 2024, 7 and 29 t, respectively, were fished north of area F.
No fishing is permitted in May and June in the western areas (A-E) and in June and July in other areas due to spawning of sea cucumber. Sea cucumbers are fished by a dredge, 250 cm in width and with minimum mesh size of 80 mm. There is a lack of registration if one or two dredges have been used, but in recent years most of the boats have operated with two dredges (in calculations the effort of those boats was raised by the factor of 1.8).
There has been an overall declining trend in the raw catch per unit effort (CPUE) throughout the history of the sea cucumber fisheries, although a small increase was detected in 2021 on all grounds (Figure 3). Due to technical constraints more than half of the logbook data from 2022 are unavailable.
Surveys
Older surveys
From 2008-2010 several surveys were carried out on commercial fishing boats in Aðalvík (A) and Faxaflói (E). Based on 100% gear efficiency biomass was estimated to be 0.3 kg/m2 in Aðalvík (A) in 2008. In Faxaflói (E) during 2008, biomass was estimated to be 0.13 kg/m2 at Vestrahraun and 0.18 kg/m2 at Syðrahraun sub-locations.
In September 2017, a five days drop-frame camera survey was conducted in area G off the east coast of Iceland. In total 55 stations (ten images per station) on two grounds in southern part of the area. The densities of sea cucumbers were 0.6 and 0.7 individuals/m2, respectively. The mean whole wet weight (from fish processing) of sea cucumber from this area during the autumn of 2017 was 198 g, that yields a biomass of 0.119 and 0.139 kg/m2, respectively (mean 0.13 kg/m2).
Surveys in 2020-2024
Sea cucumber areas A, B, E, F, G and H were surveyed during a beam trawl survey in autumn 2020. The gear used was a 4 m wide beam trawl, lined with a 40 mm mesh size in the cod end. The beam trawl was towed between 0.5 to 1.2 nautical miles at each station (µ = 0.89) at a speed of 4 nm/h. Start position of each tow and towing direction were randomly generated. Overlapping tows and tows that ended outside known fishing areas based on VMS data were excluded. The second survey was carried out in 2021 and tows from 2020 repeated, one tow was added in area A and two tows were skipped in area E due to a difficult hard bottom. Three tows in area D were added in the survey of 2022.
Average density per nautical mile was from 699 on area H in 2023 to 2346 animals in area D in 2022. In general, small changes were observed within areas between years. Average gutted catch per nm was between 150 kg in area E in 2023 and highest 348 kg in area H in 2021 ( Table 2 & Figure 7). Biomass estimates for each area were based spatial modelling of the average gutted weight and size of know fishing areas (GLMMS model of the sdmTMB R package; Anderson et al., 2022). The lowest biomass estimate was in area B, or 798 t in 2024, but highest 7086 t in area G in 2024 (Figure 3). Recently, the biomass has been decreasing in the eastern areas (Table 2 & Figure 4 - 6).
