The rationale for heterogeneous inclusion of ecosystem trends and variability in ICES fishing opportunities advice

Abstract

Incorporation of ecosystem information into fish stock assessments and management advice, a cornerstone of delivering ecosystem-based fisheries management (EBFM), occurs often implicitly, faces multiple challenges, and remains often unquantified in terms of scope and scale. This paper provides a comprehensive overview of the inclusion of ecosystem trends and variability in ICES fishing opportunities advice in the Northeast Atlantic, by covering 87% of stocks corresponding to 99% of landings. Just under 50% of all stock assessments considered ecosystem information and the majority of management strategy evaluations did so in at least one way. Almost 73% of the data-rich stocks incorporated ecosystem trends and variability in at least one way, and almost 55% of short-term forecasts did so. Stock (individual growth rate) and fisheries (landings) characteristics largely explained the observed patterns of incorporation of ecosystem information into advice, with pelagic species and stocks with higher landings having higher instances of incorporation. Early stages of the advice process (closer to data analysis and methods development) had greater inclusion of ecosystem information, though this inclusion was generally implicit and not explicit, e.g. based on a hypothesis of environmental influence on stock dynamics. Moving towards explicit instructions and routine documentation of the inclusion of ecosystem information in fishing opportunities advice will accelerate the path to the EBFM in a consistent and transparent manner.

Can regime shifts in reproduction be explained by changing climate and food availability?

“…Our forecasting capacities using environmentally mediated SR models, however, remain generally insufficient to improve tactical management advice (Stige et al, 2013;Subbey et al, 2014;King et al, 2015;Haltuch et al, 2019;Maunder and Thorson, 2019;Uriarte et al, 2023). Fisheries management advice in the Northeast Atlantic (NEA), for instance, showed that environmentally driven recruitment is implemented in none of the 230 studied stock assessments, and in only 11 out of 102 short-term forecasts (Trenkel et al, 2023). Tactical operational management advice therefore uses alternative approaches to account for changes in productivity (Collie et al, 2021;Silvar-Viladomiu et al, 2021;Trenkel et al, 2023).…”

“…Fisheries management advice in the Northeast Atlantic (NEA), for instance, showed that environmentally driven recruitment is implemented in none of the 230 studied stock assessments, and in only 11 out of 102 short-term forecasts (Trenkel et al, 2023). Tactical operational management advice therefore uses alternative approaches to account for changes in productivity (Collie et al, 2021;Silvar-Viladomiu et al, 2021;Trenkel et al, 2023). These alternative approaches are required when the available data are insufficient to estimate SR models (Conn et al, 2010;Nesslage and Wilberg, 2019), but are also used in data-rich assessments by focusing on empirical methods without knowing the underlying ecological mechanism.…”

“…Nishijima et al, 2021;Stock and Miller, 2021;Su, 2023), and the truncation of the recruitment time series to recent productivity conditions (Van Deurs et al, 2021;Silvar-Viladomiu et al, 2022b). Environmentally mediated SR models were, contrastingly, used in most of the scientific advice for rebuilding plans in the NEA (24 out of 30, Trenkel et al, 2023). Indeed, the need for continual mechanistic insights at broader level is recognized and required to inform strategic management in the longer term (Silvar-Viladomiu et al, 2022a;Kjesbu et al, 2023), for instance for the evaluation of climate-adaptive management measures (e.g.…”

A roadmap to reduce the risk of overexploiting EU marine living resources in a changing ocean

“…To mitigate the risks in fisheries, it is essential to integrate climate impact knowledge into stock assessment and forecasts, to re-evaluate stock boundaries and data collection systems when mismatches arise due to a changing climate affecting stock distribution, timing of biological processes, natural mortality rates, invasive species, etc., with a dynamic monitoring and management approach (Table 2 A9). Accounting for climate change-induced effects on past trajectories of stock development is also vital for accurately incorporating these impacts in the possible explanatory variables (Trenkel et al, 2023). Additionally, offering fishing companies more flexibility regarding fishing opportunities could help safeguard against drastic changes in species availability and accessibility.…”

“…One immediate action includes accounting for the outcomes of multispecies assessments when setting fishing opportunities. The (Trenkel et al, 2023).…”