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Review

A critique of the UK’s JNCC seismic survey guidelines for minimising acousticdisturbance to marine mammals: Best practise?

E.C.M. Parsons a,b,*, Sarah J. Dolman c,d, Michael Jasny e, Naomi A. Rose f, Mark P. Simmonds c,Andrew J. Wright g

a Department of Environmental Science and Policy, George Mason University, 4400 University Drive, Fairfax, Virginia 22030, USAb University Marine Biological Station Millport (University of London), Cumbrae KA28 0EG, Scotland, UKc Whale and Dolphin Conservation Society, Brookfield House, 38 St. Paul St., Chippenham, Wiltshire, SN15 1LJ, UKd School of Biological Sciences, Zoology Building, Tillydrone Avenue, University of Aberdeen, Aberdeen AB24 2TZ, Scotland, UKe Natural Resources Defense Council (NRDC), 1403 Second Street, Santa Monica, California, 90403, USAf Humane Society International, 2100 L Street, NW, Washington, DC, USAg Leviathan Sciences, 3414 17th St. N, Apt. 3, Arlington, Virginia 22207, USA

a r t i c l e i n f o

This paper is significantly the product ofdiscussions over the last decade with manyexperts working within the industry andmany concerned scientists. These people areregrettably too numerous to name.However, we would like to dedicate thispaper to the memory of one suchexceptional person: Wolfgang Dinter, apioneer in the marine acoustics field, whoseinsights, integrity, energy and enthusiasminspired us and many others, and who issadly missed.

Keywords:CetaceanSeismic surveysOil and gas industryMitigation measuresUnderwater noiseConservation

a b s t r a c t

The United Kingdom’s statutory conservation agency, the Joint Nature Conservation Committee (JNCC),developed guidelines in 1995 to minimise acoustic disturbance of marine mammals by oil and gas indus-try seismic surveys. These were the first national guidelines to be developed and have subsequentlybecome the standard, or basis, of international mitigation measures for noise pollution during seismicsurveys. However, relatively few aspects of these measures have a firm scientific basis or proven efficacy.Existing guidelines do not offer adequate protection to marine mammals, given the complex propagationof airgun pulses; the difficulty of monitoring in particular the smaller, cryptic, and/or deep-diving species,such as beaked whales and porpoises; limitations in monitoring requirements; lack of baseline data; andother biological and acoustical complications or unknowns. Current guidelines offer a ‘common sense’approach to noise mitigation, but in light of recent research and ongoing concerns, they should beupdated, with broader measures needed to ensure adequate species protection and to address data gaps.

� 2009 Elsevier Ltd. All rights reserved.

1. Introduction

Cetaceans depend upon sound to navigate the ocean, find prey,avoid predators and communicate with conspecifics. As their pri-mary sense, hearing is of considerable importance to these ani-mals. Concerns surrounding the potential impacts ofanthropogenic marine noise pollution on cetaceans arose primarilythrough a number of ‘key’ events (see Parsons et al. (2008);Weilgart (2007) for more details), including the Acoustic Thermom-etry of Ocean Climate research programme (ATOC),1 a controversialoceanic experiment which involved high intensity sound sources

which partly prompted a subsequent National Research Council spe-cial meeting on underwater sound (National Research Council,1994); and a number of mass strandings of beaked whales (in 1985,1988 and 1989) in the Canary Islands coincident with military activi-ties (Simmonds and Lopez-Jurado, 1991). In February 1995, in order tohelp meet an international obligation under the Agreement on theConservation of Small Cetaceans in the Baltic and North Seas (ASCO-BANS), the Department of the Environment published the Guidelinesfor minimising acoustic disturbance to small cetaceans, aimed primarilyat reducing such disturbance from seismic surveys (Stone, 1997).

These guidelines, developed by the United Kingdom’s statutoryconservation agency, the Joint Nature Conservation Committee(JNCC), specifically were intended to minimise acoustic disturbanceof marine mammals by oil and gas industry seismic surveys (Stone,1997), which involve the production of high intensity sound todetermine the geological characteristics of strata underlying theseabed. These guidelines were the first national guidelines to be

0025-326X/$ - see front matter � 2009 Elsevier Ltd. All rights reserved.doi:10.1016/j.marpolbul.2009.02.024

* Corresponding author. Address: Department of Environmental Science andPolicy, George Mason University, 4400 University Drive, Fairfax, Virginia 22030,USA. Tel.: +1 301 977 7109.

E-mail address: ecm-parsons@earthlink.net (E.C.M. Parsons).1 ATOC was active between 1995 and 2000. The project was effectively resurrected

in 2002, at least in part, under as the North Pacific Acoustic Laboratory (NPAL) project.

Marine Pollution Bulletin 58 (2009) 643–651

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developed for seismic surveys and have subsequently become thestandard, or basis, of international mitigation measures for noisepollution during seismic surveys (see below).

The JNCC guidelines are broken down into sections. Section 2 ofthe guidelines introduces general precautions to reduce distur-bance in the planning phase and during operation of a seismic sur-vey. Section 3 offers guidance for carrying out the ‘soft-start’ – aslow increase in the source level of seismic blasting over a periodof 20 min which is intended to allow marine mammals time tovacate the ensonified area before the seismic surveys operate at fullnoise level (also know as a ‘ramp-up’). Section 4 details the require-ments of the marine mammal observers (MMOs), trained individu-als whose responsibility it is to conduct dedicated observationsaround the vessel during components of the survey, before thecommencement of firing the seismic airguns. Section 5 covers theacoustic monitoring requirements for some regions. Sections 6and 7 provide background information and relevant contact details.

