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

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.