| Year | No. tows | Count | Catch g. | Biom. index | L. conf.int | U. conf.int | |
|---|---|---|---|---|---|---|---|
| A | 2020 | 3 | 1 229 | 278 | 1 356 268 | 793 745 | 2 317 448 |
| 2021 | 4 | 1 040 | 257 | 1 448 458 | 951 023 | 2 206 078 | |
| 2022 | 4 | 1 095 | 237 | 1 292 494 | 823 872 | 2 027 672 | |
| 2023 | 4 | 1 273 | 233 | 1 538 780 | 1 005 425 | 2 355 068 | |
| 2024 | 4 | 763 | 223 | 928 119 | 585 512 | 1 471 199 | |
| B | 2020 | 4 | 1 130 | 232 | 1 063 190 | 697 678 | 1 620 194 |
| 2021 | 4 | 1 757 | 391 | 1 759 264 | 1 154 239 | 2 681 427 | |
| 2022 | 4 | 1 120 | 216 | 974 101 | 648 487 | 1 463 208 | |
| 2023 | 4 | 1 169 | 198 | 997 517 | 602 127 | 1 652 543 | |
| 2024 | 4 | 906 | 196 | 797 622 | 514 953 | 1 235 455 | |
| D | 2022 | 3 | 2 346 | 304 | |||
| E | 2020 | 14 | 1 226 | 179 | 3 745 936 | 2 929 612 | 4 789 726 |
| 2021 | 12 | 1 274 | 188 | 4 192 108 | 3 234 917 | 5 432 525 | |
| 2022 | 10 | 1 384 | 190 | 4 239 621 | 3 148 504 | 5 708 865 | |
| 2023 | 14 | 1 261 | 150 | 4 112 384 | 3 332 233 | 5 075 186 | |
| 2024 | 14 | 1 659 | 162 | 5 275 905 | 4 275 896 | 6 509 788 | |
| F | 2020 | 10 | 1 226 | 253 | 2 881 166 | 2 298 515 | 3 611 515 |
| 2021 | 10 | 1 202 | 275 | 2 783 983 | 2 221 466 | 3 488 941 | |
| 2022 | 10 | 1 077 | 228 | 2 736 386 | 2 153 998 | 3 476 238 | |
| 2023 | 9 | 873 | 202 | 2 030 791 | 1 609 308 | 2 562 662 | |
| 2024 | 10 | 1 023 | 208 | 2 390 240 | 1 953 797 | 2 924 176 | |
| G | 2020 | 14 | 1 713 | 347 | 6 389 178 | 5 585 175 | 7 308 920 |
| 2021 | 14 | 1 539 | 348 | 6 745 528 | 5 830 462 | 7 804 210 | |
| 2022 | 14 | 1 424 | 317 | 6 871 933 | 6 054 726 | 7 799 438 | |
| 2023 | 14 | 943 | 217 | 4 954 444 | 4 217 350 | 5 820 365 | |
| 2024 | 14 | 1 211 | 235 | 7 085 749 | 6 098 405 | 8 232 946 | |
| H | 2020 | 7 | 906 | 187 | 1 722 173 | 1 183 811 | 2 505 364 |
| 2021 | 7 | 1 094 | 230 | 2 123 064 | 1 513 444 | 2 978 241 | |
| 2022 | 7 | 931 | 196 | 1 808 601 | 1 254 266 | 2 607 929 | |
| 2023 | 7 | 699 | 213 | 1 658 990 | 1 124 543 | 2 447 436 | |
| 2024 | 7 | 882 | 229 | 2 335 327 | 1 677 535 | 3 251 053 |
It can be difficult to properly measure the length of the sea cucumbers, as the animal often contracts itself and becomes round shaped. To estimate changes is size frequency, both length and circumference was used, and the new length called “adjusted length”. The surface area of the animals was calculated as a cylinder, but without the top and the bottom area (as they are contracted at the ends), and the square root of that number calculated \(L_a = \sqrt{2*\pi*r*L}\). Length–weight relationship of the new adjusted length was stronger compared to using length or circumference (Figure 7).
In general sea cucumbers are heavier in eastern Iceland (Areas F-H) compared to areas in western Iceland (Areas A, B & E). The average adjusted length was also larger in the east and in general the cucumbers had thinner walls and were full of water (Figure 7 and Table 3).
| Year | Length (cm) | Circumference (cm) | Adj. length (cm) | Weight (g) | Drained weight (g) | |
|---|---|---|---|---|---|---|
| A | 2020 | 12.5 | 24.7 | 17.6 | 439.8 | 234.4 |
| 2021 | 13.4 | 25.9 | 18.6 | 497.8 | 241.4 | |
| 2022 | 14.2 | 25.2 | 18.9 | 486.9 | 212.0 | |
| 2023 | 14.5 | 27.4 | 19.9 | 595.2 | 232.7 | |
| 2024 | 13.3 | 24.8 | 18.1 | 453.8 | 223.2 | |
| B | 2020 | 12.0 | 22.5 | 16.4 | 366.4 | 207.1 |
| 2021 | 14.0 | 26.4 | 19.1 | 443.5 | 225.1 | |
| 2022 | 12.5 | 26.0 | 18.0 | 459.4 | 194.2 | |
| 2023 | 12.9 | 23.8 | 17.6 | 409.0 | 198.1 | |
| 2024 | 14.0 | 23.3 | 18.1 | 419.6 | 195.7 | |
| D | 2022 | 10.3 | 24.1 | 15.7 | 343.6 | 136.8 |
| E | 2020 | 11.9 | 20.4 | 15.6 | 291.7 | 156.3 |
| 2021 | 11.5 | 21.4 | 15.7 | 311.5 | 159.2 | |
| 2022 | 11.2 | 21.3 | 15.4 | 292.0 | 151.6 | |
| 2023 | 11.5 | 21.1 | 15.6 | 297.1 | 149.6 | |
| 2024 | 11.3 | 23.2 | 16.2 | 335.8 | 162.2 | |
| F | 2020 | 14.7 | 28.1 | 20.4 | 654.6 | 290.2 |
| 2021 | 13.9 | 28.3 | 19.8 | 629.2 | 225.7 | |
| 2022 | 14.1 | 28.7 | 20.1 | 658.4 | 212.5 | |
| 2023 | 13.6 | 25.6 | 18.7 | 505.1 | 201.8 | |
| 2024 | 14.3 | 28.2 | 20.1 | 617.5 | 208.3 | |
| G | 2020 | 14.1 | 28.5 | 20.1 | 664.7 | 290.6 |
| 2021 | 14.7 | 27.5 | 20.1 | 643.9 | 226.5 | |
| 2022 | 14.3 | 29.9 | 20.6 | 709.3 | 224.0 | |
| 2023 | 13.6 | 26.8 | 19.1 | 553.1 | 217.0 | |
| 2024 | 14.5 | 29.3 | 20.6 | 691.7 | 235.4 | |
| H | 2020 | 14.1 | 27.4 | 19.6 | 609.4 | 258.7 |
| 2021 | 14.1 | 26.9 | 19.5 | 628.5 | 215.6 | |
| 2022 | 14.5 | 29.8 | 20.8 | 764.7 | 220.0 | |
| 2023 | 13.4 | 28.6 | 19.6 | 645.8 | 213.4 | |
| 2024 | 14.1 | 27.8 | 19.8 | 636.4 | 228.9 |
Management
The Ministry of Food, Agriculture and Fisheries is responsible for management of the Icelandic fisheries and implementation of legislation. The sea cucumber stocks were included in the ITQ system in 2022, but prior to that when the issued TAC had been reached the area was closed with a regulation issued by the Ministry.
In 2009 three fishing zones were demarcated by the Ministry: 1) Western area: Reykjanes to Skagatá, 2) Northern area: Skagatá to Glettinganes and 3) Southern and eastern area: Glettinganes to Reykjanes. For each of these zones three fishing licenses were issued and it was not allowed to move from one zone to another. However, no fishing was conducted in the Northern area as limited fishing trials did not give positive results. In 2013, the Ministry abolished the area restriction. Initially, the main fishing areas were in Faxaflói and Aðalvík in the Western area, and since 2009 also off the east coast belonging to the Southern and eastern area. In 2013, the main fishing areas were defined by coordinates (Regulation 795/2013, Figure 1).
In 2009, the stock status in Faxaflói and Aðalvík were estimated, the fishing areas defined, and total allowable catch (TAC) advice issued for the first time. In 2012, the stock status off the east coast was estimated, which resulted in advice for demarcated area during the fishing year 2013/2014. Total TAC was given for the eastern area even though it was divided into two areas, until 2018/2019 when the TAC was divided (area F and G). When the maximum allowable catch had been reached within an area, the area was closed, but further fishing could be continued outside the defined areas.