The JNCC maintains responsibility for the guidelines and, underthe guidelines, operators are required to consult with the JNCC whenplanning a seismic survey (including site surveys) in UK waters(Stone, 1997). After one year of use, the guidelines were revised in1996. In 1998 and 2000, the JNCC revised its guidelines again,including expanding them to cover all cetaceans (Stone, 2000).

JNCC guidance became statutory in 2001 with the transpositionof the European Union (EU) Habitats and Species Directive (92/43/EEC) into national law. This occurred for all oil and gas activities inthe UK Continental Shelf (UKCS) through the Offshore PetroleumActivities (Conservation of Habitats) Regulations. Despite being re-ferred to as ‘guidelines’, the JNCC measures are thus now a legisla-tive requirement. As part of these regulations any companywishing to carry out a seismic survey in the UKCS must apply forconsent from the UK government’s Department of Energy and Cli-mate Change (DECC), previously Department for Business and Reg-ulatory Reform (BERR). An end of survey report, detailing specificinformation about the survey including the size of the airguns, re-cord of airgun use and species encountered, is a further require-ment (JNCC, 2004). The JNCC has produced summarised reportsof the data collected (Stone, 1997, 1998, 2000, 2003a,b,c, 2006).

However, relatively few aspects of current guidelines or seismicsurvey mitigation methods have a firm scientific basis or proven effi-cacy (Weir and Dolman, 2007). In the British government’s ownwords, ‘‘. . .current mitigation [of seismic surveys] is largely based on‘common sense’ measure[s] and it is difficult to establish whether theywork and/or could be made more effective” (p. 156, Department ofTrade and Industry, 2002). The main weakness is inadequate plan-ning, which includes a lack of sufficient data upon which to basedecisions. Furthermore, inadequate account is currently being takenof science available to determine the range of impacts.

Mitigation measures currently in place may, in some cases, re-duce some of the acute impacts of marine noise pollution. But theydo not mitigate against the chronic degradation of habitat causedby repeated use of this far-travelling and high-intensity noise. Nei-ther do they meet the requirements of the EU Habitats Directive.2

Current guidelines and mitigation standards also do not take into ac-count cumulative exposures or synergistic effects with other factors,such as exposure to contaminants, as required under this precau-tionary environmental legislation.3 Other important issues discussedin this paper include the use of marine mammal observers; the lim-

itations of the requirement for passive acoustic monitoring; and thelack of consideration in the current guidelines of environmental fac-tors, such as oceanographic effects, and of compliance andenforcement.

The consequences of these flawed guidelines extend well be-yond British waters. Australia’s Department of Environment andHeritage (formerly Environment Australia) developed seismicguidelines in 2001 and revised these in 2008. In recent years,guidelines have also been developed in locations such as Alaska,Brazil, California, Canada, New Zealand, the Gulf of Mexico andSakhalin, Russia (for an introduction to seismic surveys and a com-prehensive review of guidance, see Weir and Dolman, 2007).Although varying considerably in the details, many of these arebased on the JNCC guidelines (see Weir and Dolman, 2007). Suchguidelines have become a widely accepted approach to resolvingthe problem of the various effects of noise pollution during seismicsurveys.

This reliance on the JNCC guidelines by other countries is argu-ably premature. This paper outlines some of the major flaws withcurrent JNCC guidance. With more countries introducing seismicguidance based on the JNCC’s guidelines (Weir and Dolman,2007) it is important that the flaws noted in the following critiqueare not perpetuated. It is also important that these flawed guide-lines do not become standard in other industries as well. For exam-ple, the JNCC is now developing guidance for pile-driving andexplosive use, as part of broader guidance being aimed at prevent-ing deliberate and significant4 disturbance to marine European Pro-tected Species, as required under the EU Habitats Directive, and isthought to be basing these on the current seismic survey guidelines.This paper makes suggestions for rectifying the flaws with the aim ofmeeting legal European requirements and, ultimately, better pro-tecting cetaceans from the impacts of noise pollution generated asa result of seismic surveys.

2. Planning

2.1. Baseline data gaps

A lack of scientific basis for the JNCC guidelines is well demon-strated in the planning stages. The guidelines suggest that survey-ors examine existing literature to determine if marine mammalsare likely to be present in a region in preparation for seismic activ-ity. However, there are many areas within the UK’s Exclusive Eco-nomic Zone where cetacean survey data are scant or non-existent,as is the case in many regions around the world. The InternationalUnion for Conservation of Nature (IUCN) Red List classifies a num-ber of marine mammal species as endangered, vulnerable, nearthreatened, least concern or data deficient, and this is generallyat a global level. Roughly half of all the cetacean species listed byIUCN are currently categorised as ‘data deficient’ including manyspecies of cetacean that are known to be sensitive to sound (e.g.,beaked whales; Cox et al., 2006). No guidance is provided by theJNCC about what to do where relevant data do not exist or areinadequate. No recommendations to gather data in a standardisedand scientifically valid way are made. In terrestrial surveys, partieswishing to prospect or otherwise develop an area would typicallybe required to undertake surveys to determine habitat use at aminimum, and potentially population size and trends of the spe-cies under investigation, in order to obtain planning approval. Mar-ine planning currently lags many decades behind terrestrialplanning and decisions are being made based on information that

2 For example, ‘‘Member States shall prohibit the use of all indiscriminate meanscapable of causing local disappearance of, or serious disturbance to, populations of[cetaceans]” (92/43/EEC; Article 15).

