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Killer whale evasive tactics vary with boat number
Abstract
Controlled exposure experiments that measure animal response to vessels can inform relevant wildlife-viewing guidelines and reveal how they make decisions about changes in their environment. Previous experimental studies documented stereotyped avoidance responses by killer whales to boats. Additional observations collected during these studies showed an apparent shift in avoidance behaviour at high traffic levels. Our study tested experimentally whether whales did respond differently to approach by few (1–3) versus many (>3) vessels. Data were collected in summer 2004 in Johnstone Strait, British Columbia, using a theodolite to track the positions of boats and individually identifiable focal whales during control and treatment (few vs. many boats) phases. The responses of 16 adult male killer whales differed significantly between treatment levels (Wilcoxon's test, P=0.0148). Swimming paths became more tortuous when few boats approached whales, but straighter as many boats approached. Pooling treatments would have masked significant responses with high statistical confidence (Wilcoxon's test, P>0.999), falsely suggesting that boat presence had no effect. The division between few and many boats was supported by 140 opportunistic observations on 26 whales from a population of 216. We used generalized additive models to control for the effects of confounding variables, detected a non-linear relationship between number of boats and whales' swimming path directness and confirmed an inflection point at approximately three boats within 1000 m. We urge caution when designing controlled exposure assessments that rely on a simple absence–presence framework, which can mask multivariate or non-linear responses. Experimental design, coupled with analytical techniques incorporating statistical power and appropriateness of treatments and response variables, must be considered when interpreting the biological significance of null findings from impact assessments. Our study provides new information about levels of habitat degradation that this marine apex predator can tolerate.
... Such behavioral variations may produce additional energy costs for the individuals (Williams et al., 2006;, affecting their body condition in the medium and long-term, as well as the state of health and the reproductive success of the animals (Lusseau, 2005;Bejder et al., 2006b), which may eventually represent a threat to the conservation of the species exposed to WW (Corkeron, 2004;Lusseau and Bejder, 2007;Parsons, 2012). The other most frequent short-term effect reported is horizontal evasion, indicated by changes of direction in the movement patterns of the animals (Scheidat et al., 2004;Williams and Ashe, 2007;Williams et al., 2009;Schaffar et al., 2013;. Thus, in the presence of boats, movement patterns become less predictable as linearity decreases (the straight-line trajectory is lost) and reorientation increases (erratic trajectory) in order to evade the boats (Scheidat et al., 2004;Williams and Ashe, 2007;Schaffar et al., 2013). ...
... The other most frequent short-term effect reported is horizontal evasion, indicated by changes of direction in the movement patterns of the animals (Scheidat et al., 2004;Williams and Ashe, 2007;Williams et al., 2009;Schaffar et al., 2013;. Thus, in the presence of boats, movement patterns become less predictable as linearity decreases (the straight-line trajectory is lost) and reorientation increases (erratic trajectory) in order to evade the boats (Scheidat et al., 2004;Williams and Ashe, 2007;Schaffar et al., 2013). These evasion tactics vary depending on the number of boats and the approach distance (Williams et al., 2009;Schaffar et al., 2013). ...
... It has been shown that humpback whales (Megaptera novaeangliae) change their trajectory continuously when boats are close (Schaffar et al., 2013). It has been shown that the displacement trajectory of orcas (Orcinus orca) becomes more linear as the number of boats increases, indicating that the evasion tactic (increase in reorientation) may not be effective in the presence of a larger number of boats (Williams and Ashe, 2007;Williams et al., 2009). If evasive tactics are not effective, cetaceans must use strategies that are more energetically costly (Morete et al., 2007;Sprogis et al., 2020a,b), such as an increase in the velocity of displacement in the presence of boats Sprogis et al., 2020b). ...
Whale-watching (WW) is an activity which has been increasing worldwide due to the great interest of tourists and the economic benefits it provides to local communities. However, it has been reported that this activity affects the behavioral patterns of some cetaceans, although for some species such as the fin whale (Balaenoptera physalus) this has not been extensively studied. To identify the effects of WW on the behavioral patterns of this species, we studied its traveling and resting behaviors in a locality of north-central Chile from 2015 to 2018. Using a theodolite, we calculated the response variables of swim speed, directness index, and reorientation for each behavior. We used the number of WW boats and the WW scenarios of “before”, “during”, and “after” the presence of boats as possible factors to explain the differences in the response variables of the whales, along with the factors of year, month, group size, and distance from the observation point. Reorientation increased significantly and the directness index decreased significantly for both traveling and resting behaviors from “before” to “during” WW scenarios, indicating more erratic and sinuous movements in the presence of boats. These changes in movement patterns are a commonly reported evasion response of cetaceans to the presence of WW boats. For traveling behavior, the swimming speed significantly increased, and trends showed increased reorientation and a decrease in the directness index in the “after” WW scenario, which suggests perturbation of the whales potentially associated with the speed and the direction in which the boats left. During resting behavior, the trajectories of the fin whales became straighter (decrease in reorientation) as the number of boats increased, thus evasion (more erratic and sinuous movements) is a behavior used less by fin whales as the number of boats increases. Notwithstanding the fact that tourism development in the study area is small in scale, we found that WW generates adverse effects that are reflected in changes in the whales’ movement patterns. This kind of information is valuable to the adjustment and/or design of management strategies for the species, which is fundamental for WW to continue to be a sustainable activity.
... Such behavioral variations may produce additional energy costs for the individuals (Williams et al., 2006;, affecting their body condition in the medium and long-term, as well as the state of health and the reproductive success of the animals (Lusseau, 2005;Bejder et al., 2006b), which may eventually represent a threat to the conservation of the species exposed to WW (Corkeron, 2004;Lusseau and Bejder, 2007;Parsons, 2012). The other most frequent short-term effect reported is horizontal evasion, indicated by changes of direction in the movement patterns of the animals (Scheidat et al., 2004;Williams and Ashe, 2007;Williams et al., 2009;Schaffar et al., 2013;. Thus, in the presence of boats, movement patterns become less predictable as linearity decreases (the straight-line trajectory is lost) and reorientation increases (erratic trajectory) in order to evade the boats (Scheidat et al., 2004;Williams and Ashe, 2007;Schaffar et al., 2013). ...
... The other most frequent short-term effect reported is horizontal evasion, indicated by changes of direction in the movement patterns of the animals (Scheidat et al., 2004;Williams and Ashe, 2007;Williams et al., 2009;Schaffar et al., 2013;. Thus, in the presence of boats, movement patterns become less predictable as linearity decreases (the straight-line trajectory is lost) and reorientation increases (erratic trajectory) in order to evade the boats (Scheidat et al., 2004;Williams and Ashe, 2007;Schaffar et al., 2013). These evasion tactics vary depending on the number of boats and the approach distance (Williams et al., 2009;Schaffar et al., 2013). ...
... It has been shown that humpback whales (Megaptera novaeangliae) change their trajectory continuously when boats are close (Schaffar et al., 2013). It has been shown that the displacement trajectory of orcas (Orcinus orca) becomes more linear as the number of boats increases, indicating that the evasion tactic (increase in reorientation) may not be effective in the presence of a larger number of boats (Williams and Ashe, 2007;Williams et al., 2009). If evasive tactics are not effective, cetaceans must use strategies that are more energetically costly (Morete et al., 2007;Sprogis et al., 2020a,b), such as an increase in the velocity of displacement in the presence of boats Sprogis et al., 2020b). ...
Whale-watching (WW) is an activity which has been increasing worldwide due to the great interest of tourists and the economic benefits it provides to local communities. However, it has been reported that this activity affects the behavioral patterns of some cetaceans, although for some species such as the fin whale (Balaenoptera physalus) this has not been extensively studied. To identify the effects of WW on the behavioral patterns of this species, we studied its traveling and resting behaviors in a locality of north-central Chile from 2015 to 2018. Using a theodolite, we calculated the response variables of swim speed, directness index, and reorientation for each behavior. We used the number of WW boats and the WW scenarios of "before", "during", and "after" the presence of boats as possible factors to explain the differences in the response variables of the whales, along with the factors of year, month, group size, and distance from the observation point. Reorientation increased significantly and the directness index decreased significantly for both traveling and resting behaviors from "before" to "during" WW scenarios, indicating more erratic and sinuous movements in the presence of boats. These changes in movement patterns are a commonly reported evasion response of cetaceans to the presence of WW boats. For traveling behavior, the swimming speed significantly increased, and trends showed increased reorientation and a decrease in the directness index in the "after" WW scenario, which suggests perturbation of the Frontiers in Marine Science | www.frontiersin.org 1 March 2021 | Volume 8 | Article 623954 Santos-Carvallo et al. Fin Whale Responses to Whale-Watching whales potentially associated with the speed and the direction in which the boats left. During resting behavior, the trajectories of the fin whales became straighter (decrease in reorientation) as the number of boats increased, thus evasion (more erratic and sinuous movements) is a behavior used less by fin whales as the number of boats increases. Notwithstanding the fact that tourism development in the study area is small in scale, we found that WW generates adverse effects that are reflected in changes in the whales' movement patterns. This kind of information is valuable to the adjustment and/or design of management strategies for the species, which is fundamental for WW to continue to be a sustainable activity.
... Boat traffic has been shown to affect the short-term behavior (Williams et al. 2002a, b;Williams and Ashe 2007;Noren et al. 2009;Williams et al. 2009a) and activity budgetsincluding feeding activities (Williams et al. 2006;Lusseau et al. 2009) -of northern and southern resident killer whales. Periods of reduced prey availability have been linked to periods of high adult mortality (Ford et al. 2010) and reduced reproduction (Ward et al. 2009) in resident killer whales. ...
... Secondly, avoidance response was stronger as boats approached whales more closely (and received noise level tends to increase) (Williams et al. 2002a;Williams et al. 2009a). Third, the observed evasive tactic changed as the number of vessel increased to three or more vessels (Williams and Ashe 2007). In each of these studies, nonmotorized vessels including kayaks were included in boat counts. ...
... This would allow researchers to view whales in the absence of boats, then experimentally manipulate boat traffic of different vessel types, and measure the response. This approach has been successful in Robson Bight (Michael Bigg) Ecological Reserve (RBMBER) (Williams et al. 2002a(Williams et al. , 2002bWilliams and Ashe 2007). The precautionary principle would strongly suggest that an MPA should apply to all vessels until evidence is available to give any vessel type an exemption. ...
Humans seeking to observe wildlife in their natural habitat can disrupt the activity of the individuals they target. One hypothesis is that behavioral reactions emerge from animals perceiving humans as a potential risk. If it was the case we expect the avoidance tactics to be mediated to account for the difference in risk factors different platforms might present. We examined whether behavioral responses of northern resident killer whales differed between powerboats and kayaks to test this prediction. Killer whales responded to kayaks by increasing their probability to switch to travelling activity more often than during control (no-boat) conditions. As a result, killer whales spent significantly more time traveling when in the presence of kayaks than they did under control, no-boat conditions (11% increase in time spent travelling). Consistent with previous studies examining the effects of powerboats, killer whales significantly reduced overall time spent feeding in the presence of kayaks and powerboats (30% decrease in the time spent feeding). Overall, we show that killer whales have different avoidance tactics to deal with the two types of vessels (motorized or not) and that they will try to outpace kayaks because those cannot follow them. The presence of motorized vessels, particularly vessels targeting whales, decreased the odds that killer whales were feeding (odds ratio: 0.70, 95% CI: 0.62-0.79). The presence of kayaks increased the odds that killer whales were traveling (odds ratio: 1.13, 95% CI: 1.001-1.280). Silent vessels (kayaks) can therefore elicit avoidance tactics like boats that have an acoustic signature do. Such findings are consistent with observed risk avoidance strategies in long-lived mammals. These avoidance strategies have different energetic consequences. While both kayaks and powerboats affect both feeding and travelling behavior, kayaks tend to increase killer whales' energetic demand while powerboats tend to decrease their opportunities to acquire energy.
... The behaviour of some dolphin species shifted from resting to milling or travelling when the number of boats around the school increased (Lusseau 2003;Constantine et al. 2004;Christiansen et al. 2010). The presence of tour boats has been observed to alter the target cetacean"s line of travel (Williams & Ashe 2007) to the point that the animals dived to avoid the boats (Schaffar et al. 2009). As a result, experts have become increasingly vocal about the need to regulate whale and dolphin watching activities (Orams 2000;Brownell & Oosthuizen 2004;Constantine et al. 2004;Corkeron 2004;IWC 2009). ...
... This approach is conducted to measure the effect(s) of a treatment (e.g., X number of tour boats or Y interaction times) on the local cetacean populations (Bejder & Samuels 2003). Williams & Ashe (2007) used this design to examine the responses of Orcinus orca to boats in British Columbia using experimental manipulations. They found that the killer whales showed evasive movements in the presence of a certain number of tour boats. ...
... However, when there were more than three tour boats, the whales" travel paths became more direct. Williams & Ashe (2007) attributed this change of behaviour to non-linear relationships between variables, e.g., the whale"s lack of horizontal escape space due to an excessive numbers of boats. Nowacek et al. (2001) compared the inter-breathing interval of Florida Tursiops truncatus with and without tour boats (i.e., the boats were >100m away). ...
This research studied dolphin watching in Lovina, North Bali, Indonesia in the theoretical context of quadruple bottomline sustainability and the prism of sustainability to investigate the biological, social, economic and managerial elements of the sustainability of the industry.
This industry depends on predictable access to coastal dolphins, particularly dwarf spinner dolphins (Stenella longirostris roseiventris). Dolphin watching tourism at Lovina began in the late 1980s when local artisanal fishers formed self-regulating cooperatives. Up to 179 dedicated traditional fishing vessels (jukungs) are available to take passengers to watch the cetaceans that are predictably found 3-4 km from the shore. An average of 34.5 tour boats from four dolphin associations operated for up to three hours each morning in Lovina during my data collection period (2007 to 2009), with up to about 100 tour boats per day searching for the animals during the high tourist visitation season. A school of dolphins could be surrounded by up to 83 boats (median 15.35). In an encounter, the number of boats generally outnumbered the number of dolphins (median spinner-to-boat ratio = 0.8:1).
The dolphins generally surfaced only briefly (<2 minutes) and were almost always travelling when first sighted in the mornings. Most dolphin schools were surrounded by boats, making the establishment of control units impossible. Many boats were driven erratically, making it very difficult to measure the impact of this industry on the local dolphin population. However, examination of the boatmen’s conduct indicated that the operations at Lovina did not conform to accepted international norms. Most boatmen attempted to get as close as possible to the dolphins (generally much closer than the recommended 50m minimum approach distance stipulated in Australian and many other national-level regulations). During 175 scan sampling efforts over 36 days I identified 64 individual boats that displayed ‘behaviours of concern’ at least once.
