The main purpose of this sampling was to study the effects of the OWEZ windpark on the demersal fish community. Because before installation of the windfarm the main fisheries activity in the area was bottom trawling, it is expected that exclusion of fisheries in the wind farm has the largest effect on the demersal fish community. The wind farm and its safety zone could function as a refugium for these species. If the area functions as a refugium this could be the case for a large number of demersal fish species that occur in the Dutch coastal zone. Owing to this a positive effect of the wind farm on the demersal fish community was expected. The fisheries that occurred in the area targeted larger fish, therefore fisheries mortality was higher on the larger fish. By excluding fisheries in the farm it was expected to change the size distribution in the farm and by that the age distribution of the fish populations. A Hydrolab minisonde, attached to the net, was used for continuous CTD measurements.

This study focuses on the behaviour of fish in response to the operation of the wind farm. Wind farms can have either negative or positive effects on fish, for instance by disturbance due to noise or by acting as a refuge because fisheries are banned within the wind farm. An important feature to determine if positive effects might occur is residence time. The longer individual fish spend in the wind farm, the stronger potential benefit of wind farms can be expected. To our knowledge this is the first study on individual behaviour of fish within wind farms. To study the potential effects of wind farms on fish behaviour, we used two approaches: tagging experiments using Peterson disc tags(mark-recapture) and telemetry experiments by following individual fish with small transmitters (VEMCO) in time. We selected two target fish species that are important for fisheries: sole Solea vulgaris as a target species potentially representing fish that use sand habitats and Atlantic cod Gadus morhua as a target species potentially representing fish that use artificial reefs such as the monopile and scour bed habitats in the wind farm. For the tagging experiment, sole was collected with a beam trawl and for the telemetry cod was caught using fising-rods.

The data contains a series of bathymetry measurements performed during the extension of the port of Rotterdam (Maasvlakte 2). The measurements were performed at the site where the dredgers collected the sand. Data are gathered with:Multi-beamSide scan SonarMagnometerData is available at various resolutions:1 x 1 m (sonar)5 x 5 m (sonar)20 x 20 m (multi-beam)2.5 x 2.5 km (multi-beam aggregate)

This resource contains the following two datasets:19 Mp4/avi files containing clips of modelresults, including descriptive excel file1 excel file containing data on dipole source level spectra that were determined for the TSHDs at Maasvlakte 2Furthermore several reports are available.Taken from summary of TNO-DM_2012 R10818.PDFThe Port of Rotterdam is expanding to meet the growing demand to accommodatelarge cargo vessels. The construction of Maasvlakte 2 (MV2) started in September2008. The ‘Milieueffectrapport Aanleg Maasvlakte 2’ [1] provided a preliminaryassessment of the underwater sound produced during the construction of MV2.One of the licence conditions for Maasvlakte 2 is the monitoring of the underwatersound produced during its construction [2], with an emphasis on the establishmentof acoustic source levels of the Trailing Suction Hopper Dredgers (TSHDs) duringthe various activities at MV2: dredging, transport and discharge of sediment.TNO carried out measurement and analysis activities for this monitoring. During aninitial measurement campaign in September 2008, background measurements wereperformed in the absence of dredging. Those earlier measurements are describedin [3]. Source level and background noise measurements were made between22 September and 1 October 2009 in the MV2 dredging activities area.The measurement procedures are described in [4]. Analysis and results for the2009 measurements are reported in [5].[1] G.J.M. Meulepas, G.C. Duyckinck Dörner en W.C. van der Lans, 2007,Milieueffectrapport Aanleg Maasvlakte 2, Bijlage Milieukwaliteit, available athttp://www.maasvlakte2.com/kennisbank/Milieukwaliteit.pdf (last accessed 4October 2011)[2] Havenbedrijf Rotterdam N.V., Projectorganisatie Maasvlakte 2, 2008,Monitoringsplan Aanleg Maasvlakte 2, available athttp://www.maasvlakte2.com/kennisbank/2008-08 Monitoringsplan AanlegMaasvlakte 2 .pdf (last accessed 4 October 2011)[3] J. Dreschler, M.A. Ainslie, W. Groen; Measurements of underwaterbackground noise Maasvlakte 2, TNO-DV 2009 C212, May 2009, available athttp://www.noordzeeloket.nl/overig/bibliotheek.asp (last accessed 20 February2012)[4] P.A. van Walree, M.A. Ainslie, W. Groen; Measurement plan underwatersound Maasvlakte 2, TNO-DV 2008 C302, update, February 2009[5] C.A.F. de Jong, M.A. Ainslie, J. Dreschler, E. Jansen, E. Heemskerk,W. Groen; Underwater noise of Trailing Suction Hopper Dredgers at Maasvlakte2: analysis of source levels and background noise, TNO-DV 2010 C335,November 2010, available at http://www.noordzeeloket.nl/overig/bibliotheek.asp(last accessed 20 February 2012).

The main purpose of this sampling was to study the larvae and eggs in the Dutch EEZ, on a monthly basis

OWEZ project, parts of the Northsea have been visited and seabirds along transects were counted. ESAS database

The main purpose of this sampling was to study the effects on fish near the monopiles in the OWEZ windpark. A multi-mesh gillnet is used, with six mesh sizes. Each mesh size forms a single panel of 6,7 meters in width. Every mesh-size panel occurs twice in each net, thus a complete net consists of 12 panels and has a length of about 80 meters.

A high resolution sonar (DIDSON) was used to record the fish community in the vicinity of the monopiles. It is a good instrument for estimating the abundance of fish around the piles and to study the behaviour fish around the piles, although from the images of the DIDSON it is not possible to identify all fish species.

Movement of individual Seals followed by Telemetry

The survey applies hydroacoustic techniques to get an estimate of the pelagic fish stock community due to the construction of the Offshore Windfarm Egmond aan Zee (OWEZ). The monitoring program comprehends a baseline study (T0) before the construction of the windfarm, one study period a year after its construction (T1) and a monitoring study 5 years afterwards (T5). Temperature and salinity data were collected using Hydrolab datasondes attached to the towed body as well as separate downcasts. The acoustic instrument used is a SIMRAD EK60 echosounder with 38kHz split-beam transducer.