3 For example, member nations are obligated to maintain or restore species to afavourable conservation status (article 2) with the Directive stating that ‘‘conserva-tion status of a species means the sum of the influences acting on the speciesconcerned that may affect the long-term distribution and abundance of its popula-tions” (92/43/EEC; Article 15).

4 The JNCC consultation on guidance relating to the offence of deliberatedisturbance of marine European Protected Species ended in June 2008 and guidanceis expected in early 2009.

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is insufficient to allow safe development by ensuring adequate pro-tection of marine species.

2.2. Legal obligations

Unlike permitting processes found in some other countries’statutes, such as the US Endangered Species Act (ESA) and the USMarine Mammal Protection Act (MMPA), UK environmental guid-ance has been weak until the introduction of the EU Habitats Direc-tive. Only since the transposition of the EU Directive into UKnational law have the JNCC guidelines had a requirement to assessthe proportion of cetaceans in a management group or populationthat is likely to be injured, disturbed or otherwise adversely af-fected by the requested action. Recent consultations occurred inthe UK (but not Scotland) to fulfil the EU Habitats Directiverequirement to consider the biological ‘significance’ of distur-bance.5 The government has not stated how ‘significance’ will bedetermined without reasonable basic population status data.

Currently, the only general protective measure suggested in theJNCC guidelines is that surveys should be timed to avoid breedingor calving periods. This is not easily done for marine species andcertainly not for species where basic biological information is notavailable. Yet the UK government, like other European countries,has environmental responsibilities under the EU Habitats Direc-tive, and more recently the EU Marine Strategy Framework Direc-

tive, to monitor and maintain its cetacean species. This mandateneeds to be met by European governments with some urgency,both through adequate funding and action, including with ongoingand regular monitoring to determine distribution and populationtrends. Also, science-based recommendations for planning the sit-ing of mitigated activities do exist (Agardy et al., 2007; Wintle,2007).

The JNCC should require a more rigorous and, most importantly,adaptive strategy for planning seismic survey activities. As activi-ties are conducted, observations of species distribution, as wellas any effects of surveys on the animals, should be incorporatedinto plans. This can only be done with a serious commitment toa robust monitoring regime. An example of an adaptive manage-ment process that could be utilised to improve the efficacy of mit-igation, while also conforming with mandates noted above, isillustrated in Fig. 1.

3. Zone of impact

Depending on the arbitrarily predetermined sensitivity of theregion of interest, the JNCC guidelines require that an observer(s)should visually search the waters surrounding the sound sourcefor 30 min prior to the commencement of a seismic survey. Afterthis period there is the ‘soft start’ or ‘ramp-up’ of the seismic array,where the sound of firing guns are introduced over time so that, inprinciple, any animal in the vicinity has the opportunity to leavethe area before sound levels become too high (see the discussionof the ‘soft start’ mitigation method below). During ramp-up, if amarine mammal is seen within 500 m of the centre of the airgunarray, the JNCC guidelines specify that the firing must be delayeduntil the marine mammal has moved away. This 500 m is the pre-sumed zone within which cetaceans would be impacted by seismicnoise.

Existing Information

Planning –suitable spatio-temporal siting of seismic activity

Precaution –required where appropriate data do not exist

Data Collection –commitment to collect lacking baseline data

Survey Plan –in suitable sites with real-time

mitigation and monitoring

Data on Recent Data on Distribution, Abundance

Implementation –responsible seismic operation in selected location

Monitoring –real-time monitoring of impacts of mitigated seismic activity

Operation –activity proceedsInformation on Mitigated

Impact

Mitigation Plan –technical and operational measures to

reduce local impacts

Fig. 1. A proposed structure for adaptive management in seismic survey operations.

5 It is now an offence (in regulation 39(1)(b) of both Amendments to theConservation (Natural Habitats & c). Regulations 1994 and the new Offshore MarineConservation (Natural Habitats, & c). Regulations 2007) to deliberately disturb anEuropean Protected Species (EPS) in such a way as to be likely significantly to affect:a) the ability of any significant group of animals of that species to survive, breed, orrear or nurture their young; or b) the local distribution or abundance of that species.‘Significant’ has yet to be defined by the JNCC. Disturbance of UK cetaceans is alsoaddressed by the Wildlife and Countryside Act.

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It may be that the 500 m zone of impact is an arbitrary figure,given that it is a relatively round number. Alternatively, it mayhave been calculated using models based on hearing abilities andthresholds of captive animals. There are various drawbacks tousing results of captive studies (see for example, Parsons et al.,2008). Perhaps most importantly, studies have shown that free-ranging animals can react at received levels lower than predictedfrom captive studies (e.g., Findley et al., 1990; Koschinski et al.,2003). One study noted that wild dolphins showed aversive behav-iour during exploratory surveys at received levels 10,000 timesquieter than predicted by studies on captive animals (Gould andFish, 1998).

