The Negative Side Of Whale Watching

Introduction

In recent decades, there has been a dramatic shift in the way in which people relate to the larger marine mammal species (Williams et al, 2002:255). In 1993, the International Whaling Commission (IWC) promoted the further development of whale watching as a sustainable way to protect the cetacean species (IWC, 1994). There are obvious economic and conservation benefits to this ecotourism business. The International Fund for Animal Welfare (2009:7) claims that more than 13 million people took whale watching tours in 119 different countries in 2008, with an estimated revenue of $2.8 billion. Many areas have seen a decline in regional fisheries over the past two decades, resulting in high levels of unemployment, poverty and conflicts over common-pool resources (Young, 1999:584). Nevertheless, the decline in the fishing industry has been concurrent with a rise in ecotourism, resulting in increased economic opportunities for out-of-work fishermen and the enhanced tourist development of some economically deprived areas (Wilson and Tisdell, 2003:49-58). Duffus and Dearden (1993:150) claim that the whale-watching business has allowed millions of urban dwellers to observe these marine animals in their natural environment leading to greater understanding of the ecological problems faced by these creatures. Duffus and Dearden (1993:153) further suggest that this may help to change attitudes on the protection of critical species and their habitats.

However, growing numbers of whales are being targeted by ecotourism, which has led to claims that their over-exposure to whale-watching holiday makers is having a negative effect on the health and behaviour of the cetacean species (Lusseau et al, 2009 Williams et al, 2009 Schaffar et al, 2013 Lachmuth et al, 2011). Pressure from boat activity changing the behaviours of the cetaceans, the effect of increased tourism to environmentally sensitive areas and the health effects of boat exhaust fumes and noise levels are all subjects that have been extensively studied, with sometimes contradictory results. This essay will critically evaluate the available literature surrounding the negative effects of whale-watching including any effect that the industry may be having on the health and behaviour of these cetaceans.

The Impacts of Whale Watching

Sperm Whales

Richter et al (2003) carried out an extensive study on the behaviour of sperm whales (Physeter macrocephalus) off the coast of Kaikoura, New Zealand. In their four year-long study, they recorded 676 sightings from their research vessel and 435 from shore and analysed the blow interval, time spent on the surface, direction changes, vocal activity and aerial activity of the whales. They recorded these behaviours whilst in the presence of whale watching boats or the research vessel and when no vessels were near. They found that both the mean and median blow interval decreased in the presence of any vessel, with the whales spending more time on the surface. They also discovered that the whales carried out more heading changes when whale watching vessels were nearby. Additionally, the presence of vessels limited the number of aerial displays carried out by the whale. The vocalisations of the whales also changed in the presence

of vessels, with the resident whales (whales that resided in the area for 42 days or more) decreasing the time to first click after diving by approximately 10 seconds. Conversely, transient whales (whales that stayed in the area for only a few days) increased the time to first click after diving by up to 20 seconds. The authors state that changes in the behaviour of the whales did vary widely between the transient and resident whales, with the latter group being more tolerant of vessels and displaying less aversive behaviour than the former group.

However, it is considered that this apparent tolerance does not imply a lack of impact. On the contrary, the very nature of tolerance implies that a disturbance or annoyance is endured due to the necessity of a particular activity (feeding, breathing, communicating etc.) or the importance of the location for breeding or feeding purposes (IFAW, 1995:8). As such, it is important to understand that because an animal does not actively avoid human contact, does not then mean that the animal is altogether comfortable with having the humans around. Knight and Cole (1995:51-69) explained the same behaviour in land animals exposed to safari vehicles. They explain that most targeted species habituate to the presence and activity of humans over time, providing they do not feel threatened. Additional studies on other cetacean species, such as minke and fin whales show that these species have learned to either ignore whale watching vessels or actively seek them out in an inquisitive way (Mangott et al, 2011:64-76). However, this behaviour is species specific and requires further study to fully understand the actions of these whales.

Whilst the evidence presented by Richter et al (2003) is both comprehensive and convincing, another similarly designed study on sperm whales carried out by Magalhaes et al (2002), reports contradictory results. They studied the behaviour of sperm whales in the Azores from both land based lookouts and from whale watching vessels. The results show that the aerial activity and swim speed of the whales increased when in the presence of boats and that their blow frequency also increased. One reason for these contradictory results could be due to the differences in gender between the two whale groups. Female and young sperm whales reside in warmer waters in either tropical or sub-tropical areas whilst the males form loose pods or remain largely solitary and expand their territories into cooler waters (Richter et al, 2003:10). Thus, it is considered that the whales in the Richter study were largely males, whilst the whales in the Magalhaes study, carried out in warmer climes, were more likely to be females with calves.

In addition to these gender differences, there are concerns over the reliability of the Magalhaes et al (2002) study. Despite the study results showing a marked increase in blow frequency, swim speed and aerial activity in the presence of boats, the authors report that there was no adverse impact on the behaviour of the whales. Additionally, only 104 sightings were recorded with 64 of these being sighted from land at a distance of up to 10 nautical miles. Richter et al (2003:15) reported difficulty of gaining reliable results from land based observations as blows could be difficult to spot at greater distances. With more than 61% of the Magalhaes et al (2002) study relying on these land based observations, one must question the accuracy of these recordings.

