Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Dana	07/2021 DK/DE IBTS3Q	19.08.2021 - 12.09.2021	IBTS	North Sea

Fahrtleiter Chief Scientist	Institut Institute	Auslaufhafen Port of departure	Einlaufhafen Port of return	Stationskarte Station map	Schiffsroute Trackchart
Wieland Kai	Technical University of Denmark National Institute of Aquatic Resources	Hirtshals	Hirtshals

Ziel der Reise / Objectives of Cruise:

The survey is part of the 3rd quarter International Bottom Trawl Survey (IBTS) in the North Sea, which is coordinated by the ICES International Bottom Trawl Survey Working Group and has been conducted with standard fishing gear in the 3rd quarter since 1991. The IBTS aims to provide ICES assessment and science groups with consistent and standardised data for examining spatial and temporal changes in (a) the distribution and relative abundance of fish and fish assemblages; and (b) of the biological parameters of commercial fish species for stock assessment purposes. The main objectives in the 3rd quarter IBTS are to: - To determine the distribution and relative abundance of pre-recruits of the main commercial species (cod, haddock, whiting, Norway pout, saithe, herring, sprat, and mackerel) with a view of deriving recruitment indices; - To monitor changes in the stocks of commercial fish species independently of commercial fisheries data; - To monitor the distribution and relative abundance of all fish species and selected invertebrates; - To collect data for the determination of biological parameters for selected species; - To collect hydrographical and environmental information. - To collect information of the amount and distribution of marine litter The area to be covered by Denmark with RV Dana in the 3rd quarter 2017 was allocated during the IBTS Working Group meeting in April 2017. Technical details are described in the current version of the survey manual (ICES 2015. Manual for the International Bottom Trawl Surveys. Series of ICES Survey Protocols. SISP 10-IBTS IX. 86 pp.). Additional requests from the IBTS WG for the 3Q survey in 2017 were to collect information on the trawl setting and retrieval duration of the standard 30 min tows and to conduct so called zero-minute tows in order to estimate the catch obtained outside the nominal tow duration of the standard tows in respect to depth.

Messungen / Measurements