The industry generally attracts tertiary-educated international visitors. In 2007-2009, two-thirds of the dolphin tourists came from Western countries; the rest were from Asia. Average tourist satisfaction was low to medium (7.1 on a scale of 1-10). While there was no significant difference between the average satisfaction of Western and Asian tourists, the associated variables differed. The satisfaction of Western tourists was associated with encounter management, their preferred number of surrounding boats and the number of dolphins seen. Encounter management was the only variable associated with the satisfaction of Asian tourists. Western respondents disliked the mismanagement of the dolphin tour; they considered that too many boats exhibited behaviours of concern and that the approach distances were too close. Satisfaction was positively associated with the willingness of tourists to recommend the tour to others. Western respondents who felt neutral to very comfortable with the way their boatmen managed the dolphin encounters were more likely to promote the tour. Thus the low to medium satisfaction levels of Western dolphin tourists threatened to bring negative publicity for Lovina dolphin tourism from word of mouth and other sources.
In 2007-2009, the industry attracted at least 37,000 overnight visitors per annum (~60% of Lovina’s overnight tourists) who contributed up to USD 9.5 million p.a. in total direct expenditures (i.e., tickets, accommodation, meals, transportation, communication and souvenirs). At least 46% of the total direct expenditure was attributable to the dolphin watching tourism. The boatmen enjoyed an above average income but trip fees constituted only 3% of the total income generated by dolphin watching tourism; the remainder was spent on local businesses e.g., accommodation, restaurant and transport, which are the most substantial beneficiaries. As a consequence of the economic importance of this industry to the boatmen and the villages, it is important for the boatmen to improve their dolphin encounter management to meet the expectations of the highly educated international visitors. Because the industry also brings a significant economic contribution to other business sectors, the sustainability of the overall industry is very important to them. The hoteliers, restaurateurs and travel agents should also be included in the future management strategies in Lovina, including assisting the boatmen in improving their service.
Interviews with the boatmen confirmed that the industry was essentially unregulated. The boatmen were concerned about the industry’s long-term sustainability, especially their encounter management practices and other operational issues such as garbage and safety. The boatmen agreed in-principle to improve their encounter management by: 1) turning off the engine/lifting the propeller, 2) keeping the boat’s distance from the dolphins and 3) avoiding cutting across the dolphin’s route. However, they were reluctant to limit the fleet size, very likely due to the economic importance of the industry to their livelihoods.
Reduction of the boat crowding in Lovina is important from the perspectives of animal welfare and tourist satisfaction. Replacing the jukungs with larger boats to reduce the number of boats is considered impractical from funding and organisational viewpoints. This idea is also undesirable from the cultural viewpoint and because it might reduce tourist experience. Establishing an agreed minimum approach distance would be an indirect approach to managing the number of boats and viewing duration. This strategy could be achieved by establishing an agreed maximum number of boats (15 is suggested) in a 50m perimeter for an agreed viewing time for safety, comfort and tourist experience.
The in-principle agreements established by the Lovina boatmen have not yet been implemented. Training programs should be offered to the boatmen, including how to estimate approach distance and speed limit and appropriate methods to approach the animals. Once training is completed, discussions should be directed to add more management aspects to the codes of practice (e.g., speed limitation, encounter fleet size and approach behaviours) and to codify the codes of practice e.g., by including the guideline in the local Balinese awig-awig (customary norms/rules). The guidelines could then be adopted at regency and national levels.
Several challenges and opportunities must be considered in managing the Lovina dolphin watching industry in a sustainable manner. Working with the local community in Bali requires an appreciation of the characteristics of the people of Bali, including its patriarchal nature, the traditional codification system or awig-awig and the local sustainability framework (‘Tri Hita Karana’). Bali was usually conceived as a cultural tourism destination. The inclusion of cultural elements (e.g., the daily life of a dolphin boatman and the construction, repair and maintenance of the traditional outriggered wooden canoe or ‘jukung’) can enhance the tourist experience, increase the length of stay and reduce the focus on the dolphins themselves, which in turn could benefit the promotion of the dolphin tour and the local economy.
The biological sustainability of the dolphin watching industry in Lovina is questionable and most tourists are not very satisfied. However, because the industry is very valuable to the boatmen and the villages, the long term sustainability, viability and health of the dolphins are a priority to a socially and economically sustainable industry. Consequently, the industry needs to be sustainably managed with the consent and involvement of all boatmen and other supporting stakeholders. Despite the current concerns over its sustainability, the Lovina dolphin watching industry could potentially become an exemplar of community-based tourism in a developing country that is successfully co-managed from multiple perspectives. The four elements of sustainability used in this research provided valuable insights into the industry and should be applicable to other studies designed to inform sustainable marine wildlife tourism in developing countries.
... However, differences in exposure conditions across observations were probably responsible for an important part of this variability. For example, the number and distance of whale watching vessels are known to influence the severity of behavioral responses in a number of cetaceans (Williams and Ashe, 2007;Stamation et al., 2010;Steckenreuter et al., 2011;Villagra et al., 2021). Here, because of the way observations were conducted and limitations in sample size, we could not account for either factor in the analysis. ...
... Here, because of the way observations were conducted and limitations in sample size, we could not account for either factor in the analysis. Converting the full range of exposure conditions into a binary variable (i.e., presence/absence of whale watching vessels) and contrasting the average response of whales, may have obscured real responses and weakened the detectability of significant effects (Williams and Ashe, 2007). Additionally, our ability to detect changes in behavior may have also been affected by potential cumulative effects of disturbance, if previous exposure to whale watching vessels conditioned whale's response during observed exposure periods, or their behavior during periods of non-exposure. ...
Disturbance from whale watching can induce a wide range of behavioral responses in cetaceans, some of which can affect their energetic balance and, ultimately, their long-term fitness. However, assessing disturbance effects on deep-diving cetaceans remains challenging, as the majority of their activities occurs underwater and are difficult to monitor from surface observations. To surpass this limitation, we attached high-resolution multi-sensor tags (DTAGs) on 24 sperm whales (Physeter macrocephalus) off the Azores, an area of intense whale watching, to evaluate changes in movement and acoustic parameters related to foraging effort and dives, locomotion effort, and non-foraging behavior. These parameters were compared between periods of exposure and non-exposure to whale watching vessels, using linear mixed-effect models to assess the presence of short-term effects, accounting for individual differences in behavior. We found no significant changes in foraging effort (number of buzzes, bottom phase depth, proportion of search and foraging phases) and overall dive behavior (dive duration, proportion of dive phases, and descending or ascending pitch) between non exposure and exposure periods. In contrast, variation in body pitch during non-foraging periods increased during exposure but not variation in body roll. Taken together, these results suggest increased movements during resting activity, which may carry energetic costs to whales and impact their health. Vertical velocity during ascents was also significantly higher in response to vessel exposure, suggesting that sperm whales increased the frequency of fluke strokes, which was consistent with a higher Overall Dynamic Body Acceleration (ODBA) during ascents, incurring in higher energy expenditure. If the detected changes are repeated across multiple exposures, they might affect the individual’s energetic budget, and consequently their fitness. Our study contributes to a better understanding of the short-term behavioral responses of sperm whales to whale watching vessels and highlights the need for further studies examining the potential consequences from repeated disturbance to individuals.
... For this study, vessels were considered "present" when traveling within 100m of the focal individual/group. The distance threshold encompasses the NMFS suggested distance of at least 45m and extended to 100m (Williams and Ashe, 2007) to include dolphins that were actively following shrimp trawlers (hereafter in this chapter 'trawlers'). A theodolite can determine the position of only one target at a time; therefore, to calculate accurate distances of vessels from dolphins, vessel positions were interpolated post hoc relative to binned dolphin positions and times. ...
... Several vessel distance thresholds (i.e., distance in which vessels were considered "present") were evaluated during the exploratory analysis phase, including 500m, 300m, and 100m, to select an appropriate threshold. Variation emerged for the 100m threshold only, and this distance has been established in other odontocete literature involving effects of human activity (Constantine, 2001;Weir et al., 2010;Williams and Ashe, 2007) and is the same threshold used in Chapter II of this dissertation. The "no vessel" control category included segments in which no moving vessels were within 100m during, and for at least 10 minutes prior to, the dolphin focal follow. ...
This dissertation contributes to our understanding of anthropogenic effects on wildlife, a central question in the growing field of conservation behavior. I present three case studies of coastal delphinid species in diverse ecosystems with varied human pressures. I examine how 1) common bottlenose dolphins (Tursiops truncatus) in a narrow congested waterway respond to heavy vessel traffic, 2) Indo-Pacific humpback dolphins (Sousa chinensis) respond to chronic maritime construction and associated vessel activity, and 3) dusky dolphins (Lagenorhynchus obscurus) use distinct patches within a bay that supports shellfish aquaculture.
In each study, group focal follows were conducted using non-invasive shore-based theodolite tracking. Data collection included behavioral states, movement patterns and habitat-use patterns. Metrics to evaluate alterations in movement patterns included swimming speed, reorientation rate, and linearity. Data to evaluate alterations in habitat-use included behavioral activity states and track duration among habitat patches. Multivariate generalized additive models identified significant explanatory variables.
Dolphin movement and habitat-use patterns were good indicators of response to human activity across diverse species and ecosystems. Bottlenose dolphins avoided tour boats and were attracted to commercial trawlers that may facilitate prey accessibility. Current voluntary dolphin-viewing recommendations do not protect dolphins from behavioral harassment, but dolphins did not abandon the area, which may reflect a lack of ecologically similar habitat nearby. Humpback dolphins avoided areas near chronic construction activity during the day, but some returned at night when human activity decreased. Dusky dolphins used defined patches within the bay in different ways. Mid-bay and nearshore patches reflect areas that may yield greater benefits relative to prey ball herding opportunities, whereas patches near mussel farms reflect areas that may yield greater benefits relative to non-prey ball foraging opportunities.
Flexibility in foraging tactics occurred across study sites and species, and allows dolphins to adjust to fluctuating environments with ephemeral and patchily distributed prey. Behaviors are likely influenced by human activity, prey characteristics, and accessibility to alternate habitats that support prey. Integration of data on prey characteristics (e.g., fish species, abundance, and distribution) in future research will enhance our understanding of factors influencing dolphin behavior in these dynamic systems.
... However, vessels used in the cetacean-watch industry provide frequent and relatively inexpensive access to cetaceans, and the ability to obtain many observations of cetacean-tourist interactions. For example, commercial tour vessels were used to good effect to study commercial swim-with-dolphin operations (Constantine, 2001), and in controlled approach experiments, combined with observations made from a land-based theodolite, to record the behaviours of the target cetaceans when approached by the cetacean-watch vessel (Williams and Ashe, 2007). In addition, the presence of researchers on a cetacean-watch vessel allows accurate and up-to-date knowledge to be communicated to tourists, and social science researchers can also obtain data on the cetacean-watching experience and tourist expectations. ...
... Possible effects must be evaluated with any changes in the cetacean populations due to natural phenomena (Lusseau and Higham, 2004), and as a consequence, evaluating whether cetacean-watch operations are having a biologically significant effect on target cetacean populations is challenging. (Williams and Ashe, 2007). In New Zealand, the resting behaviour of bottlenose dolphins decreased as the number of boats increased in the Bay of Islands (Constantine et al., 2004) and in Milford Sound . ...
Coastal dolphin populations are exposed to non-consumptive human activities that can pose conservation challenges. Consequently, effective management strategies, using rigorous scientific assessments of exposed populations, are needed to mitigate any potential negative impacts of these activities. To inform management decisions for the conservation of the Hawaii Island spinner dolphin (Stenella longirostris) stock, I: (i) estimated abundance and survival rates; (ii) measured the effectiveness of various sampling scenarios to detect changes in abundance; (iii) identified important spinner dolphin resting habitats; and (iv) measured cumulative exposure to human activities. Between September 2010 and March 2013, boat-based and land-based sampling was undertaken to collect dolphin photo-identification, group behaviour and acoustic data from both inside and outside four important spinner dolphin resting bays on the Kona Coast of Hawaii Island. Between years, independent survival rate estimates were similar (0.97 ± 0.05 SE), and abundance estimates of 631 (95% CI 524-761) and 668 (95% CI 556-801; CV =0.09) were very consistent. At this precision, and with 95% power and a monitoring interval of three years, a 5% change in abundance would not be detected for 12 years. I documented that should resting spinner dolphins be displaced from resting bays, they are unlikely to engage in rest behaviour elsewhere. When resting inside bays, dolphins were most likely to rest between 10:00-14:00, and over sandy substrates. Individual spinner dolphins spent between 49.5% and 69.4% of daytime resting (mean = 61.7%). Dolphins were chronically and repeatedly exposed to human activities during daytime hours (> 82% of time), with a median duration of only ten min between interactions. The short interval between interactions may prevent recovery from disturbance and deprive individuals of rest and change their sleep state from “deep” to “light”. Rest deprivation and the disruption of sleep can lead to impaired cognitive abilities and ultimately effect population viability. These data provide a firm baseline for urgent consideration by managers to evaluate the risks to the spinner dolphins of Hawaii Island, potential pathways for mitigating human interactions and ways to measure the success of management interventions.
... Resident killer whales also exhibit changes in vessel avoidance behaviour (i.e. swim speed and path tortuosity), and a reduction in foraging effort, based on the number of vessels present and vessel proximity (Erbe, 2002;Lusseau et al., 2009;Williams and Ashe, 2007). The classification of wildlifeviewing vessel behaviour can be used to estimate the number of AIS enabled vessels at a single wildlife-viewing event, which, when paired with confirmed cetacean sightings, may support analyses of behavioural changes to multivessel exposure, such as modelling humpback whale energy expenditure over time. ...
