Cruise report Hywind Tampen 13 to 28 March 2023 - Cruise no. 2023001004 G.O. Sars

Abstract

There is very little knowledge related to how floating windfarms effect the marine environment as this is such a new “product”. Thus, the data that we gathered on this cruise will be novel in that sense. The aim of the cruise was to look at possible effects of the windfarm on the marine environment. Based on limited cruise time and tough weather conditions around Hywind Tampen we had to be selective related to topics for this first cruise, and we choose to focus on the following: 1) Measuring noise from the turbine. This we did by deploying a hydrophone mooring within the windfarm. 2) Measuring current to track possible changes in current and wake effect. We did this by deploying ADCP’s within and around the windfarm, and by conducting CTD transects around and within the windfarm. 3) Look at possible effects on pelagic fish distribution, by conducting acoustics transects with RV G.O. Sars's multi-frequency acoustics, within and around the windfarm. As the RV G.O. Sars is not allowed closer then 500m to the turbines, we conducted acoustic transects with an acoustic kayak-drone within the 500 m range to the wind turbines. The kayak being allowed as close as 15-20m to the turbines. To able ground truthing of acoustic findings we trawled with an open trawl equipped with a camera (DeepVision) and we took eDNA samples along the transects. 4) Effect of bottom structure on the benthic fauna. This was studied by ROV transects filming fauna around 3 suction anchors and the adjacent chains connecting the turbines to the anchor. ROV control transects were conducted from the very same suction anchors, but on a line moving away from the windfarm. This cruise was conducted in collaboration with the NFR-funded WindSys project.