EU request to provide guidance on operational methods for the evaluation of the MSFD criterion D3C3 (second stage 2017)
reportposted on 2022-02-02, 10:11 authored by ICESICES
ICES advises that the data currently collected on fish length for stock assessment purposes is suitable to assess the size distribution of a stock. ICES advises that there is a need to further test three potential indicators for D3C3 (the age and size distribution of individuals within commercially exploited stocks) that focus on the large spawning fish within each considered stock. To derive reference levels and possible assessment thresholds, population models can be used to simulate fishing scenarios in accordance with good environmental status under D3C1 and D3C2. In a second stage, the age-based indicator concepts could be transferred to size-based calculations to enable a wider application to those stocks that do not have ageing information.
Until the proof of concept has been validated, ICES recommends that D3C3 be considered as a surveillance indicator for size distribution and that several time-series assessment methods may be appropriate to track relative changes in the indicator metrics.