A continued rise in global ocean vessel activity has led to growing concerns for the health of whales around the world. Of particular interest is the increase in recreation vessels, including those related to whale-watching activities. However, there is an absence of established procedures to identify vessels engaged in whale-watching, thus limiting the ability to quantify whale-watching impacts on whales. This study evaluates three computational classification models and their ability to utilize Automatic Identification System (AIS) data to describe wildlife-viewing vessel behaviour. These models include a density-based spatial clustering application with noise (DBSCAN), a hidden Markov model (HMM), and logistic regression (LR), all of which have been previously used to classify vessel behaviour in industries, such as fishing, shipping, and marine security. The results of each model's classification were validated against observed whale sighting data using statistical performance and accuracy metrics. The findings suggest that all three classification models sufficiently detect wildlife-viewing behaviour, but the HMM and LR had preferable performance metrics compared to DBSCAN. Further, although LR provides an informative glance at which AIS variables are most important to detecting wildlife-viewing events, the HMM has comparable performance metrics and requires less data processing. Therefore, this study recommends the use of HMM due to its computational efficiency and because it provides an accurate classification of wildlife-viewing behaviour for whale-watching vessels. The results of this study can be used to support policy decisions, monitor regulation compliance, and inform marine conservation initiatives.
... In 11 of these studies, marine mammals reoriented or completely changed their swimming paths or patterns. Changes in movement or behavior in response to human presence and noise are known to elevate energy loss and consequently impact fitness [64]. For example, in minke whales (Balaenoptera acutorostrata) and killer whales subjected to increased boat traffic, both species spent more time traveling and less time foraging, resulting in an estimated 42% and 18% decrease in energy intake for the respective species [65,66]. ...
Humans have been altering wildlife habitatsHabitat and wildlife behavior worldwide at an accelerated pace in recent decades. While it is well-understood how human-induced behavioral changes affect infectious disease risk in terrestrial wildlife, less is known in marine life. Here we examine this link in marine mammalMarine mammals populations by (1) conducting a systematic literature review to determine how human disturbancesDisturbance change marine mammal behavior in ways that can impact disease spread, and (2) using a mathematical modeling framework to examine how these behavioral changes might influence potential epidemics. Human disturbances can influence marine mammal behavior in ways that increase their exposure and susceptibility to pathogens, as well as their infectivity, or ability to effectively shed pathogens and infect conspecifics. When these changes to exposure, susceptibility, and infectivity are applied in four different marine mammal case studies (California sea lionsSea lion, Zalophuscalifornianus; Australian humpback dolphinsHumpback dolphin, Australian, Sousa sahulensisSousa sahulensis; killer whalesKiller whale, Orcinus orcaOrcinus orca; Indo-Pacific bottlenose dolphinsBottlenose dolphin, Indo-Pacific, Tursiops aduncusTursiops aduncus), epidemics are predicted to be larger and more likely to occur. Considering the rate at which human disturbanceDisturbance is increasing in the marine environmentEnvironment and the large number of marine mammal species and populations that are endangeredEndangered or on the verge of extinctionExtinction, we advocate for the careful consideration of the direct and indirect impact of human disturbance on marine mammalMarine mammalshealthHealth.
... Many of the dolphins in the study area are highly resident and have small home ranges (Michalec, 2019) and, as a result, an individual dolphin may be involved in HI encounters repeatedly throughout each day, leading to overlapping encounters with multiple vessels present. Williams and Ashe (2007) provided experimental evidence that the number of vessels present influences avoidance behaviors for male killer whales. The prevalence of multiple-vessel and overlapping interactions is also troubling from the acoustic perspective. ...
Human interaction (HI) is known to disturb cetaceans. Regional wildlife interaction guidelines exist to mitigate harmful impacts, but the efficacy of these guidelines is understudied. HI with bottlenose dolphins was documented opportunistically in Tampa Bay from 2009 to 2018. Vessel compliance to the guidelines was low with 80% of encounters being non-compliant. HI was observed in 33% of days in the field and in 22% of dolphin sightings. Poisson regression identified vessel type as a strong key factor related to compliance, with faster more maneuverable boats more likely to be non-compliant. Additionally, HI involved recreational vessels much more frequently than tourism vessels. These results likely underestimate true HI rates because of sampling limitations. Researchers should opportunistically document HI including vessel characteristics and vessel behavior to help quantify compliance. When developing HI guidelines and their promotion, managers should carefully consider which stakeholders engage in HI to best direct resources to that audience.
... Marine vessels are known to cause significant behavioral reactions in whales and several studies have recorded effects of whale-watching vessels on short-term behavioral responses of whales, including changes in surface behavior (Corkeron, 1995;Noren et al., 2009;Stamation et al., 2010;Williams et al., 2009), acoustic (Foote et al., 2004;Richter et al., 2006;Sousa-Lima & Clark, 2008), and swimming behavior (Stamation et al., 2010;Williams & Ashe, 2007;Williams et al., 2002Williams et al., , 2009. Some species of whales seem to be more sensitive to moving boats. ...
Reactions of southern right whales (SRWs) related to whale-watching boats have been reported in Patagonia, but there are no quantitative data showing how these whales react to boats not preforming whale-watching trips. The objective of this study was to investigate the reaction of SRWs to transiting vessels. Data were collected off the coast of Puerto Madryn city, and were analyzed by means of cumulative logit models, using the whales' intensity of behavioral response as an ordinal dependent variable. During the experimental approaches of a research vessel, we found that the response of SRWs differed depending on the number of whales present. The results of this study show that the probability of response to transiting vessels is low, unless there are only a few whales in a group, or it is a mating group. This response is different from that of an approaching whale-watching vessel. In this study, the lack of reaction of whales to the research vessel suggests that whales would not consider it as a threat. This study represents an important piece of information for the conservation of southern right whales.
... Several vessel distance thresholds (i.e., distance in which vessels were considered "present") were evaluated during the exploratory analysis phase, including 500, 300, and 100 m, to select an appropriate threshold. Variation emerged for the 100 m threshold only, and this distance has been established in other odontocete literature involving effects of human activity (Constantine, 2001;Williams and Ashe, 2007;Weir et al., 2010). The "no vessel" control category included segments in which no moving vessels were within 100 m during, and for at least 10 min prior to, the dolphin tracking session. ...
Construction-related loss of habitat, degradation of existing habitat, noise pollution, and vessel activity are growing issues for Indo-Pacific humpback dolphins (Sousa chinensis) that occur in the shallow, near-shore, highly industrialized waters off Lantau Island, Hong Kong. We studied the occurrence of dolphins in discrete locations, fine-scale movement patterns, and dolphin behavioral activity states. Potential explanatory variables varied and included year, season, time of day, dolphin group size and behavioral activity state, proximity to construction activity, and vessel type and number. Land-based observations and theodolite tracking of dolphins and vessels were conducted from seven locations to the north of Lantau Island, Hong Kong, and marine construction activities near survey sites were identified. A total of 636 groups of dolphins were recorded, totaling 150.91 h of tracking, from 405 days of observation effort. Hurdle models were used to analyze dolphin occurrence, multivariate generalized additive models were used to analyze fine-scale movement patterns, and log-likelihood ratio and binomial z score post hoc tests were used to analyze behavioral activity states. Dolphin occurrence was lower in historically important areas near long-term, low-intensity construction activity, and dolphin swimming speed was higher in response to vessel presence. Overall, foraging and traveling were the most frequently observed behavioral activity states and resting behavior was observed off only one location that was not in proximity to construction activities. Temporal overlap in adjacent marine construction areas may displace animals for extended periods and nearby ecologically similar habitats should be identified and designated as marine protected areas to mitigate effects of such disturbance.
... However, each additional boat led to a significant 7% increase of the swimming speed, and consequently a 10% COT reduction. Similarly, a high number of whale-watching boats at less than 400 m induced killer whales to follow a more sinuous swimming path (Williams et al., 2002;Williams and Ashe, 2007) together with an increase in their swimming speed (Williams et al., 2002). Arguably a higher number of boats could result in a higher noise level. ...
Interactions between whale-watching boats and cetaceans can lead to changes in their behavior. From a management perspective, it is important to understand how this type of disturbance can be translated into physiological effects, such as changes in their energetic metabolism. Humpback whales (Megaptera novaeangliae) typically do not feed while in breeding grounds, thus they depend on finite energy reserves. The effect of whale-watching boats on the energetic metabolism of humpback whales, in the breeding ground of northern Peru (4 • 10 35 S, 81 • 08 03 W) was evaluated. Groups of humpback whales were tracked from land, under the following scenarios: with, without, and before-during-after the presence of whale-watching boats. Mass-specific cost of transport (COT) was used as a proxy of energetic efficiency and calculated from swimming speed and breath frequency estimations. No differences were detected in breath frequency, swimming speed, and COT when comparing whales with and without boats. However, in the presence of boats, swim speed increased, and COT decreased as the number of boats increased. Exponential increment in breathing frequency at higher swimming speed was not detected. The absence of swimming speeds beyond the assumed optimal range suggested no shifts into metabolic inefficiency. Our results suggest optimal swimming speed between 2 and 4.05 m/s, representing COT values between 0.020 and 0.041 J × (kg × m) −1. In light of our results, we encourage the implementation of regulations of the activity, particularly limiting the number of boats interacting with the same group of humpback whales.
... In 11 of these studies, marine mammals reoriented or completely changed their swimming paths or patterns. Changes in movement or behavior in response to human presence and noise are known to elevate energy loss and consequently impact fitness [64]. For example, in minke whales (Balaenoptera acutorostrata) and killer whales subjected to increased boat traffic, both species spent more time traveling and less time foraging, resulting in an estimated 42% and 18% decrease in energy intake for the respective species [65,66]. ...
Humans have been altering wildlife habitats and wildlife behavior worldwide at an accelerated pace in recent decades. While it is well-understood how human-induced behavioral changes affect infectious disease risk in terrestrial wildlife, less is known in marine life. Here we examine this link in marine mammal populations by (1) conducting a systematic literature review to determine how human disturbances change marine mammal behavior in ways that can impact disease spread, and (2) examining how these behavioral changes might influence potential epidemics using a mathematical modeling framework. We find that human disturbances can influence marine mammal behavior in a way that increases their exposure and susceptibility to pathogens, as well as their infectivity, or ability to effectively shed pathogens and infect conspecifics. When these changes to exposure, susceptibility, and infectivity are applied in four different marine mammal case studies, epidemics are predicted to be larger and more likely to occur. Considering the rate at which human disturbance is increasing in the marine environment, and the large number of marine mammal species that are endangered oron the verge of extinction, we advocate for the careful consideration of the direct and indirect impact of human disturbance on marine mammal health.
... Although no studies have yet focused on vessel impacts on Bigg's killer whales, residents have been shown to alter their swimming behavior and cease feeding when approached by boats (Noren, Johnson, Rehder, & Larson, 2009;Williams, Bain, Smith, & Lusseau, 2009;Williams & Ashe, 2007;Williams & Noren, 2009); as well as increase their call amplitude to compensate for acoustic masking from vessel noise (Holt, Noren, Veirs, Emmons, & Veirs, 2008). A recent cumulative effects analysis showed that resident killer whales secrete stress hormones primarily due to a decrease in prey abundance, however it appears stress was exacerbated due to chronic exposure to vessels (Ayers et al., 2012). ...
The social lives of animals are defined by group dynamics based on the nature and strength of associations and movements between individuals, often resulting in highly complex and interconnected social networks. However, understanding of how environmental variables may shape this structure is poorly understood. Within the inland waters of Washington State and southern Vancouver Island, British Columbia, mammal- eating Bigg’s (transient) killer whales occur in relatively small, but stable social groups. Group size and occurrence in recent years has increased, coinciding with a growing whale watching industry. Given the central importance of the social network within killer whale population dynamics, such as the maintenance of cooperation and cultural transmission of information, shifts in social network structure caused by environmental processes may have significant ecological and evolutionary consequences. Thus, it is reasonable to assume that the increased presence of Bigg’s killer whales within the Salish Sea leaves them susceptible to the various and growing anthropogenic pressures within this area. Utilizing a long-term data set (1987-2015), the objectives of this doctoral study are to: (1) identify the level(s) of preferred associations and social differentiation within Bigg’s societies relative to foraging specializations; (2) re-evaluate and compare historical measures and persistence of Bigg’s sociality, including demographic influences
ii
and dispersion patterns; and, (3) assess the extent to which individual sociality can predict received vessel traffic levels, as well as other variables driving targeted whale watching. The results of this work will better clarify the social dynamics and population structure of Bigg’s killer whales and will thus inform on proper management of this conservation unit. Likewise, the combined evaluation of social dynamics and anthropogenic pressures (vessel traffic) experienced by this population can provide key information that may enable managers to implement proper measures to mitigate anthropogenic impacts. Finally, the results of this analysis will serve as a platform for further evaluating the predator-prey dynamics of Bigg’s killer whale stocks that are central to the Salish Sea ecosystem.
... For this study, vessels were considered "present" when traveling within 100m of the focal individual/group. The distance threshold encompasses the NMFS suggested distance of at least 45m and extended to 100m [69] to include dolphins that were actively following behind shrimp trawlers (hereafter 'trawlers'). The "no vessel" category included dolphin tracks for which no moving vessels were present during and for at least 10 min prior to the focal follow to reduce the potential that dolphin movement was influenced by recent vessel presence. ...
The Galveston Ship Channel (GSC) is a narrow, congested waterway that supports large-scale shipping, commercial fishing, dolphin tourism, and recreation. Human activity and common bottlenose dolphins (Tursiops truncatus) converge in the GSC with potentially negative consequences on the dolphins. Elevated land-based tracking and behavioral observation of dolphins and vessels were conducted along the GSC in June-August 2013 using a digital theodolite. Positional information was used to calculate dolphin movement patterns and proximity to vessels. Log-likelihood ratio and Chi-square contingency tests were used to assess behavioral states, and generalized additive models were used to analyze movement patterns (i.e., swimming speed, reorientation rate, and linearity) relative to endogenous and exogenous factors and vessel presence. Dolphins regularly use the GSC to forage (57% of observed behavioral states) and socialize (27%), and it is not a travel corridor for accessing other favorable sites (traveling = 5%). Dolphin behavior varied significantly based on time of day, group size, calf presence, and general boat presence. When boats were present, the proportion of time dolphins spent socializing and foraging was significantly less than expected by chance. Swimming speeds increased significantly in the presence of small recreational boats, dolphin-watching tour boats, shrimp trawlers, and when tour boats and shrimp trawlers were both present. Reorientation rate increased significantly in the presence of tour boats and trawlers. Dolphin behavioral responses to vessel presence may result in decreased energy consumption due to disrupted foraging activity. Without proper management, the observed behavioral changes may be detrimental to individuals within this population in the short term, with potential long-term consequences to health and survivorship.
... size; engine power, type, and position; behaviour; speed) (Constantine, Brunton, & Dennis, 2004;Stevens & Boness, 2003). Future effort should also investigate whether a numerical vessel-crowding threshold (Williams & Ashe, 2007) or a distance threshold (Schaffar et al., 2013) exists. ...
