Spotted wolffish Anarhichas minor
Publication of Advice: 6 June 2025. Published by Marine and Freshwater Research Institute.
Advice
MFRI advises that when the MSY approach is applied, catches in each of the fishing years 2025/2026 and 2026/2027 should be no more than 299 tonnes.
Stock development
Stock size is just above Itrigger and the fishing pressure is below FMSY proxy.
Spotted wolffish. Catches, IS-SMB juvenile index, fishing pressure proxy and IS-SMB biomass index. IS-SMB biomass index: the red horizontal lines indicate average biomass indices for 2021–2023 and for 2024–2025 used in the advice calculations. Shaded areas and error bars show 95% confidence intervals.
Basis of the assessment and reference points
Basis of the advice | MSY approach |
Management plan | There is no management plan for this stock |
Assessment type | Trends in biomass indicators |
Input data | Commercial catch and survey biomass indices (IS-SMB) |
Approach | Reference point | Value | Basis |
|---|---|---|---|
MSY approach | Itrigger | 3 363 | Iloss×1.4; Iloss defined as the lowest survey value |
FMSY_proxy | 1 | Relative value from LBI analysis, assuming M/K = 1.5 | |
Lc | 59 | Length at first capture, 50% modal abundance from catch length data | |
LInf | 136 | Asymptotic length, defined as maximum length from catch length data | |
K | 0.06 | Population growth rate | |
LF=M | 78.25 | 0.75 x Lc + 0.25 x LInf |
Prospects
The ICES framework for category 3 stocks, for which analytical assessment is not possible but trends in biomass indicators are assumed to reflect changes in stock dynamics, was applied (ICES, 2025). IS-SMB biomass index of Spotted wolffish ≥25 cm is used as an indicator of stock development. As sufficient data on life history in addition to length measurements from catches, the advice is based on the new rfb-rule for ICES category 3 data-limited stocks and is valid for each of the fishing years 2025/2026 and 2026/2027.
Spotted wolffish. Advice calculation.
Ay: Catch advice for 2024/2025 | 296 |
Stock biomass trend | |
Index A (2024-2025) | 3 426 |
Index B (2021-2023) | 3 315 |
r: Stock biomass trend (index ratio A/B) | 1.033 |
Fishing pressure proxy | |
Mean catch length (Lmean = L2024) | 80 |
MSY proxy length (LF=M) | 78 |
f: Fishing pressure proxy (LF=M/Lmean) | 0.972 |
Biomass safeguard | |
Last index value (I2025) | 3 575 |
Index trigger value (Itrigger=Iloss*1.4) | 3 363 |
b: Index relative to trigger value, min{I2025/Itrigger, 1} | 1 |
Precautionary multiplier to maintain biomass above Blim with 95% probability | |
m: Multiplier (generic multiplier based on life history) | 0.95 |
Advice calculation1) | 299 |
Stability clause (+20% / -30% compared to Ay, only applied if b>1)2) | 0 |
Catch advice for 2025/2026 and 2026/2027 | 299 |
% advice change3) | 1 |
1) Ay × r × 1/f × b × m | |
2) min{max(0.7Ay, Ay+1), 1.2Ay} | |
3) The figures in the table are rounded. Calculations were done with unrounded inputs, and compared values may not match exactly when calculated using the rounded figures in the table. | |
Prospects
Considerable uncertainty exists about the prospects of the stock as the level of incoming recruitment is unknown.
Quality of the assessment
The IS-SMB covers the full depth range and geographical distribution of spotted wolffish and the fisheries. Uncertainties and inter-annual variation of survey indices are low. Trends in IS-SMB and IS-SMH survey indices of spotted wolffish are similar.
Other information
The stock is at a critical stage as the biomass and juvenile indices have decreased year on year and are now at historical low levels and near critical thresholds. Therefore, the advised catch levels are expected to decline in the coming years, or potentially a landing ban of spotted wolffish could be advised if the level of fishing mortality is not reduced to values sufficient to reverse the downward trend.
In a Canadian study, the survival rates of released Atlantic wolffish were estimated to be over 90% if released within two hours after catch (Grant and Hiscock, 2014). The authors assumed, due to similarity of these two species, that a similar survival rate could be applied for spotted wolffish. Research conducted by the Marine and Freshwater Research Institute has confirmed this for spotted wolffish caught in bottom trawl. A study on the survival rates of spotted wolffish caught and released by longline is ongoing, the results at present suggest that survival rates are high.
In 2020, a licence was granted for the release of spotted wolffish after catch. Captains are strongly encouraged to record the number of spotted wolffish released in the catch logbooks.
Advice, tac and catch
Spotted wolffish. Recommended TAC, national TAC, and landings (tonnes)
Fishing year | Recommended TAC | National TAC | Total catch |
|---|---|---|---|
2012/2013 | 900 | 2 042 | |
2013/2014 | 900 | 2 250 | |
2014/2015 | 900 | 1 655 | |
2015/2016 | 900 | 1 913 | |
2016/2017 | 1 128 | 1 587 | |
2017/2018 | 1 080 | 1 553 | |
2018/2019 | 1 001 | 1 001 | 1 425 |
2019/2020 | 375 | 375 | 1 310 |
2020/2021 | 314 | 314 | 1 295 |
2021/2022 | 377 | 377 | 904 |
2022/2023 | 334 | 334 | 661 |
2023/2024 | 296 | 296 | 745 |
2024/2025 | 296 | 296 | |
2025/2026 | 299 | ||
2026/2027 | 299 |
References and further reading
Grant, Scott M, and Wade Hiscock. 2014. Post-Capture Survival of Atlantic Wolffish (Anarhichas Lupus) Captured by Bottom Otter Trawl: Can Live Release Programs Contribute to the Recovery of Species at Risk? Fisheries Research 151: 169–76.
ICES. 2025. ICES Guidelines - Advice rules for stocks in category 2 and 3. Version 3. ICES Guidelines and Policies - Advice Technical Guidelines. 31 pp. https://doi.org/10.17895/ices.pub.28506179
MFRI Assessment Reports 2025. Spotted wolffish. Marine and Freshwater Research Institute, 6 June 2025.