Research

Working Group on Nephrops Surveys (WGNEPS ; outputs from 2020)

In ICES Scientific Report, 2021

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Abstract

The Working Group on Nephrops Surveys (WGNEPS) is the international coordination group for Nephrops underwater television and trawl surveys within ICES. This report summarizes the national contributions on the results of the surveys conducted in 2020 together with time series covering all survey years, problems encountered, data quality checks and technological improvements as well as the planning for survey activities for 2021. In total, 19 surveys covering 25 functional units (FU’s) in the ICES area and 1 geographical subarea (GSA) in the Adriatic Sea were discussed and further improvements in respect to survey design and data analysis standardization and the use of most recent technology were reviewed. Due to the COVID-19 pandemic there were disruptions across several functional units to: survey operations (FU 30, GSA 17, FU 10, FU 13 – Jura, FU 34, FU 28-29); data processing (FU 23-24) and survey coverage (FU 9). Further results from field studies on behaviour aspects of burrow emergence using bottom cages monitored by an automated camera system and on short-range migration using acoustic tracking and remote operated vehicle (ROV) surveys in marine protected areas have become available and are summarised in this report. Geostatistical investigations to reduce uncertainty estimates showed comparable results to historical trends for one survey area in the North Sea. Other preliminary work to redefine survey area using best available datasets was also discussed. Reference sets compilation and count evaluations using still image annotations and Lin’s concordance correlation coefficient (CCC) quality control were presented. Automatic burrow detection based on deep learning methods applied to a test dataset with annotated burrow counts from a HD camera system from two projects showed promising results. The working group members were encouraged to provide more material with annotated burrow counts for further development of machine learning tools. An underwater television (UWTV) survey manual has been accepted for publication in the ICES Techniques in Marine Environmental Sciences (TIMES) series. The working group is currently developing plans for a Nephrops UWTW database to be established at the ICES data centre.