Recent studies examining airgun noise received by taggedwhales have revised our understanding of sound transmission inthe ocean. The received sound levels did not match the computerpredictions. Sound levels decreased between 5 km and 9 km fromthe sound source, but then increased at distances between 9 kmand 13 km (Madsen et al., 2006). The researchers stated that re-ceived levels ‘‘can be just as high at 12 km as they are at 2 km. . .[andcan be detected] well beyond ranges predicted by [computer model-ling] and beyond where visual observers on the source vessel canmonitor effectively” (Madsen et al., 2006). Gould and Coates(2006) demonstrated that the airgun acoustical output covers theentire frequency range known to be used by both cetaceans andpinnipeds, and does so at substantial energy levels. This study sup-ports the findings of Madsen et al. (2006), in which airgun pulsesreceived by sperm whales, Physeter macrocephalus, contained sub-stantive energy between 0.3 and 3 kHz, a frequency range well be-yond the normal frequencies of interest in seismic exploration, butfrequencies that coincide with the hearing capabilities of manytoothed cetaceans. DeRuiter et al. (2006) illustrated that, in manycases, airgun received levels will not decrease monotonically withincreasing range, so that a simple spreading law will not accuratelypredict the observed pattern of received levels at increasing dis-tances from the sound source.

Regulations defining allowable ranges (stand-off distances) be-tween airgun array sound sources and marine species must takeinto account the potentially complicated relationship betweensource-receiver range and depth, acoustic frequency, and receivedsound level (DeRuiter et al., 2006). It follows then that animals mayexperience increased exposure levels as they swim away from asource under some conditions, and decreased levels as they ap-proach. In this case, an animal seeking to reduce exposure in theshort-term may actually approach the source (DeRuiter et al.,2006). Bearing all this in mind, zones of disturbance should bebased on observations of free-ranging, and in most cases also naïve,animals. Whilst the zone of visual observation around the source ismeant to prevent injuries that may occur to animals that travelvery close to the source, it is clear that the visual zone cannot pro-tect animals from disturbance at larger distances.

Regardless of the distances involved, it should also be noted thatthere is no evidence to support or refute the ‘common sense’ suppo-sition that marine mammals swim away from the source; no stud-ies to date have investigated this systematically. Acoustic ‘shadows’(as described above) may actually lead to an animal approachingthe survey vessel. Alternatively, animals may ignore or toleratethe increasing airgun noise, perhaps to remain in a food-rich area.Studies in other (non-cetacean) species have found that hungry ani-mals may remain in an area despite disturbance, acoustic or other-wise (Beale and Monaghan, 2004; see also review in Beale, 2007).This behavioural habituation and/or physiological acclimationcould lead to the animals remaining physiologically non-responsiveuntil, perhaps, exposures reach potentially dangerous levels (seeWright et al., 2007a,b). There is a clear and urgent need for regula-tory agencies such as the JNCC to investigate the ‘common sense’supposition that marine mammals swim away from the source.

Seismic surveys can have an extended range of acoustic impact,in both space and time. Thus, a considerable flaw in the JNCCguidelines is the mismatch between the relatively small areasmonitored for animals (acoustically and/or visually) and the con-siderable area of impact. Seismic survey noise was reported to havebeen detected over 3000 miles from its source and, even at this dis-tance, it masked whale sounds of interest to researchers (Nieukirket al., 2004). Clark and Gagnon (2006) observed that fin whales inthe vicinity of seismic surveys cease vocalizing over large spatialscales, on the order of 10,000 nm2 or greater. Researchers also sug-gested that non-resident, transient or more mobile cetacean spe-cies in Brazilian waters may have been displaced during seismicsurveys over a 10-year period where decreasing cetacean densitycorrelated with increasing seismic surveys, but did not correlatewith any oceanographic parameters (Parente et al., 2007).

Similarly, Macleod et al. (2006) observed an unusual distribu-tion pattern in whales off the west coast of Scotland during a largescale survey there in 1998. They postulated that the surprising ab-sence of fin, Balaenoptera physalus, and sei whales, Balaenopteraborealis, to the west of the Hebrides (compared to a high densityof large whales in the adjacent more northerly Faroe-Shetlandchannel) might relate to seismic activity. Whilst other contributingfactors could not be ruled out, seismic activity was notably greaterin the area lacking whales than further north. Furthermore,McCauley and Duncan (2001) stated that airguns could elicitbehavioural changes at a range measured in tens of km in bluewhales, Balaenoptera musculus, and probable avoidance at3–20 km. Miller et al. (2005) describe similar results for belugawhales, Delphinapterus leucas and McCauley et al. (2000) also dis-covered that humpback whales, Megaptera novaeangliae, off Ex-mouth, Australia, responded to seismic testing in various waysand at distances that were not observable from the survey vessel– females with calves were particularly sensitive and were re-ported to show aversive reactions at 7–12 km from seismic vessels(McCauley et al., 1998). The longest-term study of cetacean andseismic interactions began in the Alaskan Beaufort Sea in the1980s. Data collected since then have shown that behavioural re-sponses in bowhead whales, Balaena mysticetus, have occurred asfar away as 30 km from the source (where received levels were107–126 dB re 1 lPa rms; Richardson et al., 1999). Thus studieshave shown, at least for some species, and groups of animals suchas cow–calf pairs (e.g. McCauley et al., 1998), that reactions mayoccur at very substantial distances from seismic sources.

