MinisterHenk Kamp

Ministerie van Economische Zaken

Bezuidenhoutseweg 73

2594 AC Den Haag

The Netherlands

Chippenham, 21st August 2014

Honourable Minister Henk Kamp,

We have recently learned about the seismic survey that is currently taking place in Dutch waters, close to the German border. As organisations dealing with cetacean protection, we are extremely concerned about this survey for various reasons including:

It is well known that high intensity sounds, such as those produced by airguns, can disturb, distress, or physically injure cetaceans, often with lethal consequences;

The area where the survey takes place is a known habitat for the harbour porpoise, a species strictly protected under the EU Habitats Directive (HD);

Summertime is known as the most sensitive period for harbour porpoises, as they give birth to their young, which are especially vulnerable to anthropogenic sound;

A Special Area of Conservation (SAC) for harbour porpoises exists next to the survey area, on the German side.

We express our grave concern about the ongoing seismic survey and note importantly that neither a proper Environmental Impact Assessment with public participation has been undertaken, nor the neighbouring country whose waters are affected has been involved in the decision-making or even consulted. The provisions of the EU Habitat Directive do not allow the deliberate disturbance of protected species, therefore EU environmental law is breached with every day this survey continues. We strongly urge you to take all necessary steps to immediately stop the survey and withdraw all issued licences – until all necessary proper steps have been taken.

We look forward to hearing from you and would like to provide the following comments below to substantiate our views and concerns.

Yours sincerely,

Vanesa Tossenberger / Sigrid Lüber
Policy Director, Whale and Dolphin Conservation / President, Ocean Care


The output of air gun arrays is usually designed to produce a concentration of low-frequency energy, but the impulsive nature of the bubble collapse inevitably results in a broadband sound characteristic. In general, source levels at the low-frequency end of the spectrum are high, between 220 – 255 dB re 1 μPa @ 1 m (Richardson et al., 1995; Parsons et al., 2003). Although the direction of greatest sound intensity is downwards, a considerable amount of energy is radiated in directions away from the beam axis (McCauley, 1994 as cited in Parsons et al., 2003, Goold & Fish, 1998). This refers especially to higher frequencies.

Seismic airguns produce predominantly low frequency sounds, but it has been shown that high frequency noise is also produced. Goold & Fish (1998) found significant levels of energy across the recorded bandwidth up to 22 kHz. This high frequency sound, incidental to seismic operations, will overlap with the frequencies used by toothed whales, and could potentially cause disturbance to harbour porpoise. Observations made by Goold (1996) suggest an avoidance reaction of dolphins to air gun emissions. At 500 – 800 Hz, Richardson et al. (1995) expected components of the seismic sounds from a ship to exceed both the typical ambient noise levels and the absolute auditory threshold of harbour porpoises as far as 100 km away.


We would also like to note that apart from consequences to marine mammals, there are wider effects on the marine environment that have to be taken into account.

Fisheries: Three decades of controlled scientific studies leave no doubt that intense sound damages fish and impacts fisheries. Several studies show that fish catch rates are significantly lowered by noise from air guns indicating that increasing levels of human-produced noise in the ocean can significantly and adversely impact the food supply, employment and economies of many nations. As an example, in a study by the Norwegian Institute of Marine Research, air guns caused extensive damage to the inner ears of fish and lowered trawl catch rates 45 to 70% over a 2,000 square mile area of ocean. Catch rates did not recover in the five days surveyed after air gun use stopped (Engås et al., 1996). Air gun pulses also caused a catch per unit effort decline of about 50% in the rockfish hook and line fishery off the coast of California. The UN General Assembly on sustainable fisheries has called upon the FAO to carry out studies on the socio-economic impacts of ocean noise pollution on fisheries – namely OP153 of doc A/RES/68/71 which reads as follows: "Encourages further studies, including by the Food and AgricultureOrganization of the United Nations, on the impacts of underwater noise on fish stocks and fishing catch rates, as well as associated socioeconomic effects". The need for such studies should not be underestimated. The use of air guns near fish stocks severely affects their distribution, local abundance as well as trawl and long-line catch rates. In this context it might be important that herring, an important component of harbour porpoise diet in the North Sea, is known to have special auditory capabilities (e.g. Engeret al., 1993, Culiket al., 2001). Loud noise over extended periods could cause temporary dispersion of aggregations of fish, resulting in a loss to the harbour porpoise, and/or higher energy demands associated with foraging activities.

