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)
The IBTS hydrochemical dataset for Quarter 1 is available as a compressed comma seperated file here