Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Clupea	338	09.10.2019 - 01.11.2019	BIAS	Baltic Sea

Fahrtleiter Chief Scientist	Institut Institute	Auslaufhafen Port of departure	Einlaufhafen Port of return	Stationskarte Station map	Schiffsroute Trackchart
Schaber Matthias	Thunen-Institut fur Ostseefischerei	Rostock	Rostock	Karte Map

Ziel der Reise / Objectives of Cruise:

Clupea 338: Leg one: The main aim of the first part of the cruise was hydroacoustic monitoring of clupeid distribution in the Sound and adjacent areas: Estimation of distribution and stock size parameters of small pelagics (herring and sprat) contributing to concurrent investigations (FRV "Solea") in the framework of an international, ICES-coordinated hydroacoustic survey. Due to several reasons, the investigations in the Sound-area had to be shortened both in time and sampling effort. Nevertheless, it was possible to collect hydroacoustic data to investigate the distribution of clupeid fishes in the area in support of the Baltic International Acoustic Survey (BIAS). A preliminary analysis revealed differences in abundance and distribution between day and night, as well as inhomogeneous distribution of clupeids in the Sound with relative high abundances also occurring in shallower areas, currently not covered by the BIAS. The results of the cruise will help to discuss methodological questions in relation to BIAS, especially day/night effects in the Sound and distribution of clupeid fishes in shallower areas. Leg two: During the second part of the cruise, new selectivity devices for trawls were developed and tested in German waters (off the coast of Rostock). The background for these efforts are the current poor stock status of the Eastern Baltic cod stock and the resulting implications for fisheries in the Eastern Baltic Sea as well as in SD24. The aim was to develop selectivity devices, which allow cod to escape, while keeping the catch of flatfish high. These investigations were conducted via underwater video observation of the selectivity devices and their modifications. It was possible to develop escapement devices/concepts and prepare for further tests on commercial vessels and later research cruises. The cruise was conducted in the framework of the CODEX-project, funded as EMFF-project by the EU and the ?Ministerium fur Landwirtschaft und Umwelt Mecklenburg-Vorpommern'

Messungen / Measurements