In a letter in February 2019, the Ministry of Industries and Innovation requested a advice on fishing opportunities for sea cucumber by increasing number of sea cucumber management areas built on fishing ventures outside the previously managed areas (A, E, F & G). The new (mostly adjacent) areas were granted, and the management areas are now eight (A-H) (Anon, 2019).
Stock assessment
The catch advice for the quota year of 2024/2025 follows the ICES framework for stocks where analytical stock assessment can’t be implemented but biomass indices and information on life history are available (Areas A, B, E-H). The advice follows the \(rfb\) rule of ICES:
\[ A_{y+1} = A_{y-1} r f b m \]
where \(A_{y+1}\) is recommended catch, \(A_{y-1}\) is the recommendation of the previous year, \(r\) is the biomass ratio of the last two years (Index A) vs. the three previous years (Index B):
\[ r = \frac{\frac {\sum_{i_y-2}^{y-1}I_1} {2}} {\frac{\sum_{i=y-3}^{y-5}}{3}} \]
This year, the ratio of the last two years survey biomass index compared to the previous three years was used.
𝑓 is a fishing proxy for the exploitation (mean catch length divided by an MSY reference length):
\[ f=\frac{\bar{L}_{y-1}} {L_{F=M}} \]
where \(\bar{L}\) is the mean catch length above \(L_c\) (the length where frequency is half that of the modal value, see Figure 8). For the sea cucumber, adjusted length from the surveys was used (Figure 9).
\(L_{F=M}\) is calculated as:
\[ L_{F=M} = 0,75L_c + 0,25L_\infty \]
where \(L_\infty\) is the length where the frequency is half that of the modal value, and \(L_\infty\) is von Bertalanffy \(L_\infty\).
\(b\) is the biomass safeguard and is used to reduce catch advice when index falls below trigger, but that value has not yet been defined for the sea cucumber stocks.
\(m\) is a multiplier based on stock growth. For slow growing species like the sea cucumber (Hamel & Mercier, 1996), m = 0.95, but for fast growing species, m = 0.9. In general, advice according to the \(rfb\) rule is applied for two years (ICES, 2023), but due to the short biomass time series and lowering biomass in the eastern areas, the advice is currently given for one year.
Catch advice for each area is given in advice sheets but a summary table for previous years is found below in Table 4 .
References
Anon, 2019. MFRI Assessment Reports 2019. Sea cucumber – New areas. Marine and Freshwater Research Institute, 22 March 2019.
Anderson, S.C., E.J. Ward, P.A. English, L.A.K. Barnett. 2022. sdmTMB: an R package for fast, flexible, and user-friendly generalized linear mixed effects models with spatial and spatiotemporal random fields. bioRxiv 2022.03.24.485545.
Hamel, J.-F., & Mercier, A. (1996a). Early development, settlement, growth and spatial distribution of the sea cucumber Cucumaria frondosa (Echinodermata: Holothuroidea). Canadian Journal of Fisheries and Aquatic Sciences, 53, 253–271.
ICES. 2012. Implementation of Advice for Data-limited Stocks in 2012 in its 2012 Advice. ICES CM 2012/ACOM 68. http://www.ices.dk/sites/pub/Publication%20Reports/Expert%20Group%20Report/acom/2012/ADHOC/DLS%20Guidance%20Report 2012.pdf
ICES. 2021. Tenth Workshop on the Development of Quantitative Assessment Methodologies based on LIFE-history traits, exploitation characteristics, and other relevant parameters for data-limited stocks (WKLIFE X). ICES Scientific Reports. Report. https://doi.org/10.17895/ices.pub.5985
ICES (2023): Eleventh Workshop on the Development of Quantitative Assessment Methodologies based on LIFE-history traits, exploitation characteristics, and other relevant parameters for data-limited stocks (WKLIFE XI). ICES Scientific Reports. Report. https://doi.org/10.17895/ices.pub.22140260.v1