• Whale watching can affect cetacean behaviour, and can in some cases lead to long‐term negative effects on survival and reproduction.
• The waters of Juneau (Alaska) represent a summer feeding ground for the Central North Pacific stock of humpback whales, Megaptera novaeangliae (Borowski, 1781). The recent dramatic expansion of the local whale‐watching industry has raised concerns over the potential negative impact of such activity on the whales.
• The aim of this study was to understand the impact of whale‐watching vessels on humpback whale behaviour in Juneau. From June to September 2015, land‐based observations were conducted to record whale behaviour in the presence and absence of vessels.
• Markov chains and model simulations showed that the presence of vessels was not associated with a reduction in the time spent feeding. Whales exhibited more surface‐active behaviour and travelled less in the presence of vessels.
• The lack of an overt response of feeding whales to whale‐watching disturbance could result from the importance of the Southeast Alaska study region as a feeding ground, which could make the whales less apt to interrupt feeding under disturbance; however, The high proportion of travelling observed may indicate that the study area represents a travelling corridor between other, localized feeding areas. The increase in surface‐active behaviour may represent a response to vessel presence that could potentially lead to energetic consequences.
• The large number of whale‐watching vessels operating could lead to the increased tolerance of whales towards whale‐watching activities. The lack of responses in this study may suggest that the reactions of whales are context specific, depending on their previous experience with vessels and their foraging behaviour, for example. Subtler negative effects could still occur, however, and a prolonged monitoring programme is required to assess less overt behavioural responses of whales over time.
... With industry partnerships now established, collaborative controlled-exposure experiments using individual vessel types and variable numbers of vessels could be conducted to more closely examine whale response patterns (e.g., Williams and Ashe 2007). Furthermore, we monitored only surface behaviors as metrics of disturbance, yet whales may exhibit responses through physiological traits or subsurface behaviors. ...
... Though 63% of operations were classified as sustainable (i.e., not resulting in the long-term destruction or degradation of utilized wildlife resources), only 18% were found to have made measurable positive contributions to conservation (Krüger, 2005). Moreover, negative impacts on wildlife can be difficult to confirm or predict, as they may not be immediate, obvious, or easily detectable without long-term behavioral or physiological data (Sorice et al., 2003;Williams and Ashe, 2007). While tourism has potential to conserve wildlife, it also has the potential to actively work against conservation by exacerbating human-wildlife conflict or leading to sub-lethal and even lethal consequences for participating animals (Burns and Howard, 2003;Newsome et al., 2015). ...
In recent decades, public interest in apex predators has led to the creation and expansion of predator-focused wildlife tourism. As wildlife tourism has become an increasing topic of study for both social and biological scientists, researchers have debated whether these activities serve conservation goals by providing non-con-sumptive values for wildlife. Discussion of predator tourism requires additional recognition of predator-specific biological and ecological characteristics, consideration of human safety concerns, and mitigation of human-wildlife conflict. By reviewing tourism activities centered on both aquatic and terrestrial predators from diverse taxa (sharks, crocodiles, and big cats), we evaluate the potential benefits and conservation challenges associated with predator tourism. Our review suggests that positive conservation outcomes are possible, but not assured given historical, cultural, and ecological complexities. We explore some of the factors which determine whether tourism contributes to conservation outcomes, including (1) effective protection of animals and habitats, (2) avoidance and mitigation of human-wildlife conflict, (3) quality of associated educational interpretation and outreach, (4) collaboration with local stakeholders, and (5) use of generated funds to advance conservation goals. Our findings suggest tourism is most likely to support predator conservation and/or recovery when the industry has both public and political support and under conditions of effective regulation focused on management , monitoring and enforcement by local, national, and international bodies.
... Table 3. Summary of changes in behavior that may impact energy expenditure and/or acquisition in response to anthropogenic sources (e.g., vessels, sonar, noise) for bottlenose dolphins, killer whales, harbor porpoise, and beaked whales. Miller et al., , 2014 Killer whales Vessel presence, sonar Change in swimming behavior Kruse, 1991;Williams et al., 2002aWilliams et al., , 2002bWilliams and Ashe, 2007;Miller et al., 2012Miller et al., , 2014 Killer whales Vessel presence, sonar ...
Odontocetes respond to vessels and anthropogenic noise by modifying vocal behavior, surface active behaviors, dive patterns, swim speed, direction of travel, and activity budgets. Exposure scenarios and behavioral responses vary across odontocetes. A literature review was conducted to determine relevant sources of disturbance and associated behavioral responses for several odontocete species (bottlenose dolphin, killer whale, harbor porpoise, and beaked whales). The energetic costs of species-specific responses to anthropogenic disturbance were then estimated. The energetic impact varies across species and scenarios as well as by behavioral responses. Overall, the cumulative energetic cost of ephemeral behavioral responses (e.g., performing surface active behaviors, modifying acoustic signals) and modifying swim speeds and activity budgets likely increases daily energy expenditure by ≤4%. In contrast, the reduction in foraging activity in the presence of vessels and/or exposure to sonar has the potential to significantly reduce individuals’ daily energy acquisition. Indeed, across all odontocete species, decreased energy acquisition as a result of reduced foraging undoubtedly has a larger impact on individuals than the increased energy expenditure associated with behavioral modification. This work provides a powerful tool to investigate the biological significance of multiple behavioral responses that are likely to occur in response to anthropogenic disturbance.
... Nonetheless, the biological significance of toothed whale responses to different disturbances remains poorly understood. This is partly due to large differences in the nature and magnitude of the response within and between species [21][22][23] . Furthermore, most toothed whale response studies have reported on movement or diving behaviour of individuals (e.g. ...
Social interactions among animals can influence their response to disturbance. We investigated responses of long-finned pilot whales to killer whale sound playbacks and two anthropogenic sources of disturbance: tagging effort and naval sonar exposure. The acoustic scene and diving behaviour of tagged individuals were recorded along with the social behaviour of their groups. All three disturbance types resulted in larger group sizes, increasing social cohesion during disturbance. However, the nature and magnitude of other responses differed between disturbance types. Tagging effort resulted in a clear increase in synchrony and a tendency to reduce surface logging and to become silent (21% of cases), whereas pilot whales increased surface resting during sonar exposure. Killer whale sounds elicited increased calling rates and the aggregation of multiple groups, which approached the sound source together. This behaviour appears to represent a mobbing response, a likely adaptive social defence against predators or competitors. All observed response-tactics would reduce risk of loss of group coordination, suggesting that, in social pilot whales, this could drive behavioural responses to disturbance. However, the behavioural means used to achieve social coordination depends upon other considerations, which are disturbance-specific.
... At sea, positions have been estimated by using the vertical angle between an object and the horizon (Gordon 2001), from overhead video cameras mounted on tethered airships (Nowacek et al. 2001), and by combining laser range finders with compass bearings measured with a GPS (Cure et al. 2012). Some approaches to monitoring marine animals from land can use theodolites, which measure the horizontal and vertical angles to a target (Bejder et al. 2006;Williams and Ashe 2007), but these instruments require a stable platform and they generally only sample one individual at a time. Thus, new equipment would be helpful for studying fast-moving groups of animals in the field over longer time periods and distances. ...
To maintain the benefits of group membership, social animals need mechanisms to stay together and reunite if separated. This thesis explores the acoustic signals that dolphins use to overcome this challenge and mediate their complex relationships in a dynamic 3D environment. Bottlenose dolphins are the most extensively studied toothed whale, but research on acoustic behavior has been limited by an inability to identify the vocalizing individual or measure inter-animal distances in the wild. This thesis resolves these problems by simultaneously deploying acoustic tags on closely-associated pairs of known animals. These first reported deployments of acoustic tags on dolphins allowed me to characterize temporal patterns of vocal behavior on an individual level, uncovering large variation in vocal rates and inter-call waiting time between animals. Looking more specifically at signature whistles, a type of call often linked to cohesion, I found that when one animal produced its own signature whistle, its partner was more likely to respond with its own whistle. To better evaluate potential cohesion functions for signature whistles, I then modeled the probability of an animal producing a signature whistle at different times during a temporary separation and reunion from its partner. These data suggest that dolphins use signature whistles to signal a motivation to reunite and to confirm identity prior to rejoining their partner. To examine how cohesion is maintained during separations that do not include whistles, I then investigated whether dolphins could keep track of their partners by passively listening to conspecific echolocation clicks. Using a multi-pronged approach, I demonstrated that the passive detection range of echolocation clicks overlaps with the typical separation ranges of Sarasota mother-calf pairs and that the amount of time since an animal was last able to detect a click from its partner helped explain its probability of producing a signature whistle. Finally, this thesis developed a portable stereo camera system to study cohesion in situations where tagging is not possible. Integrating a GPS receiver, an attitude sensor and 3D stereo photogrammetry, the system rapidly positions multiple animals, grounding behavioral observations in quantitative metrics and characterizing fine-scale changes that might otherwise be missed.
... A number of studies have reported behavioral differences in resident killer whales in response to vessel traffic and increased underwater noise levels. These can include more evasive swimming paths, changes in diving rates, increased surface activity (e.g., tail and pectoral fin slapping, breaching, spy hopping), reduced foraging time, increased travel time, and increased calling amplitude (Williams and Ashe 2007, Holt et al. 2009). Such behavioral changes are usually subtle and probably result in minor increased energy expenditures by the whales (e.g., see Holt et al. 2015). ...
Killer whales have been listed as a state endangered species in Washington since 2004. Three main populations known as the southern residents, west coast transients, and offshores occur in the state. While closely similar in appearance, these ecotypes differ in their biology, rarely interact with one another, and do not interbreed despite having largely sympatric year-round distributions ranging from California to Alaska. Southern residents totaled just 81 whales as of July 2015 and are the population of greatest concern. Numbers have been relatively stable since 2001, but remain 17% below their recent peak size recorded in 1995. In addition, the population’s growth rate remains well below the downlisting and delisting goals established in the 2008 federal recovery plan. The southern resident population faces significant potential threats from the reduced availability of chinook salmon, interactions with whale-watching vessels and human-generated marine sound, and factors associated with its small population size, including the recent skewing of births towards males, which will constrain productivity over the next few decades. In contrast, the west coast transient population has shown considerable growth since the 1970s in response to the recovery of its marine mammal prey base, and is now estimated to number more than 500 whales and be near its carrying capacity. Offshore killer whales are estimated at 300 individuals and have a stable population trend. All three populations carry heavy loads of environmental contaminants, face a continuing risk of major oil spills in their ranges, are susceptible to a disease outbreak, and will likely experience the impacts of climate change in the future. For these reasons, it is recommended that killer whales remain listed as a state endangered species in Washington.
... A number of studies have reported behavioral differences in resident killer whales in response to vessel traffic and increased underwater noise levels. These can include more evasive swimming paths, changes in diving rates, increased surface activity (e.g., tail and pectoral fin slapping, breaching, spy hopping), reduced foraging time, increased travel time, and increased calling amplitude (Williams and Ashe 2007, Holt et al. 2009Washington Department of Fish and Wildlife et al. 2009). Such behavioral changes are usually subtle and probably result in minor increased energy expenditures by the whales (e.g., see Holt et al. 2015). ...
Killer whales have been listed as a state endangered species in Washington since 2004. Three main populations known as the southern residents, west coast transients, and offshores occur in the state. While closely similar in appearance, these ecotypes differ in their biology, rarely interact with one another, and do not interbreed despite having largely sympatric year-round distributions ranging from California to Alaska. Southern residents totaled just 81 whales as of July 2015 and are the population of greatest concern. Numbers have been relatively stable since 2001, but remain 17% below their recent peak size recorded in 1995. In addition, the population’s growth rate remains well below the downlisting and delisting goals established in the 2008 federal recovery plan. The southern resident population faces significant potential threats from the reduced availability of chinook salmon, interactions with whale-whaling vessels and marine sound, and factors associated with its small population size, including the recent skewing of births towards males, which will constrain productivity over the next few decades. In contrast, the west coast transient population has shown considerable growth since the 1970s in response to the recovery of its marine mammal prey base, and is now estimated to number more than 500 whales and be near its carrying capacity. Offshore killer whales are estimated at 300 individuals and have a stable population trend. All three populations carry heavy loads of environmental contaminants, face a continuing risk of major oil spills in their ranges, are susceptible to a disease outbreak, and will likely experience the impacts of climate change in the future. For these reasons, it is recommended that killer whales remain listed as a state endangered species in Washington.
... Avoidance of cetaceans to even few small-vessel tourist boats has been documented as a long-term effect, with possible implications for local populations (Bejder et al., 2006). More recent studies confirm substantial changes in cetaceans' behaviour when exposed to boat noise, greater than previously suspected (Williams and Ashe, 2007;Bearzi et al., 2011;Seuront and Cribb, 2011). ...
... In this study, we were able to account for variability in approach speed and maneuverability (by dividing the approach type into Cat1 and Cat2), but the sample size was not large enough to take the length of time of approach into account, nor any difference in behavior between those that were successfully tagged and those that were not. Increased speeds and directional changes in response to approaching vessels have been reported previously in humpback whales (Au and Green 2000, Scheidat et al. 2004, Morete et al. 2007, Alves et al. 2010 and other cetacean species such as bowhead whales (Balaena mysticetus) (Richardson et al. 1985), killer whales (Orcinus orca) (Williams and Ashe 2007), Indo-Pacific bottlenose dolphins (Tursiops aduncus) (Steckenreuter et al. 2011), and fin whales (Jahoda et al. 2003), indicating that our findings are relatively common responses to close approaches by small vessels amongst cetaceans. The use of maneuverability and changes in course by humpback whales to Cat2 approaches are similar to avoidance tactics used by humpback whales against predators, such as killer whales, which they are unable to out-swim (Ford and Reeves 2008). ...
Small research vessels are often used as platforms for tagging activities to collect behavioral data on cetaceans and they have the potential to disturb that group or individual. If this disturbance is ignored, results and conclusions produced by that study could be inaccurate. Here land-based behavioral data of migrating humpback whales (Megaptera novaeangliae) (n = 29) were used to determine the effect of close approaches for tagging by research vessels on their diving, movement and surface behaviors. Groups of whales were tagged, using digital recording tags, by small research vessels, as part of a behavioral response study. In groups that were approached for tagging, temporary changes in movement behaviors during close approaches were found, with subsequent recovery to “pre-approach” levels. In female-calf groups more long-term changes in travel speed were found. Results suggest that, although close approaches for tagging by small vessels may cause behavioral changes in humpback whales, this change may be small and temporary. However, in female-calf groups, the behavioral change may be greater and longer lasting. This study shows that when using small vessels for behavioral research, disturbance, and recovery should be measured to ensure integrity of data used for other analyses.