Fish, crustaceans and cephalopods: Behavioural responses of fish to seismic noise is varied and include leaving the area of the noise, changes in depth distribution, spatial changes in schooling behaviour, as well as startled responses to short range start-up or high level sounds.In some cases behavioural responses were observed up to 5 km distance from the seismic air gun array. Recent research by Fewtrell and McCauley (2012) indicate a clear behavioural response to air gun noise levels. As these increase, fish respond by moving to the bottom of the water column and swimming faster in more tightly cohesive groups. Significant increases in alarm responses were observed in fish and squid to air gun noise above 147–151 dB (re 1µPa2.s SEL). An increase in the occurrence of alarm responses was also observed as the noise level increased. A later study showed a strong likelihood of damage to the ears of some fish. Such impacts could have significant implications for the behaviour and fitness of populations of fish species. Although the effects of air gun noise on the spawning behaviour of fish have not been quantified to date, researchers believe that if fish are exposed to powerful external forces on their migration paths or spawning grounds, they may be disturbed or even cease spawning altogether.

Similar studies have produced comparable results for cephalopods (octopuses, squid, cuttlefish and Nautiloidea) and crustaceans in a number of parts of the world. Such effects on species located lower in the food chain can easily have effects on top predators such as harbour porpoises, as long as prey species are affected.

Disruption of behaviour during critical periods such as mating, spawning and migration could be particularly important. However, the significant absence of studies before, during and after surveys means that empirical evidence is hard to demonstrate. The absence of studies is mostly because the industry has been reluctant to fund or facilitate the studies. However, the absence of evidence is not evidence of absence. Seismic survey proponents cannot empirically demonstrate that their activities cause no harm.


All cetaceans are offered strict species protection under Article 12 of the EU Habitats Directive, where the harbour porpoise is listed as an Annex II. Particular obligations apply to the habitats of Annex II cetaceans under Article 6(2). This provision prescribes a two-pronged approach to habitat protection, with Member States to “take appropriate steps to avoid, in the Special Areas of Conservation, the deterioration of natural habitats and the habitats of species as well as disturbance of the species for which the areas have been designated, in so far as such disturbance could be significant in relation to the objectives of the Directive”.

Harbour porpoises are seemingly wide ranging throughout the year in Dutch waters, with locally varying densities throughout the Southern Bight. Clusters of sightings may occur in certain areas, with hydrographical characteristics locally (and temporally) enhancing the foraging conditions (e.g. frontal systems), but these are seemingly short-lived and/or of seasonal importance only (CamphuysenSiemensma 2011). Nonetheless, The Netherlands, in recognising their role in contributing to a coherent network, has designated four SACs with the harbour porpoise as a B grade.

In order to effectively protect cetaceans from in-combination and cumulative threats, and meet the requirements of the EU Habitats Directive, including favourable conservation status (FCS), and Good Environmental Status (GES) under the MSFD, a combination of both spatial management and wider management is required. Action must be taken to meet the Directive’s requirements to ensure the favourable conservation status of populations of some cetaceans outside designated SACs as well as within them, and this will be predicated on having adequate data to be able to show this. At the most basic level, baseline monitoring for the marine species found in the areas of interest should be undertaken to allow for informed decision making. We are of the opinion that a priority must be the establishment of an effective long-term continuous research and monitoring program to address the deficiencies in our knowledge with regards to characteristics and effects of seismic survey operations and mitigation methods.

Directly neighbouring the survey area, in German waters, the Borkum Reef Ground has been declared a SAC under the HD because it hosts a rich diversity of fauna species in a relatively small area. The many different ecological communities come together in a great mosaic of biodiversity. One of the site’s main functions is revealed in conjunction with the tides: It is an important stepping stone for the spread of species across the southern North Sea. Habitats Directive Annex II species found here are harbour porpoises, grey seals and common seals. These are consequently included in the conservation objectives. Harbour porpoises are spotted with low average frequency but on an ongoing basis, sometimes with calves. They are thought to be part of the fairly small, endangered subpopulation of the southern North Sea whose distribution centre is off the Dutch coast. The conservation objectives of this SAC include the maintenance and restoration at favourable conservation status of the following Habitats Directive species and their natural habitats: harbour porpoise, common seal, grey seal and twait shad. (see


We note that an Environmental Impact Assessment (EIA) with public participation has not been undertaken. Such requirements have also been adopted within the revision of the Environmental Impact Assessment Directive of the European Union in spring 2014.