Examination of effects of large airgun arrays (13 or 16 airgunswith a total volume of 79–110 l with an effective source level of260 dB re 1 lPa @ 1 m; Bain and Williams, 2006) on a variety ofmarine mammal species in the waters of British Columbia andWashington identified behavioural changes in some species at dis-tances of more than 70 km (Bain and Williams, 2006). Two por-poise species (harbour porpoise, Phocoena phocoena, and Dall’sporpoise, Phocoenoides dalli), showed drastically different re-sponses despite being thought to have similar hearing sensitivities:both species showed avoidance behaviour but Dall’s porpoiseswere found in areas receiving exposures of 170–180 dB re 1 lPa,whereas harbour porpoises showed reactions at received levels<145 db re 1 lPa rms at a distance of more than 70 km from theseismic source (Bain and Williams, 2006). Therefore, there maybe substantive species-specific differences in cetacean reactions.Furthermore, hearing may only constitute one part of the combina-tion of factors that determine an individual’s response to an expo-sure to noise (see Beale, 2007 and Wright et al., 2007a, and thereferences therein).

Clearly onboard measures to monitor animals around the air-guns are not enough to protect individuals and populations. Thisis particularly the case over the longer-term and when taking intoaccount cumulative impacts, which are much more challenging to

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study (see below). Scheduling surveys around seasonal distribu-tions of species of concern, limiting periods of exposure (by limit-ing the duration of the survey), and routing airguns to ensure thatmarine mammals are not driven ashore may be as important asmonitoring safety zones in preventing possible injury and death,let alone disturbance (Bain and Williams, 2006). However, thesimplest way to mitigate the effects of seismic surveys on marinefauna is to avoid animals either in space or time (Agardy et al.,2007; Dolman, 2007). The designation of spatio-temporal restric-tions is most effectively implemented at the government level ineach region as part of standard statutory guidelines, where the leg-islation applies to and is adopted equally by all marine users. TheJNCC should investigate and implement such measures as a matterof urgency.

4. Specific mitigation measures

4.1. Soft start

As mentioned above, a major mitigation method offered by theJNCC guidelines is the ‘soft start’ or ‘ramp-up’. According to theguidelines, this is ‘‘to give adequate time for marine mammals toleave the vicinity” (p. 4, JNCC, 2004). However, as noted by Wier(2008a): ‘‘Although the ramp-up procedure is the most widelyused seismic mitigation measure worldwide, it is currently imple-mented as a common sense procedure, and there is little informa-tion on its efficiency in evoking an appropriate response frommarine mammals” (p. 349). Stone and Tasker (2006) noted no dif-ference in the distance of cetaceans from seismic arrays when sys-tems were ramping up (compared to periods when airguns wereoff or in full operation), although Wier (2008a) notes that ‘‘thisfinding is based on simple sketches (often by inexperiencedobservers) of animal movement relative to a ship and uses com-bined datasets from many different airgun configurations, species,and water depths” (p. 353).

Wier (2008b) did however observe Atlantic spotted dolphins,Stenella frontalis, moving away from a vessel during a ramp-up.To date the most detailed observation of cetacean behaviour dur-ing a ramp-up is Wier (2008a) who noted that for one group of pi-lot whales animals substantively altered their direction ofmovement and surface behaviour, moving away from the source,nine minutes into the survey (when the airguns had reached940 cu3 volume; Wier, 2008a). However, interpreting the reactionsof whales to the seismic source is problematic, as Wier notes: ‘‘thecontinued logging [animals floating, exhibiting low activity] of pi-lot whales at the surface during a ramp-up procedure could beinterpreted as a lack of marked avoidance response to increasingairgun volume. Alternatively, the same observation could be ex-plained by animals spending more time at the surface in a verticalavoidance response to higher levels of received sound in the lowerwater column (p. 353, Richardson et al., 1995)”.

In addition to the criticisms discussed above, some species mayavoid a disturbance vertically rather than horizontally; that is, bysurfacing or diving, which perversely may leave them more vulner-able to certain acoustic or other impacts. For example, a study byNowacek and colleagues showed a surprising response by North-ern right whales, Eubalaena glacialis, to alarms designed to alertthem to the presence of ships – an avoidance reaction that was lar-gely vertical rather than horizontal and, in the case of the rightwhale, actually made them more vulnerable to ship strike, a majorconservation threat to this species (Nowacek et al., 2004). Forbeaked whales and other deep-diving cetacean species (e.g., Kogiaspp.), disruption of normal diving patterns, either an escape reac-tion that drove the animals towards the surface or induction of aprolonged near-surface period, could potentially cause the onset

of decompression sickness-like effects (e.g., Jepson et al., 2003;Fernández et al., 2004; Tyack et al., 2006). Whilst soft start mayseem a ‘common sense’ approach, urgent efforts to assess its effec-tiveness are required. The JNCC and other agencies that enforcesoft start as a mitigation measure have a responsibility to under-take this work.

4.2. Source shut down

Once the survey is operating under full power there is no obli-gation under the JNCC guidelines for operators to shut it downonce an animal or group of animals approaches the source. Thisis unlike mitigation during naval active sonar operations (Dolmanet al., 2008) or during seismic operations off the United States andin certain other jurisdictions (Weir and Dolman, 2007), where theuse of an exclusion-zone (EZ) (or ‘safety-zone’) is standard practice.An EZ is usually defined as the radius around the sonar sourcewithin which real-time mitigation measures are implemented ifanimals are detected. Failing to shut down the source when ani-mals have approached within a predetermined distance of thesource is intentional disturbance. This is a mitigation measure thatcould and should be initiated on all seismic survey vessels, withimmediate effect.