... In the short-term, the behavior of some dolphin species changes when the number of boats around a school increases (Lusseau 2003, Constantine et al. 2004, Christiansen et al. 2010. The presence of tour boats may alter the path of travel (Williams and Ashe 2007) and even force the animals to dive to avoid the boats (Schaffar et al. 2013). Interactions with dolphin watching boats may also decrease time spent foraging (Christiansen et al. 2013). ...
... In British Columbia where salmon culturing is intensive and widespread, there is evidence that cetaceans are excluded from the inner reaches of bays where loud "seal scarers" are used to discourage pinnipeds from approaching salmon pens (Morton, 2000;Morton & Symonds, 2002;Olesiuk et al., 2002). Observations of avoidance responses by killer whales (Orcinus orca) to boats showed an apparent shift in avoidance behaviour at high traffic levels (Williams & Ashe, 2007). Habitat degradation is apparent in the traditional benthic feeding sites for the gray whale (Eschrichtius robustus) in the Bering Sea. ...
Marine cetaceans live within a vast aquatic environment that covers over 71% of the Earth’s surface.
Their habitats are foreign to humans, comprising extensive submerged landscapes of mountain ranges, plains, volcanoes and deep trenches; often eclipsing the size or majesty of many of their terrestrial counterparts. Driven by massive and layered currents and counter-currents, channels and columns of water, the ocean mass is a complex three dimensional environment. Within this complex environment are the migratory pathways and habitats of marine species - the living threads that weave throughout currents, channels, columns and basins; living conduits between separated ecosystems and habitats.
2. River cetaceans live in dynamic running water systems that emphasize terrestrial and upstream downstream connectivity. Their habitat is generally more familiar to humans compared with cetacean habitat in marine environments; together the Ganges and Yangtze River basins, in addition to supporting endangered cetaceans, sustain roughly 25 percent of the people living on Earth today. The habitat of these animals undergoes dramatic changes seasonally, expanding during high-water periods into small tributaries, appended lakes and sometimes flooded forests. The sensitivity of riverine environments to altered flow regimes caused by engineering structures and a changing climate pose particular challenges for protecting priority habitat, where the animals find refuge from downstream and tidal currents, and movement corridors along the main river course that connect these patchily distributed areas.
3. This review examines the progress and intent of CMS and its agreements to date and offers advice on
how the CMS Family can be more effective through strong collaboration with other relevant Multi-lateral
Environmental Agreements (MEAs) such as the International Maritime Organization (IMO), the International Whaling Commission (IWC) and its Scientific Committee (IWC SC) and Conservation Committee (IWC CC), the Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR), the United Nations Informal Consultation on Protection of the Oceans and the Law of the Sea (UNICPOLOS), the Cartagena Convention, European Union Habitats and Species Directive, the Bern Convention and the United Nations Environment Programme (UNEP) Regional Seas Programme.
... The level of horizontal avoidance by killer whales increased as the boat approached closer than 100 m, but as Williams et al. (2002b) noted, their response was not consistent as the number of boats increased. Experimental approaches by multiple vessels found that killer whales' path of travel becomes more linear once there are around three boats within 1000 m of the group and the avoidance tactic of shifting their path of travel as a way of avoiding a few boats is abandoned (Williams & Ashe, 2007). This research is important in our interpretation of killer whale behaviour where intense whale-watching activity occurs. ...
Within little more than a generation, whale-watching has been subject to global industrial development. It has been portrayed by destinations and business operators, and advocated by environmental groups, as a sustainable activity and an alternative to whaling. However, in recent years the sustainability of these activities has increasingly been questioned, as research shows that repeated disturbance by boat traffic can severely disrupt critical behaviours of cetaceans in the wild. Bringing together contributions by international experts, this volume addresses complex issues associated with commercial whale-watching, sustainable development and conservation of the global marine environment. It highlights widely expressed concerns for the failure of policy, planning and management and pinpoints both long-standing and emerging barriers to sustainable practice. Featuring numerous case studies, the book provides critical insights into the diverse socio-cultural, political, economic and ecological contexts of this global industry, highlighting the challenges and opportunities that arise along the pathways to sustainability.
... We analysed data from 6 years (1995-1998, 2002 and 2004), covering the months of July and August (Williams et al. 2002a(Williams et al. , b, 2006Williams and Ashe 2007). During the period, Chinook salmon catch per unit effort in the study area was six times higher in the highest year than in the lowest year (Lusseau et al. 2004). ...
Resident, fish-eating killer whales in the northeastern Pacific Ocean live in multi-generational matrilines containing both sexes. The degree of maternal fidelity and natal philopatry in this killer whale society is extreme even by the standards of lions, elephants or any highly social mammal. Benefits of group living include cooperative foraging and alloparental care, but few studies have explored how killer whales avoid within-group competition for prey. This study measured focal animal behaviour from one population in its legally designated critical habitat. Adult males and females overlapped spatially whilst resting, travelling and socialising, but during feeding bouts, females foraged nearshore in shallower waters, whilst adult males distributed foraging effort throughout the study area, with no statistically significant depth preference. We postulate that sex-biased dispersal in foraging ecology reflects physiological capacity for deeper diving in males than females, which may be either a driver or consequence of extreme sexual dimorphism in the species; alternative interpretations exist. Killer whales appear to be a cosmopolitan species complex including populations that range widely in body size and diet. Our physiological limitation theory could be tested with other ecotypes. For the northern resident killer whale population we studied, we postulate that our finding may indicate a mechanism to avoid or reduce competition for food within the family unit whilst ensuring group cohesion. Investigating sex differences in foraging habitat informs area-based management and conservation of this threatened population, but studies on other ecotypes are needed to improve our understanding of the evolution of sociality in this species.
... If animals react adopting opposite tactics to different level of disturbance (e.g. few or many boats), taking the average may mask the actual response, which could have happened in some of the considered studies (Williams & Ashe 2007). Thus, future research should look at boat number, proximity and vessel type. ...
ABSTRACT: Whale-watching activities can induce behavioral changes that may negatively affect cetacean populations. However, these changes may vary depending on species, populations and environmental features. It is important to determine inter-specific variation in cetacean responses to stressors in order to identify the best metrics for evaluation of consequences of anthropogenic disturbance. We used meta-analyses to assess the consistency of cetacean responses to whalewatching vessels across a pool of suitable studies covering a variety of species and sites. We analyzed several metrics to capture cetacean heterogeneous responses and to explore their reliability across species. We found disruptions of activity budget and of path directionality as the most consistent responses towards whale-watching vessels. In a similar manner across species, animals were more likely to travel and less likely to rest and forage in the presence of vessels. Cetaceans also showed a tendency to increase path sinuosity (deviation index) and decrease path linearity (directness index) during boat interactions. We also explored the influence of socio-ecological factors on behavioral response but found no consistent results among studies. Further population-specific studies should address the potential long-term consequences of these behavioral responses to inform management of the whale-watching industry.
... – for charismatic mega-fauna see Blane and Jaakson 1994; Au and Green 2000; Laist et al. 2001; Nowacek et al. 2001; Erbe 2002; Jelinski et al. 2002; Williams et al. 2002; Lusseau 2003a; 2003b; Constantine et al. 2004; Lemon et al. 2006; Williams and Ashe 2007; Stamation et al. 2010; Work et al. 2010; Lachmuth et al. 2011; Tseng et al. 2011; Wiley et al. 2011; and Steckenreuter et al. 2012; – for antifoulants see Talbot 1986; Nichols 1988; Becker-van Slooten and Tarradellas 1995; de Mora et al. 1995; Matthiessen et al. 1995; Dahl and Blanck 1996; Michel and Averty 1999; Voulvoulis et al. 1999; Axiak et al. 2000; Albanis et al. 2002; Haynes and Loong 2002; Schiff et al. 2004; Sayer et al. 2006; Sapozhnikova et al. 2007; Srinivasan and Swain 2007; Carson et al. 2009; Singh and Turner 2009b; 2009a; Turner 2010; and Yu et al. 2011; and – for oil spills see LaBelle and Anderson 1996; Eberhardt and Garrott 1997; Ketkar and Babu 1997; Batten et al. 1998; Dean et al. 1998; Feder and Blanchard 1998; Lancaster et al. 1998; Glegg et al. 1999; Hughes 1999; Seiser et al. 2000; Garshelis and Johnson 2001; Born et al. 2003; Janiot et al. 2003; Nikitik and Robinson 2003; Andersen et al. 2008; Piñeira et al. 2008; Melville et al. 2009; Dalton and Jin 2010; Song et al. 2011; and Vidal et al. 2011Althaus et al. (2007) outline a range of policy options that are available to governments to achieve their objectives (environmental or otherwise). These include advocacy (such as campaigns to encourage desired behaviour), money (such as taxes and grants), government action (such as the provision of public services), and law (such as legislation and regulations). ...
PhD Thesis 2011. Griffith School of Environment, Science, Environment, Engineering and Technology, Griffith University, Gold Coast, Queensland, Australia.
Abstract
There are approximately 1,500 tour boat operators with a combined fleet of approximately 3,800 vessels offering various sailing, fishing and diving activities in Australia’s marine environments. Many of these operate within marine protected areas (MPAs), such as the Great Barrier Reef Marine Park (GBRMP), and have the potential to adversely impact on human health and the environment from the operation of their vessels. These boating related environmental impacts stem from emissions and/or discharges of sewage, garbage, oil, greenhouse gases, antifouling agents and the physical disturbance of substrates, flora and fauna from anchoring, grounding, engine/propeller noise, vessel movement, etc.. There are, however, various measures available to promote more sustainable management of these boating related environmental impacts that involve regulation, voluntary programs and economic prompts. This thesis investigates the specific boating related environmental impacts of the industry on the marine environment and identifies opportunities to improve the environmental performance of Australian tour boat operators with respect to the operation of their vessels. Fieldwork was undertaken in Cairns, the Whitsundays, the Moreton Bay/Gold Coast region, Sydney, Melbourne, Broome and Exmouth. This thesis provides the first account of the standards and practices of the Australian tour boat industry making an original contribution to this field through the collection, presentation and interpretation of the new data. It also identified that the most effective ways to promote this is through the better education of operators to promote behavioural changes and practical measures on board. It is argued that a national tour boat operator organisation could assist in reducing environmental impacts and making the industry more sustainable.
... Several factors may influence population trends for resident killer whales. Among these, prey availability (Ford et al. 2005(Ford et al. , 2010aAyres et al. 2012), disturbance (Erbe 2002;Morton and Symonds 2002;Williams et al. 2002a,b;Williams and Ashe 2007;Lusseau et al. 2009) and pollution (Ross et al. 2000;Rayne et al. 2004;Ross 2006;Krahn et al. 2007b;Lachmuth et al. 2010Lachmuth et al. , 2011Williams et al. 2014) are of primary conservation concern (Fisheries and Oceans Canada 2011). Several other threats such as vessel strikes (Williams and O'Hara 2009), entanglement (Bigg and Wolman 1975;Fisheries and Oceans Canada 2011) and intentional shootings also have the potential to directly affect mortality rates of the northern and southern resident killer whale populations. ...
Field studies of the life history and ecology of killer whale populations off Canada’s west coast have been conducted annually since 1973. These studies are based on the identification of individual whales from photographs of permanent, natural markings. In this report, we summarize abundance trends in the northern resident killer whale population between 1974 and 2014, and provide an updated photo-identification catalogue of individuals. In 2014, the northern resident population was composed of 290 whales. The population has grown at an average mean annual rate of 2.2% since 1974. Continued population monitoring by photo-identification is a key research activity in the recovery strategy for this threatened population.
... In some cases these changes can have a direct and acute impact on an individual (e.g., a beaked whale responding to mid-frequency sonar, Tyack et al., 2011). Changes in acoustic environment can also have a more indirect and long-term influence on a population, such as prolonged and large-scale reduction in communication space for northern right whales ) and reduction in foraging efficiency in resident killer whales (Williams and Ashe, 2007). ...
This document describes an international research program called the International Quiet Ocean Experiment (IQOE). This experiment intends to document the global ocean soundscape over time, and well as developing new international cooperation on the effects of sound in the ocean on marine organisms.
... Activities of tourism vessels have been shown to negatively affect marine mammals. Noise generated by vessels may result in displacement or avoidance [13], increased stress, changes in swim-speed, foraging and diving behavior, and stranding of marine mammals (studies reviewed by [14]), and may also disrupt communication [15]. In a study of bottlenose dolphins (Tursiops spp.), the presence of vessels resulted in a decrease in resting, foraging, and socializing, and an increase in traveling [16]. ...
Large numbers of harbor seals (Phoca vitulina) use habitat in tidewater glaciers in Alaska for pupping, breeding, and molting. Glacial fjords are also popular tourist destinations; however, visitation by numerous vessels can result in disturbance of seals during critical life-history phases. We explored factors affecting haul-out behavior of harbor seals at a glacial site frequented by tourism vessels. In 2008-10, we deployed VHF transmitters on 107 seals in Endicott Arm, Alaska. We remotely monitored presence and haul-out behavior of tagged seals and documented vessel presence with time-lapse cameras. We evaluated the influence of environmental and physical factors on the probability of being hauled out, duration of haul-out bouts, and as factors associated with the start and end of a haulout. Location, season, hour, and interactions of location by year, season, hour, and sex significantly influenced haul-out probability, as did ice, weather, and vessels. Seals were more likely to be hauled out with greater ice availability during the middle of the day, and less likely to be hauled out if vessels were present. Cruise ships had the strongest negative effect; however, most vessel types negatively affected haul-out probability. Haul-out duration was longest in association with starting on incoming tides, clear skies, no precipitation, occurring in the middle of the day, and ending in the late afternoon or evening. End of haulouts was associated with increasing cloud cover, low ice availability, and vessel presence; large-sized tourism vessels or all-vessel-types combined were significant predictors of ending a haul-out bout. Probability of being hauled out was highest in June, during pupping season. Potential disturbances of harbor seals could be reduced, enabling longer resting times for seals and fewer interruptions for nursing pups, if vessels focused the majority of visits to glacial habitat to before or after the hours of 08:00-17:00 or, less optimally, 09:00-16:00.
