COMMON WHELK Buccinum undatum
Publication of Advice: 7. June 2024. Published by Marine and Freshwater Research Institute.
Advice
MFRI advises in accordance with the MSY approach that catches in the fishing year 2024/2025 should be no more than 190 tonnes in Breiðafjörður.
Stock development
Fishing pressure on the stock is below Flim and above FMSY and the stock biomass is above Blim and Btrigger.
Common whelk. Catches, changes in relative biomass (B/BMSY) and relative fishing mortality (F/FMSY). Shaded areas represent 95% CI.
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 | Surplus production model (SPiCT) |
Input data | Catch and standardized CPUE |
Approach | Reference point | Value | Basis |
|---|---|---|---|
MSY approach | MSY Btrigger | 0.5 | A fraction of BMSY where production is 50% of MSY |
FMSY | 1.0 | Fishing mortality values expressed relative to FMSY | |
Precautionary approach | Blim | 0.3 | A fraction of BMSY where production is 50% of MSY |
Flim | 1.7 | Fishing mortality which results in median SSB at Blim |
Prospects
Common whelk. Assumptions made for the interim year and in the forecast.
Variable | Value | Notes |
|---|---|---|
Projected catch (2024) | 192 | Short term forecatch under Fsq; in tonnes |
Stock size B2025/BMSY (2025) | 0.88 | Short-term forecast at status quo F (Fsq); in tonnes |
Fishing mortality F2023/FMSY (2024) | 0.7 | Status quo F: F2023/FMSY |
Common whelk. Projection of biomass (tonnes) based on the MSY approach
Basis | Catch (2024/2025) | Fishing mortality (2025) | Stock size (2026) | % Biomass change | Advice change |
|---|---|---|---|---|---|
MSY approach: FMSY | 190 | 0.6978 | 0.89 | 2 | -3 |
Quality of the assessment
The basis for the assessment was changed in 2023. The assessment is now based on a surplus production model (SPiCT). The input data for the assessment model are total catch and standardized CPUE´s from Breiðafjörður, where spatial and temporal changes in catches are accounted for. The assessment of common whelk was updated last year and is based on a surplus production model (SPiCT).*
Common whelk Current assessment (red line) compared with previous estimates 2023–2023
Ráðgjöf, aflamark og afli – Advice, tac and catch
Common whelk. Recommended TAC, national TAC, and catches (tonnes).
Fishing year | Recommended TAC | National TAC | Total catch |
|---|---|---|---|
2012/2013 | 750 | 269 | |
2013/2014 | 750 | 0 | |
2014/2015 | 750 | 166 | |
2015/2016 | 750 | 332 | |
2016/2017 | 750 | 186 | |
2017/2018 | 500 | 171 | |
2018/2019 | 500 | 324 | |
2019/2020 | 220 | 133 | |
2020/2021 | 264 | 88 | |
2021/2022 | 264 | 239 | |
2022/2023 | 254 | 268 | |
2023/2024 | 196 | ||
2024/2025 | 190 |
References and further reading
Pedersen, M. W., & Berg, C. W. (2017). A stochastic surplus production model in continuous time. Fish and Fisheries, 18(2), 226-243.
ICES. 2022. ICES technical guidance for harvest control rules and stock assessments for stocks in categories 2 and 3. In Report of ICES Advisory Committee, 2022. ICES Advice 2022, Section 16.4.11. https://doi.org/10.17895/ices.advice.19801564
MFRI Assessment Reports 2024. Common whelk. Marine and Freshwater Research Institute, 7 June 2024. Stofnmatsskýrslur Hafrannsóknastofnunar 2024. Beitukóngur. Hafrannsóknastofnun, 7. júní 2024.