Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Walther Herwig III	WH443	25.01.2021 - 15.02.2021	IBTS	North Sea

Fahrtleiter Chief Scientist	Institut Institute	Auslaufhafen Port of departure	Einlaufhafen Port of return	Stationskarte Station map	Schiffsroute Trackchart
Neumann Hermann	Thunen-Institut fur Seefischerei	Bremerhaven	Wilhelmshaven	Karte Map

Ziel der Reise / Objectives of Cruise:

The cruise was part of the International Bottom Trawl Survey (IBTS), which is an inter-nationally coordinated ICES program aiming to provide fish population data and biolog-ical parameters of commercial fish species for stock assessment purposes. Sampling of fish was conducted by trawl hauls in allocated ICES statistical rectangles by means of the ICES standard bottom trawl GOV. In total, 67 GOV hauls were taken during the cruise. Fish sampling was accompanied by taking 67 CTD profiles, 144 MIK plankton samples and 36 microzooplankton samples. Standardized total catches of the GOV hauls were on average about 347 kg. Highest pre-recruit number were found for mackerel <25cm (248469 ind./hr.) and lowest for cod <25cm (6 ind./hr.). Except for cod and herring, all recruitment indices of the major target species haddock, whiting, Norway pout, sprat and mackerel were higher than the long-term average from 1980-2020. Standard length (SL) of the herring larvae from the night time MIK sampling var-ied between 7- and 41-mm. Abundance of large herring larvae in the potential nurse-ries was lower than last year. The 2021 index for the 2020 year-class is 95.2, which is higher than for the 2019, but still much lower than observed in the early and late 1990s.

Messungen / Measurements