Killer Whales

Jelinski et al (2002) considered the effects that commercial whale watching vessels have on the spatial dispersal and behaviours of killer whales (Orcinus orca) in the Johnstone Strait, Canada. They observed and analysed 260 sightings, in which they recorded whale swim speed, orientation and spacings within the pod. Jelinski et al (2002:409) reported that whale behaviour was adversely affected by these whale watching vessels, with the whales moving out to deeper waters in the presence of boats. They also reported that the spatial dispersal of the whales within the pod was also significantly affected by motorised boats with the whales drawing closer together when in the presence of boats emitting high noise levels. One theory on this behaviour is the way in which the killer whales communicate when hunting, emitting clicking noises or discrete calls to maintain pod cohesion and coordinate activities (Ford, 1989:727). The masking effect of the boat engines may necessitate the closer formation of the pod to ensure all vocalisations are heard.

Erbe’s (2002) study furthers this theory. She recorded the underwater noise of whale watching boats in the Haro Strait, Canada and applied software sound propagation and an impact assessment model. These were used to estimate zones around the whale watch boats within which the boat noise was audible to the killer whales. Erbe (2002:397) discovered that boat source noise levels ranged from 145 to 169 dB at 1 metre distance. Fast boats, travelling at 51km per hour, with engines of 150hp or over, were audible from a distance of 16km and were shown to mask the calls of killer whales at a distance of 14km. Erbe (2002:402) also showed a 5dB temporary threshold shift in killer whales subjected to this noise level for a period of between 30 and 50 minutes, at 450m distance. These distances were greatly reduced with smaller engined boats or when the faster boats were idling or cruising at low speeds of less than 10 km per hour. At slow speeds, the audible and masking range was shown to be around 1km and for temporary threshold shift, the boat would need to remain as close as 20 meters for over half an hour.

Despite Erbe’s (2002) study providing strong evidence on the need to maintain, or even extend, the current guidelines of 100 metre distance between the boats and the whale, there was a lack of information within the study regarding the distance upon which the killer whales calls were masked. Instead, Erbe (2002:400) masks a ‘barely audible’ killer whale call but fails to explain over what distance this call would be audible to a killer whale. As such, there is a lack of evidence to suggest that the masking effect of boat noise at 14km will have any major effect on the hunting or breeding behaviours of the killer whales. However, the results of Jelinski et al (2002) would suggest that these noises do alter the communication behaviour of the whales. Additionally, Foote et al (2004:910) reported a change in the vocalisations of killer whales whilst in the presence of motorised vessels, explaining that the length of each call increased significantly when compared to the whale calls in the presence of non-motorised vessels. This would suggest that the presence of motorised whale watching vessels is eliciting a behavioural modification of the whales who are ‘learning’ to increase their call duration to ensure they can be heard.

Whilst most studies have analysed the behavioural responses to whale watching boats,

Lachmuth et al (2011) analysed the health effects of increased exposure to exhaust gases on these marine mammals. Lachmuth et al (2011) used a simple dispersion model to ascertain the levels of exhaust pollution each whale was exposed to on a daily basis. Within their study, the authors disclosed that the killer whales within the two study areas (Southern Vancouver Island, British Columbia and Puget Sound, Washington DC) had, on occasion, as many as 120 vessels within an 800 metre radius of them. Additionally, during the 12 hours of daylight, each whale had an average number of 20 boats around it for 99.5% of the time. These shocking statistics undoubtedly have a negative effect on the general well-being of the whales if the findings of the previously mentioned studies are correct. However, Lachmuth et al (2011) discovered that exhaust pollutant exposure was successfully limited with current guidelines restricting the whale to boat distance of 100 metres. Nevertheless, the authors do caution that in worst case scenarios, in situations of high boat traffic located upwind of the whale, then limits of exposure regularly exceeded the Air Quality Guidelines (AQGs) presented by the World Health Organisation (Lachmuth et al, 2011:798). Whilst the results in this study do serve to caution against any decrease in whale to boat distance, care must be taken in interpreting these findings. As yet, there is no evidence to suggest that the killer whales are affected by CO and NO2 in the same way as humans. As such, the AQGs presented in the Lachmuth study may not be representative for this population, although the authors predict that they may be more sensitive than humans due to the respiratory function and dive pressures endured by these cetaceans.

Conclusion

In conclusion, it is considered that whale watching activities do have a negative impact on the health and behaviours of both sperm and killer whales. The behaviour of sperm whales is negatively affected by the presence of these boats. Blow frequency, swim speed, dive duration and multiple heading changes are frequently reported when whale watch boats are present. In addition, the presence of these boats affects the aerial displays of these cetaceans. There is some contradictory evidence presented within this study surrounding the behaviours of sperm whales, however, it is considered that these differences can be explained through the likely gender differences between the whale groups studied.

Killer whales have been extensively studied with concerns being voiced over their exposure to exhaust fumes. Whilst the study failed to provide any conclusive proof over the adverse effects that these fumes may have on the health of these cetaceans, it is clear that the sheer number of boats in the vicinity of these marine mammals for such extensive periods will undoubtedly have a negative effect on their health. However, further research is needed in this area. What is clear is that killer whales are negatively affected by the noise of the whale watch vessels. Evidence suggests that the masking of killer whale calls by the engines of the boats has resulted in a change in behaviour with whales swimming closer together whilst in the presence of motorised vessels. Additionally, their call duration also increases, leading to the suggestion that these whales are adapting to the ecotourism trade. As previously mentioned, one must take care in assuming that the adaptation of behaviour decries the negative impacts that this industry has on this species. Indeed, it is considered that the forced change in the behaviour of any individual in

order to survive is fundamentally wrong and goes against the concept of conservation. To conserve a species, one must ensure that it is able to maintain its usual behaviours and habits in a healthy and safe environment.

References

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