... At sea, positions have been estimated by using the vertical angle between an object and the horizon (Gordon 2001), from overhead video cameras mounted on tethered airships (Nowacek et al. 2001), and by combining laser range finders with compass bearings measured with a GPS (Curé et al. 2012). Some approaches to monitoring marine animals from land can use theodolites, which measure the horizontal and vertical angles to a target (Bejder et al. 2006;Williams and Ashe 2007), but these instruments require a stable platform, and they generally only sample one individual at a time. Thus, new equipment would be helpful for studying fast-moving groups of animals in the field over longer time periods and distances. ...
Here, we describe a portable stereo camera system that integrates a GPS receiver, an attitude sensor and 3D stereo photogrammetry to rapidly estimate the position of multiple animals in space and time. We demonstrate the performance of the system during a field test by simultaneously tracking the individual positions of six long-finned pilot whales, Globicephala melas. In shore-based accuracy trials, a system with a 50-cm stereo baseline had an average range estimation error of 0.09 m at a 5-m distance increasing up to 3.2 at 50 m. The system is especially useful in field situations where it is necessary to follow groups of animals travelling over relatively long distances and time periods whilst obtaining individual positions with high spatial and temporal resolution (up to 8 Hz). These positions provide quantitative estimates of a variety of key parameters and indicators for behavioural studies such as inter-animal distances, group dispersion, speed and heading. This system can additionally be integrated with other techniques such as archival tags, photo-identification methods or acoustic playback experiments to facilitate fieldwork investigating topics ranging from natural social behaviour to how animals respond to anthropogenic disturbance. By grounding observations in quantitative metrics, the system can characterize fine-scale behaviour or detect changes as a result of disturbance that might otherwise be difficult to observe.
... However, these responses are not ubiquitous across species, nor are they consistent within a species across all contexts (e.g., responses when feeding may differ from when resting, breeding or migrating). Furthermore, whether a behavioural response is observed often depends on the number of vessels present (e.g., Constantine et al., 2004;Williams and Ashe, 2007;Williams et al., 2009), the type of vessel (e.g., Goodwin and Cotton, 2004), and the manner in which and how closely vessels approach the animal(s) being observed (e.g., Hodgson and Marsh, 2007;Lemon et al., 2006;Lundquist et al., 2013;Williams et al., 2009Williams et al., , 2002a. It is typically concern about these short-term responses, along with precautionary principles, that have given rise to the various regulations and guidelines implemented by government agencies and used by the commercial whale-watching industry. ...
In recent years there has been significant interest in modelling cumulative effects and the population consequences of individual changes in cetacean behaviour and physiology due to disturbance. One potential source of disturbance that has garnered particular interest is whale-watching. Though perceived as ‘green’ or eco-friendly tourism, there is evidence that whale-watching can result in statistically significant and biologically meaningful changes in cetacean behaviour, raising the question whether whale-watching is in fact a long term sustainable activity. However, an assessment of the impacts of whale-watching on cetaceans requires an understanding of the potential behavioural and physiological effects, data to effectively address the question and suitable modelling techniques. Here, we review the current state of knowledge on the viability of long-term whale-watching, as well as logistical limitations and potential opportunities. We conclude that an integrated, coordinated approach will be needed to further understanding of the possible effects of whale-watching on cetaceans.
... If animals react adopting opposite tactics to different level of disturbance (e.g. few or many boats), taking the average may mask the actual response, which could have happened in some of the considered studies (Williams & Ashe 2007). Thus, future research should look at boat number, proximity and vessel type. ...
... For instance, the effects of recreation and tourism on wildlife have become a concern in many protected areas. Thus, researchers are now perform-ing studies to quantify these effects, such as observing the minimum distance from humans tolerated by large ungulates (Malo, Acebes, and Traba 2011;Stankowich 2008), or the maximum number of boats tolerated by marine animals (Williams and Ashe 2007). These studies are highly informative in the creation of park regulations that protect animals from behavioral disturbances, while allowing visitors to observe the animals they have come to see. ...
... Bauer et al. 1993), killer whales Orcinus orca (e.g. Bain et al. 2006, Williams & Ashe 2007, bottlenose dolphins Tursiops spp. (e.g. ...
The largest southern hemisphere humpback whale Megaptera novaeangliae stock
(E1) uses the east coast of Australia as a migratory corridor to travel between their high-latitude
feeding grounds in the Southern Ocean and low-latitude breeding grounds in northeast Queensland
and the south-west Pacific Ocean. The population is recovering at close to the maximum rate
of growth (rm), and the increasing abundance of whales passing within sight of land has facilitated
the development of a growing land- and vessel-based whale watching industry. We observed the
behaviour of 156 individual pods of humpback whales passing Sydney, New South Wales, during
their 2006 and 2007 northern migration and monitored vessel−whale interactions with respect to
the Australian National Guidelines for Whale and Dolphin Watching 2005. We applied generalised
linear mixed models with random effects to compute the odds of changing to the current
behaviour state. We found that in the presence of vessels, whales were more likely to remain on
the surface breathing or to cease surface breathing and switch to generally short, shallow diving
than was the case when no vessels were present. Northerly migrating whales off Sydney were
more likely to remain on the surface breathing in the presence of vessels, rather than taking some
form of vertical avoidance (deep, long dives) as reported elsewhere. Given the high rate of population
increase of stock E1 and the low level of behavioural changes seen, it appears that for this
population at least, adult humpback whales migrating to their breeding grounds are relatively
robust to disturbance by whale watching.
... In the short-term, the behavior of some dolphin species changes when the number of boats around a school increases (Lusseau 2003, Constantine et al. 2004, Christiansen et al. 2010. The presence of tour boats may alter the path of travel (Williams and Ashe 2007) and even force the animals to dive to avoid the boats (Schaffar et al. 2013). Interactions with dolphin watching boats may also decrease time spent foraging (Christiansen et al. 2013). ...
[Extract] A global review of tourist visitation and expenditures associated with whale and dolphin watching industries indicated that the industry attracted 13 million tourists in 119 countries and contributed US$ 2.1 billion to the global economy in 2008 (O'Connor et al. 2009). O'Connor et al. (2009) indicated that nine of the 10 countries with the fastest rate of whale and dolphin watching industries were developing countries.
Whale and dolphin watching is not without risks to targeted populations. In the short-term, the behavior of some dolphin species changes when the number of boats around a school increases (Lusseau 2003, Constantine et al. 2004, Christiansen et al. 2010). The presence of tour boats may alter the path of travel (Williams and Ashe 2007) and even force the animals to dive to avoid the boats (Schaffar et al. 2013). Interactions with dolphin watching boats may also decrease time spent foraging (Christiansen et al. 2013). In addition, dolphin watching may eventually partially displace the target population from key habitats, as demonstrated during a 19 yr research study in Shark Bay, Western Australia (Bejder et al. 2006).
... The short median passage duration relative to the size of the study sites indicates that the acoustically-detected passages corresponded to the time when a boat was close to the hydrophones. Reinforcing the role of boat physical presence, the visual data showed that the effect increased for increasing numbers of boats in the area (Williams and Ashe, 2007;Pirotta et al., 2013). Dolphins appeared to temporarily interrupt their activity when disturbed, staying in the area and quickly resuming foraging as the boat moved away. ...
... Motorised vessels appear to have a high disturbance potential for marine animals (e.g. Lesage et al., 1999;Nowacek et al., 2001;Erbe, 2002;Williams et al., 2002;Lemon et al., 2006;Williams & Ashe, 2006), although some species do exhibit varying degrees of tolerance (see Gregory & Rowden, 2001;Sini et al., 2005). While direct effects of vessels may be easily identified, indirect impacts are clearly more difficult to quantify. ...
... Given the recent introduction of dolphin tourism in GSV and the apparent susceptibility of foraging common dolphins to tour boat interactions in New Zealand (reduced foraging bouts when tour vessels are present) (Stockin et al. 2008), it is important to understand the importance of GSV waters for foraging common dolphins. This is of notable importance given that, worldwide, a variety of short-term changes in behaviour in response to tourism activity has been detected for numerous cetacean species (Lemon et al. 2006;Stamation et al. 2007;Williams and Ashe 2007;Carrera et al. 2008;Dans et al. 2008;Duprey et al. 2008;Stockin et al. 2008;Arcangeli et al. 2009;Lusseau et al. 2009). Long-term studies indicate that these short-term behavioural changes can lead to detrimental long-term consequences (e.g. ...
Common dolphins are subject to large-scale fishing activity and tourism operations in South Australia; however, there is a paucity of data on this species. Understanding the behaviour of a population can contribute greatly to our knowledge of a species and how to manage potential population-level threats. This paper describes the behaviour of short-beaked common dolphins (Delphinus delphis) in Australian waters for the first time. Data were collected from 109 independent dolphin groups during boat-based surveys conducted in Gulf St Vincent, South Australia, between September 2005 and May 2008. Activity budgets were used to assess behaviour of common dolphins in relation to diel patterns, season, water depth, sea surface temperature (SST), group size and composition. Foraging (33.9%) and resting (2.8%) were the most and least frequently observed behaviours, respectively. Travelling (33.0%), socialising (20.2%) and milling (10.1%) accounted for the remainder of the activity budget. Diurnal differences were detected, with foraging (59.5%) and socialising (31.8%) groups most frequently observed from 10.00 to 11.59 hours. Behaviour did not vary seasonally or with water depth, SST, group size or composition. Behaviour varied significantly between single-and multispecies aggregations. Foraging was more frequent in multispecies aggregations, as 78.4% of all foraging behaviour observed for common dolphins occurred in the presence of other species. Multispecies aggregations were most frequently observed with flesh-footed shearwaters (Puffinus carneipes), which were present during 29.4% of common dolphin encounters. Behaviour varied significantly during aggregations with shearwaters, as 62.2% of foraging groups occurred in the presence of shearwaters. Resting, milling or socialising was rarely observed in the presence of any other species, indicating that the primary mechanism for aggregations is likely prey-related.
In 1994, the United States government removed the Eastern North Pacific gray whale from the Endangered Species List due to its recovery rather than extinction. This notable action also marked the first removal of a marine mammal from the List due to population recovery since its enactment in 1973. The gray whale case study is well documented, in large part due to the charismatic nature of whales, a deep regard for marine mammal species, multiple federal laws and international treaties involved in their management and recovery, and a series of legal cases involving the Makah tribe in its pursuit to resume cultural subsistence whaling. The events leading up to the gray whale’s listing as endangered, the actions taken by both the US and the international community, and some of the events since the species’ delisting creates a unique and comprehensive case study that provides space for reflection on the future use of environmental laws to protect and preserve species, including, but certainly not limited to, large cetaceans in the Anthropocene.
Most of the species from the order Cetacea appear to possess advanced cognitive abilities and close social networks and are also likely to experience different affective states comprising of more than just basic emotions. Welfare describes a balance of positive and negative affective states experienced by an individual, and this balance is a good indicator of how it perceives the surrounding environment. In this chapter, we discuss how the first steps in cetacean welfare science are being taken to establish this as a discipline. We discuss the pertinent areas of cetology that merit investigation to form the basis of possible cetacean welfare measures. In this arena of welfare assessment, much of the existing work comes from farm animal science, and this previous experience offers potential tools and techniques which could be adapted for cetaceans. We review these sources of information, make suggestions for relevant investigations and discuss how assessment of cetacean welfare might be accomplished.
Many studies have demonstrated short-term behavioural responses by whales and dolphins in the presence of vessels, but the population-level implications of such changes are poorly understood (Lusseau, 2003, 2004; Bejder et al., 2006a; Lusseau & Bejder, 2007). One means for developing such an understanding is to use a modelling framework such as the Population Consequences of Acoustic Disturbance (PCAD) model. PCAD identifies four levels at which data can be collected, and allows for estimates of modelling parameters at one level to be based on measured data at another level (National Research Council, 2005). The first level contains short-term behavioural responses, such as those that have been the typical focus of studies on effects of whale-watching. Effects vary within and between species, and include changes in respiration patterns, surface active behaviours, swimming velocity, vocal behaviour, activity state, inter-individual spacing, wake riding, approach and avoidance, and displacement from habitat. Collisions may result in injury or death (Wells & Scott, 1997; Laist et al., 2001). More detailed reviews of vessel effects can be found in Lien (2001) and Ritter (2003).
Scientists conducting research on cetaceans have a variety of publication outlets. However, a formal assessment of those options has not been conducted. To better understand the trends in publications regarding dolphins and whales, we surveyed peer-reviewed articles from 9 different databases. Our survey produced 1,628 unique articles involving 16 cetaceans found both in the wild and in captivity. Each article was coded a variety of information: habitat, geographic location, genus, topic, research design, and journal type. The analyses indicated that 68% studies were conducted with wild populations and 29% were performed with captive populations. A quarter of the journals publishing research on dolphins or whales published almost 80% of all the articles selected for this study. Studies were conducted across many different geographic locations and topics. Other major findings elucidated relationships between various variables. As expected, specific topics were more likely associated with certain research designs, habitats, and journal types. One of the most important findings of this study is the limited publication of research conducted with captive cetaceans. While it is important to continue to examine animals in their natural environments, there is much to be learned from studies conducted with animals in captivity. As a group, we must become cognizant of the publication trends which currently describe our research progress as we integrate our knowledge from captivity and the wild.
Although a healthy environment is generally recognized as an important public good, environmental regulation often meets significant opposition. The legitimacy of environmental law is thus very much an uncertain political project, as is evident in many struggles over environmental protection. I use and extend literatures on legal consciousness, legal geographies, and environmental regulation to analyze a controversy that emerged over efforts to regulate vessels in the presence of endangered orca whales in the Pacific Northwest. I suggest that a significant component of the opposition to these regulations stemmed from a widespread distrust and fear of the federal government. This distrust and fear were sharply accentuated by the fact that the regulations were to be imposed on the space of the sea, an area commonly viewed as best left unregulated or as deeply unregulatable. Given the arguable need for robust state action to protect the environment, on the sea as well as on land, these ambient fears are significant, and pose notable obstacles to the legitimacy of environmental law.
Mammalian predator-prey systems are behaviorally sophisticated games of stealth and fear. But, traditional mass-action models of predator prey dynamics treat individuals as behaviorally unresponsive "molecules" in Brownian motion. Foraging theory should provide the conceptual framework to envision the interaction. But, current models of predator feeding behavior generally envision a clever predator consuming large numbers of sessile and behaviorally inert prey (e.g., kangaroo rats, Dipodomys, collecting seeds from food patches). Here, we extend foraging theory to consider a predator-prey game of stealth and fear and then embed this game into the modeling of predator-prey population dynamics. The melding of the prey and predator's optimal behaviors with their population and community-level consequences constitutes the ecology of fear. The ecology of fear identifies the endpoints of a continuum of N-driven (population size) versus mu-driven (fear) systems. In N-driven systems, the major direct dynamical feedback involves predators killing prey, whereas mu-driven systems involve the indirect effects from changes in fear levels and prey catchability. In mu-driven systems, prey respond to predators by becoming more vigilant or by moving away from suspected predators. In this way, a predator (e.g., mountain lion, Puma concolor) depletes a food patch (e.g., local herd of mule deer, Odocoileus hemionus) by frightening prey rather than by actually killing prey. Behavior buffers the system: a reduction in predator numbers should rapidly engender less vigilant and more catchable prey. The ecology of fear explains why big fierce carnivores should be and can be rare. In carnivore systems, ignore the behavioral game at one's peril.
