Grey seals (Halichoerus grypus) in the Dutch North sea: population ecology and effects of wind farms

This study was setup to gain an understanding of the possible effects of large-scale development of wind farms in Dutch waters on grey seals (Halichoerus grypus). This should be considered a first step in doing so as up until now relatively little was known about the species in Dutch waters. The study was carried out in the framework of WE@SEA a foundation aimed at acquiring knowledge in the field of offshore wind energy

Harbour porpoises (Phocoena phocoena) and wind farms: a case study in the Dutch North Sea

The rapid increase in development of offshore wind energy in European waters has raised concern for the possible environmental impacts of wind farms. We studied whether harbour porpoise occurrence has been affected by the presence of the Dutch offshore wind farm Egmond aan Zee. This was done by studying acoustic activity of porpoises in the wind farm and in two reference areas using stationary acoustic monitoring (with T-PODs) prior to construction (baseline: June 2003 to June 2004) and during normal operation of the wind farm (operation: April 2007 to April 2009). The results show a strong seasonal pattern, with more activity recorded during winter months. There was also an overall increase in acoustic activity from baseline to operation, in line with a general increase in porpoise abundance in Dutch waters over the last decade. The acoustic activity was significantly higher inside the wind farm than in the reference areas, indicating that the occurrence of porpoises in this area increased as well. The reasons of this apparent preference for the wind farm area are not clear. Two possible causes are discussed: an increased food availability inside the wind farm (reef effect) and/or the absence of vessels in an otherwise heavily trafficked part of the North Sea (sheltering effect

Rapid recovery of Dutch gray seal colonies fuelled by immigration

Gray seals were first observed breeding in the Dutch Wadden Sea in 1985, after centuries of absence. The breeding colony there is now the largest on the European continent. We describe the changes in gray seal numbers and their geographical expansion, and estimate how these processes were influenced by immigration from other colonies. Counts of hauled out animals were carried out between 1985 and 2013, monitoring three different periods of the seals’ annual cycle. Using priors determined for the UK population, a Bayesian demographic model was fitted to pup numbers to estimate the population parameters driving the growth. This included immigration of sub-adults into the breeding population, which contributed to an average growth rate in the pup counts of 19%/y, much higher than expected in a closed population. This immigration may account for approximately 35% of the total annual growth. In addition, at least 200 grey seals from the UK visit the area temporarily. Recovery of the population in the Netherlands occurred more than 50 yr after gray seals were protected in the UK. These time scales should be taken into account when studying long living marine mammals, e.g. in impact and conservation studies

Data availibility for the fisheries impact assessment of the FIMPAS project

The project Fisheries Measures in Protected Areas (FIMPAS) aims to introduce fisheries measures in the marine Natura 2000 sites within the Exclusive Economic Zone of the Dutch part of the North Sea by the end of 2011. The FIMPAS project covers three such areas, the Dogger Bank and the Cleaver Bank (both to be designated for protection under the Habitats Directive) and the Frisian Front (to be designated for protection under the Birds Directive). These sites are beyond the Dutch 12 nm zone and several EU Member States fish within these areas. Therefore fisheries measures must be implemented through the Common Fisheries Policy. These marine protected areas, as well as the potential fisheries measures, are a consequence of the implementation of the European Birds and Habitats Directives and will be proposed to the European Commission by the Dutch government. The Dutch Ministry for Agriculture, Nature and Food Quality (LNV), together with Dutch environmental NGOs and the Dutch fishing industry, are cooperating within the FIMPAS project to develop the necessary fisheries measures to achieve the conservation objectives for the Dutch Natura 2000 sites of the North Sea. LNV has asked the International Council for the Exploration of the Sea (ICES) to organize the necessary scientific processes and give advice on the desired fisheries measures involving the relevant stakeholders in this process

Zeezoogdieren in de Eems Evaluatie van de Vliegtuigtellingen van zeezoogdieren tussen oktober 2007 en september 2008

