Workshop on ICES reference points (WKREF2)

• Main Authors: Orio, Alessandro, Kempf, Alexander, Pierucci, Andrea, Kuparinen, Anna, Rindorf, Anna, Peyronnet, Arnaud, Wilson, Ashley, Albertsen, Christoffer Moesgaard, Konrad, Christoph, Sparrevohn, Claus Reedtz, Minto, Cóilín, Howell, Daniel, Gilljam, David, Miller, David, Garcia, Dorleta, Armelloni, Enrico, Abad, Esther, Masnadi, Francesco, Scarcella, Giuseppe, Dingsør, Gjert Endre, Winker, Henning, Sparholt, Henrik, Farias, Inês, Horbowy, Jan, Lecomte, Jean-Baptiste, Hutchings, Jeffrey A., Fall, Johanna, Lövgren, Johan, Simmonds, John, Shrives, Jonathan, De Oliveira, José, Hommik, Kristiina, Kell, Laurence, Vansteenbrugge, Lies, Borges, Lisa, Batts, Luke, Taylor, Marc, Pastoors, Martin, Scanu, Martina, Cardinale, Massimiliano, Gras, Michaël, Deurs, Mikael van, Goñi, Nicolas, Graham, Norman, Silvar Viladomiu, Paula, Sampedro, Paz, Hilborn, Ray, Sharma, Rishi, Millar, Sarah, Nimmegeers, Sofie, Miethe, Tanja, Perälä, Tommi, Bartolino, Valerio
• Other Authors: Lordan, Colm
• Format: Book
• Language: English
• Published: International Council for the Exploration of the Sea (ICES) 2022
• Subjects: North East Atlantic
• Online Access: https://orbit.dtu.dk/en/publications/8acee456-556d-4193-98b2-45d27dfd7e4f; https://doi.org/10.17895/ices.pub.20557008; https://backend.orbit.dtu.dk/ws/files/284289240/WKREF2_2022.pdf

The ICES Workshop on ICES reference points (WKREF2) was tasked review the WKREF1 report and based on the outcome develop updated guidelines for the ICES reference points system and recommendations for ACOM consideration. The WKREF1 report has suggested 5 key recommendations to simplify and harmonise the ICES reference points framework representing a major change to the current guidelines. At WKREF2, we detailed discussions and four key concerns were raised about the proposed approach. The first related to the simplification of rules to define B lim . Around two thirds of category 1 stocks would end up as WKREF1 “B lim Type 2” where Blim would be set as a fraction of B0. The Allee effect or “depensation” maybe more important than previously thought and should be furthered explored for ICES stocks since it has important consequences for B lim . A number of challenges and issues around defining B lim using the current guidelines were documented. Some suggestions on improvement criteria were discussed including using classifiers to define spasmodic stocks and using change point algorithms to address non-stationary productivity regimes. However, further work is need to make these approaches operational and there was no consensus that the WKREF1 B lim types should replace the current guidelines. WKREF1 recommended that the F MSY proxy should be based on a biological proxies and should be less than the deterministic F MSY . It was pointed out that the stochastic F MSY estimated in EqSim for example, is lower than the deterministic F MSY and that the current guidelines ensure that the F MSY should not pose a more than 5% risk to B lim . A large amount of work described in WD 1 was carried out to develop an MSE framework to consistency and robustness test a candidate reference point system for North East Atlantic stocks. However, WKREF2 recommended that further work needs to be carried out to condition and test the simulation framework before the conclusions could be adopted by ICES and incorporated into the guidelines. ...