Around the world, offshore petroleum exploration proposals are presented to Governments with generalized, unsubstantiated information and often without having conducted basic consultation. Because often the expectation from Governments has not been carefully prescribed – by failing to specify the detail of technical and substantiated information that will be required – the EIAs that are submitted are often poorly developed or provide a limited explanation about the source of data or the level of uncertainty inherent in the documentation. Subsequent decision-maker approvals of these EIAs are being made on the basis of erroneous information and are vulnerable to criticism of bias or tokenism.

As an example, modelling should provide a clear indication of sound dispersal characteristics in the same seasonal conditions as the proposed survey. This should factor local propagation features (spherical and cylindrical spreading, depth and type of sea bottom, local propagation paths related to thermal stratification), and out to a radius of a thousand nautical miles. The modelling should identify any Sound Fixing and Ranging Channels (SOFAR) or other natural characteristics that are of importance for propagation. With this information it should be possible to identify proposed species exclusion zones and descriptions of how noise propagation into these zones will be minimized, taking into consideration the local propagation features (spherical and cylindrical spreading, depth and type of sea bottom, local propagation paths related to thermal stratification). Only with this level of technical information can a realistic Environmental Impact Assessments be produced.

We would like to know if such modelling efforts were carried out well before the survey and if the results have been presented to the Dutch Government.

Generally, the EU SEA and EIA Directive should be applied and we should strongly request that all Member States apply Strategic Environmental Assessments (SEA) to oil and gas activities at a national level and that oil and gas activities, including seismic surveys should be subjected to individual developers’SEA including a transparent public consultation. Hence, we would like to know if an SEA has been conducted. A common request for both EIA and SEA are consultations of neighbouring countries whose waters will be affected. In this case, this is clearly true for German waters (see above), if not other EU members, too (due to the potentially very large range of the underwater noise produced by airguns).

We learned from the German Environmental Ministry (BMUB), that they were not consulted prior to the survey. If this is correct, what was the reason?


Management: Requirements to reduce the impact of acoustic disturbance from offshore seismic surveys on the management level always have to include:

reducing the amount of sound entering the environment which can be done through the appropriate choice of equipment and survey design;

avoiding times in which the survey area and surroundings are supporting biologically significant activities such as breeding, feeding or migrating species through the use of temporal zonation;

ensuring, where possible, that protected species in the survey area and surrounding environment are not exposed to levels of sound which can cause physical damage; and

to continually collect information on how this process can be improved and to review and improve the process as new information, processes and technology emerge.

These are strong foundations upon which to develop robust and effective monitoring and mitigation plans.

Mitigation: WDC fully supports the implementation of a shut-down of the seismic source whenever an individual of any species comes within the mitigation radius where injury may occur. The use of and reporting from Marine Mammal Observers (MMOs) and Passive Acoustic Monitoring (PAM) throughout active shooting will enable a solid dataset of species and potential impacts to be collected. It is worth considering producing a template report format for MMOs to use, to enable standardised collection including all data required, as well as maps of survey areas covered. Details of mitigation requirements should be reported and available for all seismic surveys undertaken in Dutch and European waters. Standard management guidance generally only deals with localised injury impacts that may occur in close range to the source to approximately 500 metres away. Behavioural and wider disturbance impacts can be expected at greater distances that are not observable from on-board a seismic vessel. For example, the JNCC seismic guidelines, which have been referred to by Hansa Hydrocarbons, do not deal with disturbance impacts. Monitoring and mitigation measures to assess impacts beyond injury are a serious flaw in existing guidelines.

Alternative technology: Seismic airguns generate a great deal of waste noise (anything over 100 Hz up to as high as tens of kHz) that is unused by the oil and gas industry or geophysical researchers. They also produce a loud pulse that is damaging to marine life because it is so sharp (with a fast rise time). More environmentally benign alternatives exist (see Weilgart, 2012), such as Marine Vibroseis, which can be over 1,000 times quieter without the sharp rise time and without any of the wasted sound. In some environments, it even outperforms airguns in collecting geophysical data.


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