Complex, human-dominated landscapes provide unique challenges to animals. In landscapes fragmented by human activity, species whose home ranges ordinarily consist of continuous habitat in pristine environments may be forced to forage among multiple smaller habitat patches embedded in an inhospitable environment. Furthermore, foragers often must decide whether to traverse a heterogeneous suite of landscape elements that differ in risk of predation or energetic costs. We modeled population consequences of foraging decisions for animals occupying patches embedded in a heterogeneous landscape. In our simulations, animals were allowed to use three different rules for moving between patches: a) optimal selection resulting from always choosing the least-cost path; b) random selection of a movement path; and c) probabilistic selection in which path choice was proportional to an animal's probability of survival while traversing the path. The resulting distribution of the population throughout the landscape was dependent on the movement rule used. Least-cost movement rules (a) produced landscapes that contained the highest average density of consumers per patch. However, optimal movement resulted in an all-or-none pattern of occupancy and a coupling of occupied patches into pairs that effectively reduced the population to a set of sub-populations. Random and probabilistic rules, (b and c), in relatively safe landscapes produced similar average densities and 100% occupancy of patches. However, as the level of risk associated with travel between patches increased, random movement resulted in an all-or-none occupancy pattern while occupied patches in probabilistic populations went extinct independently of the other patches. Our results demonstrate strong effects of inter-patch heterogeneity and movement decisions on population dynamics, and suggest that models investigating the persistence of species in complex landscapes should take into account the effects of the intervening landscape on behavioral decisions affecting animal movements between patches.
I assessed the short-term reactions of bottlenose dolphins Tursiops spp. to interactions with tour boats, and their long-term implications. Vertical avoidance of boats, showed by an increase in time spent underwater, is a typical response in cetaceans, and has been likened to predator avoidance strategies. This study looked at the variation in diving pattern of bottlenose dolphins in Doubtful Sound, New Zealand, in relation to boat interactions. An observing vessel was used to collect the data. A regressive approach showed that this vessel did not have a significant effect on the diving pattern of the dolphins. The analysis would have allowed the detection of a small difference (6.35 s) in dive interval (percentage of variance, PV = 0.05) with high certainty (power = 0.86). Dolphins avoided tour boats vertically by increasing their mean diving interval. Dolphins started to react before boats were in visual contact. An information theoretic approach indicated that the behaviour of the boat was the predominant factor affecting the diving interval. Males and females responded differently to interactions with boats. Males started to avoid boats as soon as they were present, while females switched to a vertical avoidance strategy only when interactions became intrusive. This difference in avoidance strategy may be related to the different metabolic regime of the sexes. Males would be more likely to meet the cost of vertical avoidance of boats because of their greater energy stores. Females vertically avoid boats, an energetically expensive exercise for them, only when the risk incurred by this interaction is high.
Marine tourism has surfaced as a pressing topic in the field of ocean and coastal management. Neither necessarily good, nor bad, this tourism is inherently controversial. Today, demand for travel exhibits greater variation and magnitude than ever in history. In response, the tourism industry has become the largest business on earth. This, coupled with the respect people profess for marine environments and local peoples, creates feelings of ambivalence for the tourist. Sociologically, the activity of tourism may be studied as a symbolic interaction fostering social solidarity. Ecotourism, a recent phenomenon attuned to the ideal of sustainable development, is suggested to emerge through the social construction processes of restoration and enhancement. The papers in this theme volume add fuel to the proposition that the resolution of tourism problems in the coastal zone will require the scientific study of environmental and social conditions, policy analyses, planning, and public education.
A population of bottlenose dolphins inhabits 7 of the 14 fjords that compose Fiordland, New Zealand. One of these fjords, Milford Sound, supports a large tourism industry that results in intense boat traffic. Bottlenose dolphins regularly visited Milford Sound and tour boats interacted with them during these visits. I studied the factors affecting the frequency of visits to Milford Sound by relating the residency pattern of dolphins in this fjord to oceanographic parameters and variations in boat traffic between December 1999 and February 2002. Boat traffic was the only variable that could explain the frequency of dolphin visits to Milford Sound. Dolphins spent less time in Milford Sound during seasons of intense boat traffic. Moreover, when dolphins visited this fjord, they spent more time at the entrance of the fjord when boat traffic was intense, out of the reach of tour boats. It seems that dolphins avoid Milford Sound when traffic is heavy. This avoidance could have long-term implications for the demography of the population.
Predation is often implicated as the most important factor determining differential microhabitat use by small mammals, particularly in desert ecosystems. This generalization, however, is based primarily on observational and correlational approaches and only a few field experimental studies. In a large scale, long-term experimental manipulation of predators in semiarid north-central Chile, we studied the effects of excluding vertebrate predators on the space use of a small mammal species. We used three different techniques to determine space use under and away from shrubs by the diurnal, herbivorous rodent Octodon degus. These included smoked tiles, fluorescent pigment tracking, and tabulation of numbers of runways among shrubs. Results show that O. degus used spaces away from shrubs more often, made more (and less straight) runways between shrubs and had smaller daily home ranges in grids where predators were excluded. Thus, besides the well known predator effects of density depression and survival reduction of their prey, our study demonstrates experimentally that prey respond behaviorally to perceived predation risks.
Mammalian predator-prey systems are behaviorally sophisticated games of stealth and fear. But, traditional mass-action models of predator prey dynamics treat individuals as behaviorally unresponsive "molecules" in Brownian motion. Foraging theory should provide the conceptual framework to envision the interaction. But, current models of predator feeding behavior generally envision a clever predator consuming large numbers of sessile and behaviorally inert prey (e.g., kangaroo rats, Dipodomys, collecting seeds from food patches). Here, we extend foraging theory to consider a predator-prey game of stealth and fear and then embed this game into the modeling of predator-prey population dynamics. The melding of the prey and predator's optimal behaviors with their population and community-level consequences constitutes the ecology of fear. The ecology of fear identifies the endpoints of a continuum of N-driven (population size) versus μ-driven (fear) systems. In N-driven systems, the major direct dynamical feedback involves predators killing prey, whereas μ-driven systems involve the indirect effects from changes in fear levels and prey catchability. In μ-driven systems, prey respond to predators by becoming more vigilant or by moving away from suspected predators. In this way, a predator (e.g., mountain lion, Puma concolor) depletes a food patch (e.g., local herd of mule deer, Odocoileus hemionus) by frightening prey rather than by actually killing prey. Behavior buffers the system: a reduction in predator numbers should rapidly engender less vigilant and more catchable prey. The ecology of fear explains why big fierce carnivores should be and can be rare. In carnivore systems, ignore the behavioral game at one's peril.
The research and whalewatching communities of Johnstone Strait, British Columbia, Canada have worked closely together to identify whalewatching practices that minimise disturbance to northern resident killer whales. Local guidelines request that boaters approach whales no closer than 100m. Additionally, boaters are requested not to speed up when close to whales in order to place their boat in a whale's predicted path: a practice known as 'leapfrogging'. A land-based study was designed to test for behavioural responses of killer whales to an experimental vessel that leapfrogged a whale's predicted path at distances greater than 100m. Ten male killer whales were repeatedly approached and the animals responded on average by adopting paths that were significantly less smooth and less straight than during preceding, control conditions. This adoption of a less 'predictable' path is consistent with animals attempting to evade the approaching boat, which may have negative energetic consequences for killer whales. The results support local consensus that leapfrogging is a disruptive style of whalewatching, and should be discouraged. Similarly, as the experimental boat increased speed to overtake the whale's path, the source level of engine noise increased by 14dB. Assuming a standard spherical transmission loss model, the fast-moving boat would need to be 500m from the whale for the received sound level to be the same as that received from a slow-moving boat at 100m. Whalewatching guidelines should therefore encourage boaters to slow down around whales, and not to resume full speed while whales are within 500m.
The authors observed disturbances to harbor seals and the seals' responses to the disturbances during 1991 and 1992 at Puffin Island, Clements Reef, and Skipjack Island, Washington. Harassment of seals on shore was common and caused mainly by operators of powerboats coming close to observe the seals. The number of seals that returned to preharassment levels after a disturbance was less at Puffin Island than at the other two sites. Seals were also more vigilant at Puffin Island. This greater intolerance of disturbance at Puffin Island could be due to the larger numbers of pups on shore there than at the other sites. The authors experimented to see if the seals on Puffin Island would be disturbed by powerboats at greater distances. A theodolite was used at Puffin Island and Clements Reef to determine distances between seals and approaching boats. No significant differences in distances of disturbance were found. Differences were noted in distance of disturbance between initial and subsequent disturbances during a haul-out period. lgh.
Machalilla National Park, on the coast of mainland Ecuador, supports a growing whalewatching industry that focuses on Southern Hemisphere humpback whales, which spend the austral winter (June-September) in this area. This study was designed to measure short-term reactions of whales to the whalewatching vessel activity typically seen in this area for two reasons: (1) to identify the nature of whales' avoidance response, if any, in order to draft whalewatching guidelines that help local mariners identify when they may be disturbing whales; and (2) to quantify the magnitude of any avoidance response, to examine how this relatively understudied population behaves around boats compared with whales in other whalewatching areas. A shore-based theodolite tracking team created a 'natural' experiment to observe relationships between whalewatching traffic and whale behaviour in 1998 and 1999. Swim speed and path directness of humpback whales were measured in the absence of boats, and how those parameters changed when boats arrived was recorded. When whales entered the study area accompanied by boats, a record was made of how their behaviour changed after the boats left. Humpback whales reacted to the approach of whalewatching boats by increasing swim speed significantly, and adopted a much more direct path after boats left. Future research is needed to determine whether responses vary with number, proximity or type of vessel. Similarly, future studies are recommended to determine whether different age-sex classes vary in vulnerability to disturbance. Meanwhile, this study enables provision of much-needed, practical advice to local operators who are concerned that they may be disturbing whales: one way that mariners can tell if they are causing disturbance is if they need to increase their vessel's speed to keep pace. The average behavioural responses measured were strong enough to recommend that Machalilla National Park adopt precautionary management procedures to limit number and proximity of vessels.
Marine ecotourism in New Zealand presents a challenging tourism-environment management context. This is demonstrated in the case of Doubtful Sound (New Zealand) where the recent proliferation of tour operators has brought pressures to bear upon a population of bottlenose dolphins resident in the sound. Strict methodologies are necessary to objectively interpret responses to tourism-induced anthropogenic impacts upon cetaceans. Previous research in this field has established that boat interactions with dolphins in Doubtful Sound affect the behavioural budget of the dolphin population, and that dolphins are more sensitive to interactions with boats when they are resting and to a lesser extent when they are socialising. This article reports on a programme of research that employed observational data to explore the applicability of tourism management techniques grounded in spatial ecology. The data provided scientific evidence that determining critical habitat through spatio-ecological analysis is a powerful tool to protect marine mammals in New Zealand, and elsewhere, from biologically significant tourism-induced impacts. The delineation of multi-levelled marine sanctuaries may, therefore, be an effective approach to managing the impacts of tourism upon marine mammals.
We investigated how large carnivores, herbivores, and plants may be linked to the maintenance of native species biodiversity
through trophic cascades. The extirpation of wolves (Canis lupus) from Yellowstone National Park in the mid-1920s and their reintroduction in 1995 provided the opportunity to examine the
cascading effects of carnivore–herbivore interactions on woody browse species, as well as ecological responses involving riparian
functions, beaver (Castor canadensis) populations, and general food webs. Our results indicate that predation risk may have profound effects on the structure
of ecosystems and is an important constituent of native biodiversity. Our conclusions are based on theory involving trophic
cascades, predation risk, and optimal foraging; on the research literature; and on our own recent studies in Yellowstone National
Park. Additional research is needed to understand how the lethal effects of predation interact with its nonlethal effects
to structure ecosystems.
"Few studies have examined the effects of human development on fine-scale movement behavior, yet understanding animal movement through increasingly human-dominated landscapes is essential for the persistence of many wild populations, especially wary species. In mountainous areas, roads and trails may be particularly deserving of study because they are concentrated in the valley bottoms where they can impede animal movement both across and between valleys. In this study, we tracked wolf (Canis lupus) movement in the snow for two winters in Jasper National Park, Alberta, Canada to examine how wolves navigate through or around human-use features. We quantified the effects of human development and topography on the tortuosity of wolf paths and then tested the permeability of roads, trails, and a railway line to wolf movement by comparing the frequency with which actual wolf paths and a null model of random paths crossed these features. Wolf path tortuosity increased near high-use trails, within areas of high-trail and road density, near predation sites, and in rugged terrain. Wolves crossed all roads, trails, and the railway line 9.7% less often than expected, but avoided crossing high-use roads more than low-use trails. Surprisingly, trails affected movement behavior of wolves equally, if not more, than roads. These results suggest that although roads and trails in this study were not absolute barriers to wolf movement, they altered wolf movements across their territories."
"A growing number of studies quantify the impact of nonlethal human disturbance on the behavior and reproductive success of animals. Athough many are well designed and analytically sophisticated, most lack a theoretical framework for making predictions and for understanding why particular responses occur. Behavioral ecologists have recently begun to fill this theoretical vacuum by applying economic models of antipredator behavior to disturbance studies. In this emerging paradigm, predation and nonlethal disturbance stimuli create similar trade-offs between avoiding perceived risk and other fitness-enhancing activities, such as feeding, parental care, or mating. A vast literature supports the hypothesis that antipredator behavior has a cost to other activities, and that this trade-off is optimized when investment in antipredator behavior tracks short-term changes in predation risk. Prey have evolved antipredator responses to generalized threatening stimuli, such as loud noises and rapidly approaching objects. Thus, when encountering disturbance stimuli ranging from the dramatic, lowflying helicopter to the quiet wildlife photographer, animal responses are likely to follow the same economic principles used by prey encountering predators. Some authors have argued that, similar to predation risk, disturbance stimuli can indirectly affect fitness and population dynamics via the energetic and lost opportunity costs of risk avoidance. We elaborate on this argument by discussing why, from an evolutionary perspective, disturbance stimuli should be analogous to predation risk. We then consider disturbance effects on the behavior of individuals--vigilance, fleeing, habitat selection, mating displays, and parental investment--as well as indirect effects on populations and communities. A wider application of predation risk theory to disturbance studies should increase the generality of predictions and make mitigation more effective without over-regulating human activities."