Groningen Seaports heeft de ambitie om de Eemshaven te ontwikkelen tot een belangrijk energiecentrum onder de naam "Energy Park Eemshaven". Bovendien worden de Eemshaven en de vaargeul naar de Noordzee verruimd en verdiept. Er komen drie soorten zeezoogdieren in het gebied voor. De meest algemene soort is de gewone zeehond, Phoca vitulina; ook worden er grijze zeehonden Halichoerus grypus en bruinvissen Phocoena phocoena in het gebied gezien. In Brasseur (2007) worden leemtes in de beschikbare kennis van de grijze zeehond en de bruinvis geconstateerd, en tevens over de winterverspreiding van de gewone zeehond. Aangezien de ontbrekende kennis noodzakelijk is om te komen tot een gedegen afweging van de mogelijke effecten van de geplande activiteiten wordt verder onderzoek aanbevolen naar: A. De ruimtelijke en temporele spreiding van de drie soorten in het gebied; B. Migratiegedrag van de drie soorten; C. Voor de zeezoogdieren frequentiespecifieke geluidscontouren van de bouwactiviteiten – met en zonder mitigatie

Assessment of the Effects of the Offshore wind Farm Egmond aan Zee (OWEZ) for Harbour Porpoise (comparison T0 and T1)

The aim of this study was to investigate whether the Offshore Wind farm Egmond aan Zee (OWEZ) has influenced the occurrence of harbour porpoises

Setback distances as a conservation tool in wildlife-human interactions : testing their efficacy for birds affected by vehicles on open-coast sandy beaches

In some wilderness areas, wildlife encounter vehicles disrupt their behaviour and habitat use. Changing driver behaviour has been proposed where bans on vehicle use are politically unpalatable, but the efficacy of vehicle setbacks and reduced speeds remains largely untested. We characterised bird-vehicle encounters in terms of driver behaviour and the disturbance caused to birds, and tested whether spatial buffers or lower speeds reduced bird escape responses on open beaches. Focal observations showed that: i) most drivers did not create sizeable buffers between their vehicles and birds; ii) bird disturbance was frequent; and iii) predictors of probability of flushing (escape) were setback distance and vehicle type (buses flushed birds at higher rates than cars). Experiments demonstrated that substantial reductions in bird escape responses required buffers to be wide (> 25 m) and vehicle speeds to be slow (< 30 km h-1). Setback distances can reduce impacts on wildlife, provided that they are carefully designed and derived from empirical evidence. No speed or distance combination we tested, however, eliminated bird responses. Thus, while buffers reduce response rates, they are likely to be much less effective than vehicle-free zones (i.e. beach closures), and rely on changes to current driver behaviou

Setback distances as a conservation tool in wildlife-human interactions : testing their efficacy for birds affected by vehicles on open-coast sandy beaches

In some wilderness areas, wildlife encounter vehicles disrupt their behaviour and habitat use. Changing driver behaviour has been proposed where bans on vehicle use are politically unpalatable, but the efficacy of vehicle setbacks and reduced speeds remains largely untested. We characterised bird-vehicle encounters in terms of driver behaviour and the disturbance caused to birds, and tested whether spatial buffers or lower speeds reduced bird escape responses on open beaches. Focal observations showed that: i) most drivers did not create sizeable buffers between their vehicles and birds; ii) bird disturbance was frequent; and iii) predictors of probability of flushing (escape) were setback distance and vehicle type (buses flushed birds at higher rates than cars). Experiments demonstrated that substantial reductions in bird escape responses required buffers to be wide (> 25 m) and vehicle speeds to be slow (< 30 km h-1). Setback distances can reduce impacts on wildlife, provided that they are carefully designed and derived from empirical evidence. No speed or distance combination we tested, however, eliminated bird responses. Thus, while buffers reduce response rates, they are likely to be much less effective than vehicle-free zones (i.e. beach closures), and rely on changes to current driver behaviou

Zeezoogdieren op de Noordzee : achtergronddocument bij Natuurverkenning 2011

Dit werkdocument bevat een beknopte synthese van de kennis over ecologie, verspreiding en de aantalsontwikkeling op het Nederlands Continentaal Plat (NCP) van gewone en grijze zeehond en vier inheemse walvisachtigen: bruinvis, dwergvinvis, witsnuitdolfijn en tuimelaar. Aan de hand van kennis over het voorkomen in het verleden, aantalsveranderingen, ecologie, bedreigingen en correlaties met omgevingsfactoren en verwachte ontwikkelingen hierin wordt een grof toekomstbeeld van het voorkomen van de besproken zeezoogdieren geschetst