4.3. Visual monitoring

Many of the cetaceans potentially present during seismic sur-veys include deep-diving species such as sperm and beakedwhales. Researchers have noted that the probability of observersactually sighting a beaked whale in the zone of acoustic impactis generally less than 1% (Barlow and Gisiner, 2006). This makes vi-sual surveys for such deep-diving species largely ineffective.

Other cryptic species include the harbour porpoise, one of themost frequently encountered cetacean species in much of theUK’s waters. In addition, a number of other variables that relateto both the observer (such as training, experience, and enthusiasm)and the environment (including increasing sea states, time of day,and adverse weather conditions) can significantly hamper visualdetections. The guidelines should reflect such limitations and man-age them appropriately by clearly documenting them and adoptingprecautionary spatio-temporal measures. These could include sub-stantially reducing or postponing seismic activities during periodsof low visibility if the probability of detection of cetaceans in thearea is poor (also see the environmental factors section below).

4.4. Marine mammal observers

The JNCC guidelines require dedicated marine mammal observ-ers (MMOs) with several seasons’ monitoring experience forwaters off the UK’s west coast and within EU Habitats Directivedesignated Special Areas of Conservation (for example, the MorayFirth in Scotland and Cardigan Bay in Wales). Observers are also re-quired outside of these areas, but they do not need any experienceor expertise. Indeed, they need not ever have seen a cetacean at seabefore. However, the use of experienced observers is increasinglybecoming standard in the UK, although lack of experience is com-mon for observers in many other countries.

Wier (2008a) notes that many MMOs working on seismic ves-sels have little field experience with free-ranging cetaceans or withscientific data collection and may not be able to appropriately as-sess and record behavioural and directional changes by animals”(p. 353). Knowledge of cetacean behaviour is essential if one is tobe able to assess with confidence whether animals are being im-pacted, or not, by seismic survey activity.

Training provided to observers is extremely variable amongstdifferent agencies and jurisdictions. In the US, MMOs for seismic

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surveys may be required to take a 2-day training course or haveseveral weeks of in-field experience. A poor example of ‘training’given by one agency merely involves watching a 45-min DVD.Ideally MMOs should not need training in cetacean identification– they should already have several years of in-field experience.Novices should work alongside experienced MMOs until suitablycapable.

Appropriate experience is an important criterion in the selec-tion of effective field observers. The JNCC guidelines should requirethat observers are experienced regardless of location. The require-ments should include that observers are able to spot and identifyaccurately all cetacean species likely to be encountered and haveexperience in conducting surveys in environmental conditions thatare common in the surveyed areas, which in the UK, for example,could include heavy seas and poor visibility.

The importance of using experienced MMOs is shown by theBritish government’s own research (Stone, 2003a). When marinemammals were detected within the 500 m zone of impact by ded-icated, experienced MMOs, the guidelines were followed and thesurvey was delayed 70% of the time. This figure fell to 0% whenFisheries Liaison Officers or ship’s crew were used. Unfortunately,MMOs were used on only 19% of Government monitored seismicsurveys during this period. Fisheries Liaison Officers and ship’screw were relied upon for other surveys (56% and 20%, respec-tively; Stone, 2003a).

Under the JNCC guidelines, only one dedicated observer is re-quired, which also reduces the likelihood of cetaceans beingsighted. Indeed, JNCC regulations emphasise that at ‘‘no time arethese guidelines meant to imply that [MMOs] should keep a watchduring all daylight hours” (p. 4, JNCC, 2004). The requirement toshut down currently only extends to periods of ramp-up. However,MMOs would be required in sufficient numbers to watch continu-ously throughout the survey period if shut downs become arequirement whenever an animal enters a predetermined exclu-sion-zone, as suggested above.

In contrast to the single observer often used to monitor seis-mic surveys, dedicated cetacean surveys usually use two teamsof two to three observers who survey the sea simultaneously –and still animals are not observed (hence the need for the g0 cal-culation – the likelihood that animals would be observed under aset of environmental conditions when directly in front of a surveyvessel, in order to estimate missed animals). Typically, cetaceansurvey observers are rotated to prevent them from becoming fati-gued and losing concentration. This process is generally followedin the US by observers searching for manatees and sea turtles un-der the purview of the US Fish and Wildlife Service. Thus, thenumber of MMOs required by the JNCC guidelines should be in-creased and a maximum length for observer shifts should beestablished.

4.5. Passive acoustic monitoring (PAM)

In the JNCC guidelines, passive acoustic monitoring or PAM(that is, listening for cetacean vocalisations), in real-time, is gener-ally suggested as an additional monitoring method and can be re-quired by the JNCC for surveys in particularly sensitive areas. Notonly can PAM detect vocalising diving animals, but it can also de-tect vocalising animals at night and in rough weather conditions(Gordon and Tyack, 2002). PAM has great potential for detectingcetacean species that vocalise frequently such as sperm whales,which would reduce a number of the concerns noted above for vi-sual surveys. However, PAM can only detect cetaceans when theyvocalise and no species vocalises constantly (Gordon and Tyack,2002). One study on common dolphins in the UK showed thatalthough vocalisation rates were relatively high at night, they de-creased for portions of the day (Wakefield, 2001).