"Increasingly, whales and dolphins are the focus of tourism activities in many coastal locations. Although these activities can affect individuals and populations of cetaceans, the biological significance and hence the cost of these impacts are as yet largely unknown. This study assessed the effects of boat interactions on the behavioral budget of two populations of bottlenose dolphins (Tersiops truncatus) living in similar fjords but exposed to different levels of tourism activities. This comparison makes it possible to assess the costs of short-term avoidance strategies and the threshold at which those strategies are no longer effective. The effects of boat interactions were the same in both fjords. The resting state was the most sensitive to interactions; socializing was less sensitive. Short-term displacement was a typical response to boat exposure: dolphins were more likely to travel after an interaction with a vessel. Although the behavioral budgets of these populations were significantly altered during interactions with boats, their overall behavioral budgets were unchanged. Dolphins in Milford Sound actively avoided boat interactions, possibly to maintain their overall behavioral budget unchanged. This active avoidance led to avoidance of the area. Characteristics of dolphin-boat interactions in Milford Sound suggest that the advantages gained by short-term avoidance are lost if, on average, fewer than 68 min elapse between successive interactions with boats. If dolphin-boat interactions were more frequent than this, the dolphins switched to a longer-term response: area avoidance."
Most studies of the effects of human disturbance on grizzly bears (Ursus arctos horribilis) have not quantified the energetic effects of such interactions. In this study, we characterized activity budgets of adult grizzly bears as they foraged on aggregations of adult army cutworm moths (Euxoa auxiliaris) in the alpine of Glacier National Park, Montana, during 1992, 1994, and 1995. We compared the activity budgets of climber-disturbed bears to those of undisturbed bears to estimate the energetic impact of climber disturbance. When bears detected climbers, they subsequently spent 53% less time foraging on moths, 52% more time moving within the foraging area, and 23% more time behaving aggressively, compared to when they were not disturbed. We estimated that grizzly bears could consume approximately 40,000 moths/day or 1,700 moths/hour. At 0.44 kcal/moth, disruption of moth feeding cost bears approximately 12 kcal/minute in addition to the energy expended in evasive maneuvers and defensive behaviors. To reduce both climber interruption of bear foraging and the potential for aggressive bear-human encounters, we recommend routing climbers around moth sites used by bears or limiting access to these sites during bear-use periods.
Using predaceous diving beetle larvae (Dytiscus verticalis) and 2 species of anuran tadpole prey (Rana sylvatica, Hyla versicolor), examined the hypothesis that when both predator and prey are relatively mobile and there is no spatial refuge for the prey, the combined behavioral responses of the predator and prey will result in no clear pattern of relative spatial distribution. The predator and both species of prey exhibited a distinct preference for the most complex microhabitat when each was alone. When predator and prey were together, a shift occurred in their microhabitat preference such that they were uniformly distributed throughout the available microhabitats. -from Authors
As a suhsidiary result of a study on social behaviour of Thomson's gazelle in Serengeti National Park (Tanzania) there are given informations on flight behaviour and avoidance of predators. Alert posture, flight in galloping and stotting, and especially the relatively soft alarm call are more or less contagious and can release alertness or flight in conspecifics. Shaking of the flank (BROOKS, 1961) does not initiate flight only but galloping in general. It is the last link in a chain of actions which appears completed only in intraspecific situations. In perception of enemies the tommy reacts to optical stimuli from silhouettes and movements. The senses of smell and hearing are not so important in this context. If the tommies have recognized an enemy in time they try to keep it under control (behaviour of fascination). The territorial ♂♂ are especially important in this context. Bachelor herds are found predominantly at the periphery of an area inhabited by a gazelle population. Thus predators often encounter them first. Gaits and behaviour patterns in flight are described with special regard to stotting display. The young fawns stay put (Abliegen, WALTHER, 1059/60) and so are difficult to be seen. The way in which the mother manages her fawn especially during the first days of its life lead to the view that the fawn and the place where it rests are kept from contamination with odors attractive to predators. In rare cases even adult gazelles try to evade predators by lying down. Tommies do not fight against predators when hunted. The mother defends her fawn against jackals and tries to divert hyenas which hunt for her fawn. Factors which influence the flight distance are discussed. The flight distance varies with the different predators according to their danger for gazelles. Experiments showed that adult ♂♂ in herds (bachelors) have a lesser flight distance than ♀♀ in herds, adult ♂♂ have a lower one than subadult ♂ ♂, territorial ♂♂ have a lower one than adult bachelors, but solitary wandering ♂♂ show the greatest flight distance of all gazelles. Thus age, sex and social status are all significant factors influencing flight distance. By observations of the behaviour in response to predators, human beings, cars and especially by the study of the mistakes in flights from animals which are not predators of gazelles, it was possible to find a few flight releasing factors, most of them similar to or identical with sign stimuli: sudden appearance, direct course (toward the gazelles), size, good perceptibility (contrast), large number of enemies, high speed, proximity, strangeness, and experience. In concrete cases usually several of these factors operate concomitantly. A remarkable number of them are also known as factors which release the following reaction in young ungulates (WALTHER, 1964a, 1966). This may explain certain cases of ambivalent behaviour, especially of gazelle fawns in regard to predators. A few observations on kills of predators lead me to the view that the age, sex and social groups are preyed upon by various predators at different rates. There are relationships between the differences in flight distances, and the spatial distribution according to the social grouping of gazelles on the one hand, and the different hunting methods of the predators on the other hand. The ecological importance of each predatory species depends on its specialization and preference for gazelles as prey animals, its number, and its preferred biotype. Implications for the management of national parks and game cropping outside the protected areas are discussed. Thomson's gazelles show very few behaviour patterns of alertness, alarm, flight and hiding that are restricted to predators only; most patterns are also seen in intraspecific situations. Certain observations lead to the view that these behaviour patterns are adapted primarily to special conditions of the intraspecific realm and work better in it.
Whale displacement by acoustic "pollution" has been difficult to document, even in cases where it is strongly suspected, because noise effects can rarely be separated from other stimuli. Two independent studies on the natural history of killer whales (Orcinus orca) monitored frequency of whale occurrence from January 1985 through December 2000 in two adjacent areas: Johnstone Strait and the Broughton Archipelago. Four high-amplitude, acoustic harassment devices (AHDs) were installed throughout 1993 on already existing salmon farms in the Broughton Archipelago, in attempts to deter predation on fish pens by harbour seals (Phoca vitulina Linnaeus). While whale occurrence was relatively stable in both areas until 1993, it then increased slightly in the Johnstone Strait area and declined significantly in the Broughton Archipelago while AHDs were in use. Both mammal-eating and fish-eating killer whales were similarly impacted. Acoustic harassment ended in the Broughton Archipelago in May 1999 and whale occurrence re-established to baseline levels. This study concludes that whale displacement resulted from the deliberate introduction of noise into their environment.
Summary • Human disturbance has been associated with declines in breeding success in numerous species and is of general concern to conservationists. However, the current framework for predicting and minimizing disturbance effects is weak and there is considerable uncertainty about why animals are disturbed by people in the first place. • We developed a behavioural model of perceived predation risk as a framework for understanding the effects of disturbance on cliff-nesting birds. This encompassed the concept that the effects of disturbance should increase with increasing numbers of visitors, and decrease with distance from the nest, an insight ignored in current conservation practice. • The predictions of this model were tested using field data on nesting success in two species of seabird, kittiwake Rissa tridactyla and guillemot Uria aalge. Statistical models of nesting success in both species suggested that perceived predation risk is a good predictor of the effects of disturbance. • Synthesis and applications. Our findings suggest that fixed set-back distances and buffer zones are likely to be inappropriate conservation measures in situations where the numbers of visitors to wildlife areas fluctuates spatially and temporally, as is generally the case. In managing access to wildlife areas there is a need to ensure that larger parties of visitors are kept further away from the nesting areas of vulnerable species or that set-back distances are determined for the largest party likely to visit the site. Journal of Applied Ecology (2004) 41, 335 –343
Johnstone Strait provides important summer habitat for the northern resident killer whales Orcinus orca of British Columbia. The site is also an active whale-watching area. A voluntary code of conduct requests that boats do not approach whales closer than 100 m to address perceived, rather than demonstrated, effects of boat traffic on killer whales. The purpose of the study was to test the relevance of this distance guideline. Relationships between boat traffic and whale behaviour were studied in 1995 and 1996 by shore-based theodolite tracking of 25 identifiable focal animals from the population of 209 whales. Individual killer whales were repeatedly tracked in the absence of boats and during approaches by a 5.2 m motorboat that paralleled each whale at 100 m. In addition, whales were tracked opportunistically, when no effort was made to manipulate boat traffic. Dive times, swim speeds, and surface-active behaviours such as breaching and spy-hopping were recorded. On average, male killer whales swam significantly faster than females. Whales responded to experimental approaches by adopting a less predictable path than observed during the preceding, no-boat period, although males and females used subtly different avoidance tactics. Females responded by swimming faster and increasing the angle between successive dives, whereas males maintained their speed and chose a smooth, but less direct, path. Canonical correlations between whale behaviour and vessel proximity are consistent with these conclusions, which suggest that weakening whale-watching guidelines, or not enforcing them, would result in higher levels of disturbance. High variability in whale behaviour underscores the importance of large sample size and extensive experimentation when assessing the impacts of human activity on killer whales.
This study examined the activities of “northern resident” killer whales (Orcinus orca) in Johnstone Strait, British Columbia, Canada, in July and August, from 1995 to 2002. Disturbance from boat traffic has been identified as a conservation concern for this population. The primary aims of the study were to test whether boat presence altered whales’ activities, and if so, to estimate whether behavioural responses were likely to have carried energetic costs. A land-based observation site near a vessel-exclusion marine protected area allowed us to conduct a natural experiment to monitor whale activities in the presence and absence of boats. Using Time-Discrete Markov Chain models, boat presence was linked to significant changes in the probability that focal whales would switch from one activity state to another, which led to significantly different activity budgets in the presence and absence of boats. We estimated that the energetic cost of meeting these budgets differed by only 3–4%. In the presence of boats, however, whales reduced their time spent feeding and the time spent rubbing their bodies on smooth pebble beaches. These lost feeding opportunities could have resulted in a substantial (18%) estimated decrease in energy intake. Our sensitivity analysis provides preliminary evidence that disturbance could carry higher costs to killer whales in terms of reducing energy acquisition than increasing energetic demand, and future research should address this directly. Meanwhile, our observations suggest that protected areas would confer greatest conservation benefit to endangered killer whale populations if they were designed to protect important foraging areas.
All cases of adenocarcinoma in the duodenum (n = 263) and jejunum/ileum (n = 663), diagnosed between 1960 and 1988, were recruited from the Swedish Cancer Registry. Corrected and overall survival were investigated by sex, age and year of diagnosis with life-table and Cox proportional hazards analyses. The corrected 5- and 10-year survival rates were 39% and 37% for duodenal tumours and 46% and 41% for those in jejunum/ileum (P = 0.16 for difference between sites). The corrected 5- and 10-year survival rates were 52% and 48% for women and 40% and 34% for men with tumours in jejunum/ileum (P = 0.0095 for difference by sex) while no such relation was found in duodenal tumours (P = 0.84). Survival correlated with age at diagnosis for duodenal tumours (P = 0.03377). A Cox proportional hazards analysis revealed a temporal trend with more favourable prognosis in recent years. This study confirms that prognosis of small bowel adenocarcinoma is serious, but gives a more optimistic outlook than many hitherto published series.
Background noise can interfere with the detection and discrimination of crucial signals among members of a species. Here we investigate the vocal behaviour in the presence and absence of whale-watcher boat traffic of three social groups (pods) of killer whales (Orcinus orca) living in the nearshore waters of Washington state. We find longer call durations in the presence of boats for all three pods, but only in recent recordings made following a period of increasing boat traffic. This result indicates that these whales adjust their behaviour to compensate for anthropogenic noise once it reaches a threshold level.
The soundwatch boater education program: trends in vessel traffic with southern resident killer whales
- K Koski
Koski, K. (2004). The soundwatch boater education program: trends in vessel traffic with southern resident killer whales.
Linking short and long-term effects of nature-based tourism on cetaceans The ecology of fear: optimal foraging, game theory, and trophic interactions
- L Bejder
- Canada
- J S Brown
- J W Laundre
- M Gurung
Bejder, L. (2005). Linking short and long-term effects of nature-based tourism on cetaceans. PhD thesis, Dalhousie University, Halifax, NS, Canada. Brown, J.S., Laundre, J.W. & Gurung, M. (1999). The ecology of fear: optimal foraging, game theory, and trophic interactions. J. Mammal. 80, 385–399.
The potential of whale watching in Europe. Bath: Whale and Dolphin Conservation Society. International Whaling Commission (cited as IWC)
- E Hoyt
Hoyt, E. (1997). The potential of whale watching in Europe. Bath: Whale and Dolphin Conservation Society. International Whaling Commission (cited as IWC). (2005).
Linking short and long-term effects of nature-based tourism on cetaceans
- L Bejder
Bejder, L. (2005). Linking short and long-term effects of
nature-based tourism on cetaceans. PhD thesis, Dalhousie
University, Halifax, NS, Canada.
Behavioral responses of humpback whales (Megaptera novaeangliae) to whalewatching boats near Isla de la Plata
- M Scheidat
- C Castro
- J Gonzales
- R Williams
Scheidat, M., Castro, C., Gonzales, J. & Williams, R. (2004).
Behavioral responses of humpback whales (Megaptera
novaeangliae) to whalewatching boats near Isla de la Plata,
Machalilla National Park, Ecuador. J. Cetacean Res.
Mgmt. 6, 63–68.
Behavioral responses of killer whales to whale‐watching traffic
- Williams R.
Managing the impacts of dolphin‐based tourism through the definition of critical habitats
- Lusseau D.
Wolves and the ecology of fear
- Ripple W.J.
Predation risk and microhabitat preference
- Formanowicz D.R.
Effects of predation risk on space by small mammals
- Lagos V.O.
The hidden cost of tourism
- Lusseau D.