This report reviews, describes and evaluates the different monitoring options that are available for obtaining counts of the number of cetacean bycatches that occur in European fisheries. Three methods were adjudged able to obtain these data: self-reporting by fishers, at-sea observers, and remote electronic monitoring (REM) systems with CCTV. Of these, only the data collected by at-sea observers or REM can be collected independently of the fishers and only REM allows later verification of the bycatch events as often as required.

Therefore, in this report these two methods are more fully described and compared against each other in terms of ability to collect the required data and of the costs associated with running a cetacean monitoring programme. A description of the different components associated with electronic monitoring was also presented as there has often been confusion about what constitutes electronic monitoring and electronic recording and why a verification tool is necessary. Only a REM system with integrated satellite tracking, fishing activity sensors, and closed-circuit television cameras (CCTV), was considered a full remote electronic monitoring system with verification.

The report also lists possible recommendations and future developments related to the use of REM as a monitoring tool for ETP (endangered, threatened, protected species) bycatch.

Grant P. Course (2021). Monitoring Cetacean Bycatch: An Analysis of Different Methods Aboard Commercial Fishing Vessels. ASCOBANS Secretariat, Bonn, Germany. 74 pages. ASCOBANS Technical Series No.1.