Working group on Fisheries Acoustics, Science and Technology (WGFAST).

The ICES Working Group on Fisheries Acoustics, Science and Technology (WGFAST) is the ma-jor international forum where individuals working in fisheries acoustics network to discuss on-going developments in the technique. As such, it is highly successful, attracting 93 participants from 21 countries to its 2019 meeting in Galway, Ireland from 29 April – 2 May. Highlights The major themes addressed during the WGFAST meeting included: •Behaviour; •Acoustic properties of marine organisms; •Emerging technologies, methodologies, and protocols; •Applications of acoustic methods to characterize ecosystems. A separate session was held for each theme, where the participants first presented the latest re-sults of their work, followed by a discussion. The abstracts and discussion summaries are given in the report. The contributions highlighted the wide range of applications of acoustics for eco-system characterization and monitoring, as well as for abundance surveys. Advancing acoustic technology and alternative sampling platforms (e.g. autonomous vehicles, ocean observatories) have led to increases in the volume of acoustic data being collected. This has created opportuni-ties for wider ecosystem research, but also challenges for data processing and storage. Several presentations highlighted research and increasing applications of acoustic wideband technologies. WGFAST organised training courses on 'Principles and Methods of Broad-band/Wideband Technologies: Application to fisheries acoustics' in 2017 and 2018, with another planned in December 2019. Wideband systems are expected to replace the current standard nar-rowband scientific echosounders, and recent research quantified the impact of this change on abundance surveys. There is increasing interest in using acoustics to characterize and monitor other ecosystem com-ponents, particularly mesopelagic organisms. Mesopelagic resources are large, relatively poorly known, and there is considerable interest in commercial exploitation. Presentations highlighted challenges for acoustics, and the need to apply multiple complementary technologies (acoustics, optics, net sampling) to improve our understanding. A workshop on the development of practi-cal survey methods for measurements and monitoring in the mesopelagic zone (WKMesoMeth) was held in conjunction with the 2019 WGFAST meeting. A joint session was held with the South Pacific Regional Fisheries Management Organization (SPRFMO) Habitat Modelling Working Group during the WGFAST meeting on 30 April 2019. The Ambassador of Peru to Ireland, Ms Ana Sánchez, visited during the meeting. WGFAST co-chaired theme session J at the 2018 ICES Annual Science Conference on “Survey data products for stock and ecosystem assessments: challenges and future directions”. This ses-sion had 24 oral presentations and 8 posters and was attended by about 80 people. Key themes were survey design and the use of survey products in stock assessment. The group concluded that survey scientists and stock assessment modellers need to work in close collaboration to en-sure correct model specifications and interpretations accounting for survey design and method-ology. The second meeting of the topic group on collecting Quality Underwater Acoustic Data in Inclement Weather’ (TG-QUAD) was held in conjunction with the 2019 WGFAST meeting and good progress was made towards production of a Cooperative Research Reports (CRR)