Many ICES expert groups use data on fishery catches to describe fishing activities, show the development of fisheries, and evaluate the impacts of fisheries on stocks and ecosystems. Data from fisheries are often are the primary basis for reconstructing historical populations and estimating fishing mortality. These data are often treated as exact in fish stock assessments; however the data are of variable quality. Reported landings may be inaccurate to varying extents over time, and there is bias and uncertainty associated with sampling of fishery catches. These translate into inaccuracies in advice. It is vital that ICES or other end users can have confidence in the fishery data underpinning stock assessments and advice on sustainable fishing, and understand their limitations.
Making sure that the data are collected using statistically-sound sampling designs is a key first step, and ICES has provided extensive guidelines on this through a wide range of Expert Groups dealing with the statistical and practical aspects of sampling fishery catches. The work of all these groups forms the foundation for the ICES Working Group on Commercial Catches (WGCATCH). WGCATCH will continue to document national fishery sampling schemes, establish best practice and guidelines on sampling and estimation procedures, and provide advice on other uses of fishery data (e.g. developing relative abundance indices based on fishery catch rates). The group will also evaluate how new data collection regulations, or management measures (such as the landings obligation) will alter how data need to be collected and provide guidelines about biases and disruptions this may induce in time series of commercial data. WGCATCH will also continue to develop and promote the use of a range of indicators of fishery data quality for different types of end users. These include indicators to allow stock assessment and other ICES scientists to decide if data are of sufficient quality to be used, or how different data sets can be weighted in an assessment model according to their relative quality.
WGCATCH is attended by over 40 members from over 15 countries. It aims to bring together the best expertise in fishery data, sampling design and analysis available in the ICES community. If you would like to join WGCATCH please contact your national ICES Delegate.
WGCATCH members, Greece, 2017