Report of the Second Workshop on the Impact of Ecosystem and Environmental Drivers on Irish Sea Fisheries Management (WKIrish2)

WKIrish 2 is the second in a series of meetings leading to a regional ecosystem as-sessment for the Irish Sea. The series comprises WKIrish1 (September 2015: Infor-mation sharing and scoping), WKIrish2 (September 2016: Data evaluation; WKIrish3 (January 2017: Single-species stock assessment development; and WKIrish4 (date to be confirmed: Development of an integrated ecosystem assessment and advice).WKIrish2 reviewed data and parameters for use in full benchmark stock assessments of Irish Sea whiting, cod, haddock and plaice. Herring was included mainly to evalu-ate a new industry–science acoustic survey dataset. The ToRs for WKIrish2 follow the guidelines for ICES benchmark data evaluation meetings drawn up in 2015 by the ICES Planning Group on Data Needs for Assessments and Advice (PGDATA). These covered stock identification, biological parameters (natural mortality, growth, ma-turity), fishery catch and length/age composition data, and survey data on relative abundance. The Workshop compiled and evaluated information on the historical na-tional fishery sampling schemes and sampling achievements, to support decisions on inclusion and weighting of dataseries. A particular issue for Irish Sea whiting, had-dock and plaice is high discard rates for which estimates are only available since the mid-2000s. WKIrish2 reviewed sampling levels by country and gear and identified years with sufficient samples (given the national fleet contributions to total discards) to compute fleet-raised discards. Time-series of discard ogives were compiled to help inform modelling approaches that can extrapolate historical discarding where there are few data. Very large changes in demersal fleet structure and effort have occurred in the Irish Sea which can lead to large changes in selectivity. WKIrish2 evaluated the potential to develop fleet-disaggregated landings and discard estimates, and associ-ated length/age compositions for use in statistical fleet-disaggregated models. The WK drew up a time line of management measures that can affect quality, interpreta-tion and use of fishery data for the stocks, and changes in selectivity.