Seal monitoring and evaluation for the Gemini offshore windpark: Pre-construction, T0 - 2014 report

Two species of seals live in Dutch waters: the grey seal (Halichoerus grypus) and the harbour seal (Phoca vitulina). Although hauling out on near-shore tidal sandbanks, both species forage predominantly in the North Sea. Anthropogenic activities within the North Sea have the potential to overlap with the movement and habitat use of the seals, and alter the habitat available to them. The Gemini offshore windpark project represents the fourth windpark development in the Dutch North Sea coastal zone. In the construction permit issued by the Dutch government for Gemini windpark, seal monitoring was requested. The primary aim of seal monitoring was to collect data on habitat use by the seals in the North Sea coastal zone, and investigate if construction and operation of the Gemini windpark influences this habitat use. Results of the monitoring show that although overlap with the windpark appeared strongest for grey seals, it is realised that in the eastern Dutch Wadden Sea, harbour seals greatly outnumber grey seals. Hence, it cannot be determined which species would occur with the greatest prevalence within the windpark

Habitat quality for Grey Seals in the Dutch Wadden Sea

Growth in numbers has seen the Netherlands become a strong-hold for grey seals in continental Europe. This report has the following subjects (questions posed by the Dutch Ministry): “Is a favourable status of the habitat quality of the grey seal in the Netherlands dependant on the presence of undisturbed, permanently dry breeding sites, or do the current sites, which are considered sub optimal, suffice for a long term survival of the species in the Netherlands?” and "How is the growth influenced by immigration from other areas (i.e. the UK)?

Seal monitoring and evaluation for the Luchterduinen offshore wind farm: 2. Tconstruction - 2014 report

Two seal species live in Dutch waters: the harbour seal (Phoca vitulina) and the grey seal (Halichoerus grypus). They occupy land-based sites (haul-outs) in both the Wadden Sea and the Delta region, and move between these regions along the North Sea coastal zone. Human activities, such as construction of a wind farm in this zone, may influence movement and use of the zone by the seals. Monitoring of potential impacts on seals to Luchterduinen construction was required in the permit to construct. The Luchterduinen offshore wind farm is the third wind farm development in the Dutch North Sea coastal zone (between Den Helder and Rotterdam). Pile-driving of the turbine towers occurred between 31 July and 16 October, 2014. Seals exposed to pile-driving, even at close distances o

Seal monitoring and evaluation for the Luchterduinen offshore wind farm 1. T0 - 2013 report

In the Netherlands, the greatest numbers of grey and harbour seals are observed hauling out in the Wadden Sea but both species also haul out in the Delta region. Previous studies suggest there could be considerable movement of seals along the Dutch North Sea coastal zone between the two regions. Next to providing feeding opportunities for the seals, this movement may be particularly important for the maintenance of seal numbers in the Delta, and could be affected by anthropogenic developments in the coastal zone, such as wind farms. Determining when to attach devices to seals must take into account the seals’ annual cycles; in the Netherlands, grey seals give birth in winter and moult in spring, while harbour seals give birth in early summer and moult in late summer. Capturing and tracking of seals is limited by both the pupping period and the moulting period

Use of the East Anglia Offshore windfarm area, UK, by seals tracked from the Netherlands

This report presents data on use by seals tracked from the Netherlands of a zone of the North Sea off the east coast of the UK, the East Anglia Zone, where it is proposed to develop offshore windfarms. For this report, three areas of interest are distinguished within the East Anglia Zone: East Anglia THREE Offshore Windfarm (East Anglia THREE); East Anglia FOUR Offshore Windfarm (East Anglia FOUR) and the combined cable corridor for both projects. In the Netherlands, seals have been tracked from two Natura2000 areas: the Wadden Sea to the north and the Delta region to the south. Approval was sought from current clients of IMARES to incorporate data from seal research they have sponsored. All clients supported sharing of the data. Of 273 harbour seals fitted with trackers in the Netherlands between 1998 and 2013, ten came within 20km of an East Anglia area of interest and seven of those entered an area of interest. Of 77 grey seals fitted with trackers in the Netherlands, six came within 20km of an East Anglia area of interest and four of those entered an area of interest. Of the seals that entered an East Anglia area of interest, all but one probably spent >2% of their time-at-sea within that area. The exception was a harbour seal tracked from the Dutch Delta region (Zeeland) in 2007, which spent at least 2% and up to 17% of its time-at-sea within an area of interest

Majority versus minority dynamics: Phase transition in an interacting two-state spin system

We introduce a simple model of opinion dynamics in which binary-state agents evolve due to the influence of agents in a local neighborhood. In a single update step, a fixed-size group is defined and all agents in the group adopt the state of the local majority with probability p or that of the local minority with probability 1-p. For group size G=3, there is a phase transition at p_c=2/3 in all spatial dimensions. For p>p_c, the global majority quickly predominates, while for p<p_c, the system is driven to a mixed state in which the densities of agents in each state are equal. For p=p_c, the average magnetization (the difference in the density of agents in the two states) is conserved and the system obeys classical voter model dynamics. In one dimension and within a Kirkwood decoupling scheme, the final magnetization in a finite-length system has a non-trivial dependence on the initial magnetization for all p.ne.p_c, in agreement with numerical results. At p_c, the exact 2-spin correlation functions decay algebraically toward the value 1 and the system coarsens as in the classical voter model.Comment: 11 pages, 3 figures, revtex4 2-column format; minor revisions for publication in PR

Influence of gestation housing on sow behavior and fertility

Contains fulltext : 56272.pdf (publisher's version ) (Open Access)Objective: To examine the effect of group housing sows on their behavior and fertility. Materials and methods: In Experiment One, at 65 to 70 days of gestation, 96 sows were assigned by parity to individual or group housing and observed for aggressive encounters during three 1.5-hour time blocks immediately after relocation and 1 day later. On the third day, feeding-time aggression was observed during two 30-minute feeding periods, starting when feed was dropped. Saliva samples obtained from unrestrained sows 1 day before and after relocation were assayed for cortisol concentrations. In Experiment Two, 937 mixed-parity sows in 10 weekly breeding groups were either housed in groups of approximately 50 (n = 462) or individually housed in gestation stalls (n = 475). For 140 individually-housed and 330 group-housed sows, backfat depths at the P2 position were determined using A-mode ultrasonography at gestation days 55 to 60, at farrowing, and at weaning. Results: Group-housed sows were involved in more aggressive encounters than stall-housed animals (P < .05). Aggressive encounters per hour were more numerous in grouped sows during feeding on day 3 than during the day of grouping (P < .001). Salivary cortisol concentrations were higher in grouped sows, but differences between pre-and post-relocation concentrations were not correlated with levels of aggression. There was no effect of housing on backfat depths or sow fertility. Implication: If sows are grouped during gestation, particular attention should be directed toward feeding management to avoid excessive aggression and possible adverse effects on welfare