ANGLERFISH

Lophius piscatorius


Technical report
Published by

Marine and Freshwater Research Institute, Iceland

Published

6 June 2025

Key signals

  • The biomass index from the spring survey has shown a downward trend since 2010, but has increased significantly in the past three years.

  • Recruitment has been poor since 2010 with the exception of 2025 when recruitment increased substantially.

  • Length distribution has shown an increase in total length since 2010 due to low recruitment resulting in a population consisting of older and larger individuals, with the exception of 2025.

  • Total biomass peaked in 2005 in the SMB survey and seems to be increasing again, following a period of low biomass.

  • Fishing mortality (F) is below FMSY.

GENERAL INFORMATION

Anglerfish (or monkfish) is a benthic "sit and wait" predator that is most abundant south and west of Iceland. It is found at depths from 20-2800 m, though most abundant between 50 and 250 m.

Females grow larger than males and can reach a size of 130 cm while males larger than 80 cm are rare. Similarly, females become sexually mature around 80 cm and males around 61 cm.

The north-western edge of the anglerfish’s habitable area is found in Icelandic waters, which renders it more sensitive to environmental changes than many other species in the area.

The Fishery

In 2017-2021, anglerfish was caught in the southeast, southwest and, to a small extent west of Iceland as reported in logbooks (Figure 1 and Figure 2). From 1995-2000 captures were mostly in the southeast and southwest after which it was captured more frequently in the west and in 2010-2016 also northwest and north of Iceland (Figure 1, Figure 2). Geographic distribution has changed mostly in the form of more aggregated patches because of a large reduction in caches in the southeast, south, southwest, and west areas apart from a large increase in the northwest from 2010-2016. During the past four years, spatial distribution has gradually decreased towards its previous state, before 2000 (Figure 1).

On Icelandic fishing grounds, anglerfish is mostly caught at depths between 50 and 250 m (Figure 3). In 2000-2016 it was captured to a large extent in anglerfish gillnets. Otherwise, bottom trawls and Nephrops trawls were most common until last year when the Nephrops fisheries stopped (Figure 4, Table 1). The number of boats reporting anglerfish catches peaked in 2007, with a total of 472 boats, but annual catch peaked in 2005 at 1631 t. Since then, catches have declined annually amounting to 171 t in 2024. A large reduction in catches between 2016 and 2017 can be explained by a reduction in the anglerfish gillnet fishery which accounted for 54% of the anglerfish fisheries in 2016, 14% in 2017, and 5% in 2022 (Table 1). A reduction from 411 to 159 vessels from 2021-2022, and a significant reduction in total catch, can be explained by a Nephrops fishing ban.

Figure 1: Anglerfish. Geographic distribution of the Icelandic fishery since 1995 as reported in logbooks.
Figure 2: Anglerfish. Catch distribution and proportions by area since 1995 according to logbooks. All gears combined.
Figure 3: Anglerfish. Depth distribution since 2000 according to logbooks.
Figure 4: Anglerfish. Total catches (landings) by fishing gear since 1994 acording to statistics from the Directorate of Fisheries.
Table 1: Anglerfish. Number of Icelandic vessels reporting captures of anglerfish, and landed catch divided by gear type.
Year Nr. Bottom Trawl Nr. Gillnets Nr. Other Nr. Nephrops Trawl Bottom Trawl (t) Gillnet (t) Other (t) Nephrops Trawl (t) Total catch
1995 106 103 102 58 119 41 185 164 509
1996 90 125 120 58 248 45 239 259 791
1997 88 108 134 56 383 60 178 212 833
1998 85 129 122 46 362 69 108 296 835
1999 100 133 119 41 520 50 128 293 991
2000 94 163 177 34 355 765 190 220 1530
2001 76 239 191 36 279 619 211 251 1360
2002 74 207 182 36 184 249 228 309 970
2003 73 187 214 37 184 900 260 341 1685
2004 74 179 213 29 307 1268 295 353 2223
2005 80 129 243 31 452 1495 391 514 2852
2006 68 109 257 28 489 1273 424 405 2591
2007 72 98 256 22 560 1489 436 310 2795
2008 63 87 240 22 381 1690 536 341 2948
2009 63 105 226 17 574 2473 602 419 4068
2010 66 165 217 18 453 1762 510 556 3281
2011 55 170 202 17 300 1991 463 475 3229
2012 59 158 186 18 178 1744 301 444 2667
2013 64 87 170 16 144 859 157 337 1497
2014 57 80 152 16 146 712 93 234 1185
2015 49 55 128 14 145 512 54 223 934
2016 54 43 115 12 156 500 38 200 894
2017 50 40 97 9 130 89 35 213 467
2018 47 35 85 9 248 100 50 244 642
2019 49 32 85 8 240 53 34 181 508
2020 53 25 69 8 192 30 37 177 436
2021 49 31 60 7 147 47 20 196 410
2022 51 21 53 3 122 9 25 2 158
2023 49 18 53 0 166 12 28 0 206
2024 51 15 55 1 158 10 33 2 203

Length distributions from commercial catches

Length measurements from monkfish catches in 2001-2016 and 2019 reveal a change towards dominantly larger individuals after 2012, resulting in larger mean length (Figure 6). Data are however scarce after 2012 due to lower catches resulting in fewer length measurements as they are proportional to the catches.

Figure 5: Anglerfish. Distribution of commercial catches 2024 and sampling location.
Figure 6: Anglerfish. Relative length distribution from commercial catches from the year 1998 excluding years and gears with few or no length measurements.

Survey Data

The annual Iceland spring groundfish survey (hereafter spring survey) has been conducted in March since 1985 and covers the whole Icelandic anglerfish distribution area. An additional autumn groundfish survey (hereafter autumn survey) has been conducted annually from 1996 but does not represent the anglerfish distribution and abundance as well as the spring survey. The autumn survey was not conducted in 2011.

In the surveys, harvestable biomass index is calculated as total biomass of individuals 40 cm and larger. From 1998 to 2005 the harvestable biomass index increased rapidly and remained high until 2011, followed by a sharp decline in the next five years. 2016-2019, the harvestable biomass index was relatively stable but decreased rapidly but with a small increase this year (Figure 7). The recruitment index estimated as abundance ≤ 40 cm, shows a dramatic increase, starting in 1997-1998, but a reduction in recruitment from 2008. Recruitment has since 2010 remained low (Figure 7). These changes resulted in a change in relative length distribution towards smaller mean length in 1995-2010 and larger individuals after that due to a lack of recruitment (Figure 10).

Figure 7: Anglerfish. Total survey biomass index, harvestable biomass index (≥40 cm) and juvenile abundance index (≤40cm). Lines and shaded areas indicate spring survey and red dots and error bars indicate autumn survey. Shaded areas and error bars indicate 95% CI.

Anglerfish is caught in the spring survey mainly to the southeast, southwest, and west of Iceland (Figure 9). The cold waters northeast and east of Iceland are almost completely void of anglerfish. Anglerfish in the northeast are usually caught in the southernmost part. Until 1999, anglerfish was caught almost exclusively south of Iceland after which it was captured in greater numbers in the west and northwest. Since 2016-2017, the relative abundance has decreased in the northwest and west (Figure 9).

Figure 8: Anglerfish. Spatial distribution in the spring survey in 2025 and the autumn survey in 2024.
Figure 9: Anglerfish. Spatial distribution of biomass index from the spring survey since 1985.