Discards monitoring in the gillnet fishery for sole

Approximately 2-3% of the Dutch fishing quota for sole (Solea solea) is caught by a 60-vessel strong inshore fleet of gillnetters. From their home ports in IJmuiden, Scheveningen and Den Helder, these vessels fish typically with bottom-set gillnets for sole during 1 day trips between March and October. Sole caught by gillnetters is typically of good quality and reserves a niche in the market. Some of the vessels are certified with the Marine Stewardship Council (MSC) or Friends of the Sea (FOS). As a condition of these certificates, fishers self-report via logbooks during each trip the kg landings and count the number of discards by species. Under the European Data Collection Framework (DCF), gillnetters qualify to be monitored by observers. However, their deployment is often difficult due to a lack of space on board, in particular for vessels smaller than 12 m length. In 2013, for the first time, two trips for sole were accompanied by an observer from IMARES. In 2011 as part of a pilot project, an electronic monitoring system (CCTV) was installed onboard a single vessel to monitor the bycatch of harbour porpoises. In this document, data from these three sources (self-reporting, observer trips and CCTV) were used to describe landings and discard compositions. Because IMARES was only involved in setting up the protocol for the self-reporting and analysing the data, IMARES cannot guarantee the validity of the results herein