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Published on
August 23, 2012

RV Tridens started the annual beam trawl survey last Monday.

The survey started in 1985, primarily to collect data about the abundance of sole and plaice in the North Sea. The format of the survey is constant over years, in order to compare the full time-series. The information from this survey is used for the stock assessment of plaice and sole. For more information on how stock assessments word, see http://www.ices.dk/aboutus/Press%20pack/ICES%20FB%20210307.pdf. A Dutch television program created a nice overview of the work on board: http://www.willemwever.nl/vraag_antwoord/dieren-en-planten/hoe-worden-vissen-op-de-zee-geteld

Photo 1: Kees and Bert collecting otoliths from which the age of the fish can be determined
Photo 1: Kees and Bert collecting otoliths from which the age of the fish can be determined

During the beam trawl survey we carry out 30 minute tows and we fully sort the catch. This results in more information than sole and plaice only. All data are entered into the computer, and so, kilo’s of fish and other species transform into lists with numbers. That sounds pretty boring, but practical it is.

Photo 2: Lorna and Mascha entering data into the computer
Photo 2: Lorna and Mascha entering data into the computer