Also, anthropogenic sounds have, on occasion, been shown tocause cetaceans to cease vocalising. For example, as noted above,fin whales ceased all vocalisation during seismic surveys and didnot resume vocalising for hours or days afterward (Clark andGagnon, 2006). Sperm whales have also decreased vocalisationsor become completely silent in response to seismic surveys (IWC,2007), as well as in the presence of pinger sounds (Watkins andSchevill, 1975), mid-frequency military sonar signals (Watkinset al., 1985), and low-frequency anthropogenic sounds (Bowleset al., 1994). Nevertheless, real-time PAM should be used in con-junction with visual observation, to maximize the probability ofdetection.

5. Factors not adequately considered in the JNCC guidance

5.1. Number of airguns

The JNCC guidelines do not appear to take into account thenumber of airguns used in an array. In general, the greater thenumber of the airguns, the greater the sound output. For example,one study measured a received level of 160 dB at 2.7 km from anarray when six airguns were in use (Tolstoy et al., 2004). As thenumber of airguns increased, so did the distance at which a re-ceived level of 160 dB was recorded, reaching 9 km with 20 airguns(Tolstoy et al., 2004). Airgun size (and thus power) is another lar-gely unconsidered factor. Therefore, the zone of impact, the areamonitored, and the mitigation measures applied should increaseaccording to the number and size of the airguns used.

5.2. Environmental factors

Little consideration is given to environmental factors thatwould be expected to reduce the observer’s ability to spot ceta-ceans, such as fog, rain or rough seas. Scientific surveys for ceta-ceans are often not conducted in sea states greater than Beaufort3 or 5, depending on the study species, as rough weather severelyreduces the ability to see cetaceans. Further, there are no prohibi-tions on conducting seismic surveys at night, when visual surveysare almost completely useless. (Even the use of night-vision glassesis rendered ineffective by lights on board vessels). At a minimum,the JNCC guidelines should not allow seismic surveys relying onobservers as a mitigation measure in sea states > 5, during fog orheavy precipitation, or at night, when visual surveys areineffective.

5.3. Oceanographic effects

The 500 m zone of visual observation does not take into accountvariations in acoustic propagation between locations, or even at asingle location at different times, that arise from combinations offactors such as weather conditions, depth, temperature or salinity.For example, researchers have noted differences in sound trans-mission from seismic surveys between deep and shallow waters(Tolstoy et al., 2004).

Detailed studies should be conducted to calculate receivedlevels at various distances from a seismic source during planningstages. These should be ground-truthed in the field in advance offiring, in order to measure the effects of oceanographic factors.At a minimum, a short period of controlled and monitored testfiring should be included in the JNCC guidelines. In addition, aprecautionary zone should be designated, which takes into ac-count the oceanographic conditions that could cause a maximumtransmission of sound – in other words, which considers theworst-case scenario for sound transmission from the airgunarray.

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5.4. Other species

The current JNCC guidelines do not consider the impacts of seis-mic surveys on cetacean prey species, such as fish and squid, whichare known to be vulnerable to airgun noise (McCauley et al., 2003;MacKenzie, 2004). To avoid secondary, trophic-level effects, not tomention detrimental consequences to the fishing industry, thesespecies should also be considered in management plans.

5.5. Compliance and enforcement

Management agencies generally assume that the oil and gasindustry and others using seismic airguns will adhere to seismicguidelines, as there is often no governmental monitoring of seismicactivities or enforcement of the guidelines. Such voluntary systemsfrequently have poor compliance (Rachlinski, 1998; Rivera and deLeon, 2004; Wiley et al., 2008). As mentioned above, limited com-pliance specifically with the JNCC guidelines has also been re-ported (Stone, 2003a,b,c). This aspect of the regulatory regimerequires consideration: compliance with the guidelines, given theirstatutory nature in the UK, should be independently monitoredand any regulations requiring their use should be enforced. A min-imum of one governmental or independent observer shouldaccompany all seismic surveys in sensitive areas, and periodicallyin other locations, to oversee and monitor activities. MMO reportsshould be sent straight to the JNCC (or other government agency)to prevent tampering and removal of data.

6. Guidance for other intense sound sources

Whilst the JNCC has developed guidance for seismic surveysover a number of years, guidance for pile-driving and explosionsare a recent development (JNCC, 2008). Since shipping, marineand coastal construction (e.g., blasting and pile-driving) and activenaval sonar are recognised as other major noise producers, it willbe important for the UK and European governments, and indeedall countries that operate or permit such noise sources, to recog-nise their environmental responsibilities (under the EU HabitatsDirective or other legislation) to protect cetaceans, pinnipeds andother marine species from disturbance by intense noise sourcesand to develop clear, concise and appropriate guidance for users.

7. Cumulative impacts

Operational guidelines are concerned only with the reduction ofimmediate effects. However, some of the more insidious, andpotentially devastating, impacts arise through long-term, repeated,persistent or cumulative exposures. For example, marine mammalsthat have been exposed to high levels of contaminants, eitheracutely or over long periods, can be expected to be more suscepti-ble to detrimental consequences of exposure to other stressors,including noise from seismic surveys (see Wright et al., 2007b).Consideration of such possibilities is needed at the planning stagesto meet the requirements of the EU Habitats Directive, the Cana-dian Environmental Assessment Act, various US statutes, and otherlegislation around the world.

