The ICES International Bottom Trawl Survey (IBTS) in the North Sea has been undertaken during January/February since about 1970. Part of this survey includes station observations of hydrochemical measurements which has resulted in a most comprehensive dataset of the North Sea.Prior to 1993 the IBTS surveys were known as the International Young Fish survey (IYFS).New cruises will be added every year. See 'Other version' for the IBTS hydrochemical dataset for Quarter 1 in compressed comma seperated file format.