Walther Herwig III, 406th cruise

Duration:   June 6 – July 4, 2017

Area of investigation: Atlantic southwest of Ireland (Grand Sole Bank)

Purpose: Gear technological investigations in mixed fisheries

Unwanted bycatches are problematic from an economical, ecological and ethical point of view. Therefore, a central aspect of the new EU common fisheries policy (CFP) was the implementation of a landing obligation (discard ban) from 2015 onwards. This means that it is obligatory for fisheries to land all catches (implementation started with some fisheries and TAC-species) and count catches on the relevant quota (TAC). Consequently, this should result in economic incentives for the fishery to reduce unwanted bycatches.

The Thünen Institute of Baltic Sea Fisheries works on different strategies to avoid unwanted bycatches since several years. Here, gear technology plays a central role and several new concepts were developed. Special challenges are fisheries with catches consisting not only of the target species (so called ‘mixed fisheries’). Since these species often have different morphological properties, as well as different behavior, it is often not possible to offer sufficient escapement possibilities to different species in the codend alone. An example is the unwanted bycatch of flatfish in the roundfish-fishery (e.g. in the Baltic).

Although the developed concepts (e.g. FRESWIND; FLEX; STIPED) were tested and improved in the Baltic Sea, they can be potentially applied to other fisheries worldwide. Consequently, we partly expand the geographical scope of the work to selected other areas and fisheries. Within this context some cruises will be conducted to the North Sea and the waters southwest of Ireland (Grand Sole Bank). Some fisheries in these areas have partly high bycatch rates. It is the aim to reduce the catch of unwanted bycatches in these areas by using the concepts, developed in the Baltic Sea but adapted to the specific needs. The gear technology investigations during this cruise will be conducted on Grand Sole Banks.

A collaborative project between partners from Germany and Spain is being outlined to address the bycatch problem in Celtic Sea (Grand Sole Bank) mixed OTB (Bottom Otter Trawl) fisheries by means of improvements on fishing technology. In particular, the project would be focused on the fleet targeting Megrim, Monkfish and Hake, which discard rate is estimated to be above 50 % of the total catch (estimations by Instituto Espanol de Oceanografia, IEO).

The main aim of this collaboration is to reduce the unwanted bycatch in this fishery through the improvement of codend selectivity. With the aim to almost simulate commercial catch conditions, the spanish partners provide a gear. In addition to the standard-procedure to sample each haul, there will be some additional investigations onboard.

Scientific cruise leader: