Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Walther Herwig III	WH464	20.01.2023 - 21.02.2023	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	Bremerhaven

Ziel der Reise / Objectives of Cruise:

The cruise was part of the International Bottom Trawl Survey (IBTS), which is an internationally coordinated ICES program aiming to provide fish population data and biological 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, 22 GOV hauls were taken during the cruise (67 planned hauls) accompanied by 22 CTD profiles. Standardized total catches of the GOV hauls were on average about 485 kg/30min. Highest prerecruit number were found for herring <20cm (256685 ind./hr.) and lowest for cod <25cm (16 ind./hr.). In addition, 80 MIK plankton samples were taken (134 planned hauls) providing abun-dance estimates for large herring larvae (0-ringers) of the autumn spawning stock com-ponents. Standard length (SL) of herring larvae from the night time MIK sampling varied between 12- and 34mm (German data). In total, abundance of large herring larvae in the potential nurseries was lower than last year. The index from the 2023 survey (corre-sponding to the 2022 year-class) is 90.8 and is a bit below the long-term average of 100.7. Additional work was done on stomach collection (63 samples), cod liver worms (53 samples), haddock gill parasites (1006 samples) and starry smooth hound genetics (25 samples).

Messungen / Measurements