8. Conclusions

The UK, like other EU member states, is required to establish asystem of strict protection for the animal species listed in Annex IVof the EU Habitats Directive 92/43/EEC which includes all ceta-ceans. The requirement for strict protection is clearly not beingmet through the current guidelines. Significantly, visual surveysalone as a ‘mitigation measure’ appear to be little more than a pub-

lic relations exercise and may even be doing more harm than good.They may be giving management authorities, oil and gas compa-nies, and the public a false sense of security that seismic survey im-pacts are being mitigated and that environmental requirementsare being met. Increasingly it is being realised that this is not thecase. On-board mitigation measures have serious limitations andcannot guarantee the protection of the focus animals. For one, theyare unlikely to detect all marine mammals within the designatedzone of impact and thus fail to be effective at protecting them. Fur-thermore, simply because animals are visible in an area and are notvisibly fleeing from a seismic survey vessel does not mean thatthere is no significant impact; thus any reliance on such observa-tions to determine the zone of impact may well be flawed. Finally,they do not address the potentially significant biological impactsoccurring at much broader temporal and spatial scales.

As noted earlier, the simplest way to mitigate the effects ofseismic surveys and other high-intensity noise sources on marinefauna is to avoid animals either in space or time (Agardy et al.,2007; Dolman, 2007). Spatio-temporal restrictions require knowl-edge on the distribution, density and seasonal occurrence of ceta-ceans in an area. In some regions the occurrence of marinemammals is well documented. However, this basic informationis lacking for many parts of the world and for some species(e.g., beaked and Kogia whales). Species distributions oftenchange over time and this may be exacerbated or acceleratedby climate change-driven effects (Simmonds and Isaac, 2007).Hence, distribution and abundance surveys need to be up to dateand frequently repeated to ensure that guidance includes theappropriate spatio-temporal restrictions. This will allow the ani-mals to be protected, while not unnecessarily limiting industryactivities in areas where animals are absent, or in areas of lowhabitat value. In some regions worldwide there is little awarenessof the potential effects of seismic activities on marine mammals,and such countries should be strongly encouraged to considermarine mammals and other sensitive marine fauna early in theplanning process and implement spatio-temporal restrictions asappropriate. Some jurisdictions, such as Brazil, have already insti-tuted such restrictions during the leasing process (Agardy et al.2007).

The JNCC guidelines and, by extrapolation, those seismic surveyguidelines in other regions of the world that have used the JNCCguidelines as a model (see Weir and Dolman, 2007) offer ananthropocentric ‘common sense’ approach to species protectionfrom intense noise sources. However, in light of recent researchand detailed study of observable impacts, these do not appear tobe consistent with the actual or likely behaviour of marine mam-mals. Consequently, these guidelines do not meet the required leg-islative standards and are not adequately precautionary.

To summarise, guidelines should be reviewed and updated withmeasures that are intended to ensure adequate species protectionand to address data gaps. Primarily, the designation of spatio-tempo-ral restrictions as a mitigation strategy is urgently required. Furtherprecautionary measures that should be initiated immediately in-clude, but should not be limited to:

� Requirement for evaluation of cetacean occurrence, distributionand abundance as part of Marine Spatial Planning, before sitesare licensed, and well before seismic surveys start.

� An adaptive planning process, open to change with improve-ments in available information and with a more precautionarystarting point where data are lacking.

Further, there should be a requirement for more comprehensivemonitoring during seismic survey activity. Guidance should ad-dress the following on-board measures, which should be a require-ment during all future seismic surveys:

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� Designation of zones of impacts based on ‘worst-case scenarios’for sound propagation.

� Shut-down of the sound source if animals enter the biologicallymeaningful ‘zone of impact’ during surveys.

� Assessment of the efficacy and potential confounding effects of‘soft starts’.

� Postponement, or substantial limitation, of seismic survey activ-ity during periods of low visibility and adverse weatherconditions.

� Explicit requirement for marine mammal observers to be quali-fied and experienced (e.g., have conducted a substantive numberof survey hours in environmental conditions common to thearea).

� Increasing the number of marine mammal observers required,and limiting the shift length of these observers to improvedetection of cetaceans in zones of impact.

� Use of passive acoustic monitoring in conjunction with visualsurveys while recognising the limitations of this method.

� Taking into account the size and number of airguns used whendeveloping a mitigation strategy.

� Use of scientific data on adverse reaction in species, making the‘zone of impact’ biologically meaningful and determining theareas that must be monitored for cetacean occurrence.

� ‘Ground truthing’ of sound propagation during various oceano-graphic conditions.

� Consideration of the effects of seismic surveys on prey species inmanagement decisions.

� Requirement that marine mammal observers report directly tomanagement authorities.

� Requirement that at least one independent or governmentalobserver accompany seismic surveys in sensitive areas to ensurecompliance.

� Consideration of the cumulative impact of chronic exposure tonoise sources, including seismic surveys, and other anthropo-genic factors.

Finally, with regards to evaluating the effectiveness of mitiga-tion measures, there should be emphasis on, and acknowledge-ment of, the fact that simply because animals are visible in anarea and are not visibly fleeing from a seismic survey vessel doesnot mean that there is no significant impact, i.e. absence of evi-dence is not the same as evidence of absence with respect to theimpacts of underwater noise on cetaceans.

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