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Nature-based tourism and the behaviour of bottlenose dolphins Tursiops spp. in Port Phillip Bay, Victoria, Australia
Abstract
Nature-based tourism targeting cetaceans is a billion dollar industry that continues to grow. Therefore, the ecological effects of this industry require investigation. Inshore marine wildlife, such as coastal populations of dolphins that have become tourism targets, is affected by human activities in the coastal zone, and tourism may be an additional stressor. The focus of marine wildlife tourism in southern Port Phillip Bay, Victoria, Australia, is a coastal population of bottlenose dolphins (Tursiops spp.). Commercial dolphin-swim and dolphin-watch operations seek out dolphins. This study monitored activity budgets of bottlenose dolphins at one site, in the presence and absence of vessels during a two-year period through land-based observations. The results demonstrate a significant decreased likelihood of bottlenose dolphins engaging in feeding behaviour when vessels were present. Schools with calves were significantly larger than groups without and vessel presence resulted in larger schools regardless of school composition. Results also indicated that the number of dolphins observed at the study site were lower during afternoon ebb tides and on afternoon slack tides. The significance of their reduced feeding in the long-term conservation of these dolphins will remain unclear until information is available on their behaviour in areas into which tourist operators do not venture.
... While these experiences provide visitors with the up-close interaction they desire, the negative impacts to dolphins can be numerous (see Section 4.0). As dolphins are social animals, many aspects of their natural behaviour can be interrupted by the impacts of tourism (Orams 2002;Scarpaci, Nugegoda and Corkeron 2010;Steckenreuter, Möller and Harcourt 2012). A conceptual model for the tensions associated with the feeding of wild dolphins for tourism is provided by Figure 1. the feeding of wild dolphins to enhance the tourism experience contrasted with the tension between feeding and visitor concern for dolphin welfare. ...
... The time spent resting, feeding, and socialising are important activities for reproductive success in dolphins (Peters et al. 2013). One of the most commonly studied impacts of human-dolphin interactions concerns how boat traffic associated with dolphin watching and swim-with experiences affects the time wild dolphins spend foraging (Dans et al. 2008;Meissner et al. 2015;Scarpaci et al. 2010;Wiener 2015). The contradictory studies of Steckenreuter et al. (2012) and Trone, Kuczaj and Solangi (2005), among others, illustrate the complexity of studying the impacts that arise due to interactions between wild dolphins and tourist boats. ...
... Many authors describe the impacts of feeding on the social behaviour of wild dolphins, which are ecologically important as dolphins feed and live in social groups, and it has been reported that some provisioned dolphins have even become solitary animals (Dans et al. 2008;Orams 1997;Scarpaci et al. 2010). ...
... Studies showed that Bottlenose dolphins' feeding behaviour was significantly affected when tour vessels were present. Their whistling increased to maintain group cohesion, and the long-term effects of this impact remain unclear (Scarpaci et al., 2000(Scarpaci et al., , 2010. The Dolphin Research Institute (DRI) classified dolphins' responses when approaching a vessel into the three categories of interaction, avoidance and neutral (Dunn et al., 2001). ...
... The results indicated that Bottlenose dolphins were significantly less likely to feed when vessels were present. The pods with calves were larger than those without, but all pods increased in size when vessels were present (D6, figure 1; Scarpaci et al., 2010). Howes et al. (2012) evaluated the effectiveness of the Ticonderoga Bay Sanctuary Zone. ...
With the rapid growth of whale-watching tourism, the importance of its management has become evident. Higham and colleagues indicated that adaptive management is the key to a sustainable whale-watching industry and proposed an integrated and adaptive management model, combining stakeholder perspectives and operating in a dynamic two-phase environment. This study applies the model to whale-watching tourism management in Port Philip Bay (Australia) examining the extent of its fit in this case study, and what management measures could be adopted to achieve sustainable development of whale-watching tourism. This study obtained secondary data to analyse the responses of target species to tourism activities and management strategies adopted since the inception of whale-watching tourism. A key outcome is the development of sustainable management for whale-watching tourism. As the tourism industry waits to recover from the COVID-19 pandemic, such a rethink has implications for the shift towards more holistic sustainability and resilience of whale-watching tourism post-COVID-19.
KeywordsSustainable ManagementWhale-Watching TourismPort Phillip Bay
... Thus, these dolphins likely expend greater levels of time and energy during SWD tourism interactions, with possible missed opportunities for foraging and socialising (including mating, Filby et al. 2014). This is of concern, given recent research indicating that PPB is an important foraging and nursery ground for Burrunan dolphins (Scarpaci et al. 2010, Filby et al. 2017) and that groups containing calves are those most likely to avoid SWD vessels (Filby et al. 2014). ...
... The time series of behavioural states resulting from each focal follow was first tallied into 2 contingency tables, one for control and one for impact scenarios. From the resulting matrices, the transition probability between the preceding behavioural state and the succeeding behavioural state was estimated (Lusseau 2003a, Christiansen et al. 2010 Shane et al. 1986, Scarpaci et al. 2010, Filby et al. 2013 lations, see the 'Transition probabilities' section in the Supplement at www. int-res.com/ articles/ suppl/ n032 p479 _ supp. ...
Burrunan dolphins Tursiops australis are frequently targeted by tourism operations in Port Phillip Bay, Australia. This study aimed to provide first insights into whether swim-with-dolphin vessels in Port Phillip Bay affect the behaviour of Burrunan dolphins via the use of Markov chain models. The presence of swim-with-dolphin vessels affected dolphins’ travelling, foraging, milling and socialising behaviours. The time Burrunan dolphins spent foraging in the presence of swim-with-dolphin vessels was significantly reduced, with average foraging bout length decreasing by 13.6%, foraging recovery time increasing by 47.6%, and the probability of transitioning from foraging to milling increasing 4-fold. Conversely, dolphins spent significantly more time milling and socialising in the presence of swim-with-dolphin vessels. The reduction in time spent foraging when swim-with-dolphin vessels are present could lead to a decrease in dolphins’ rate of energy acquisition, whilst the increase in milling could increase their energy expenditure. Collectively, this may lead to reduced biological fitness with population level consequences. However, although the short-term behavioural budget of the dolphin population was significantly affected, swim-with-dolphin vessels did not significantly affect the cumulative (i.e. yearly) behavioural budget of Burrunan dolphins. Thus, the assumption that boat-based cetacean tourism has major negative effects on targeted populations may be flawed.
... Thus, these dolphins likely expend greater levels of time and energy during SWD tourism interactions, with possible missed opportunities for foraging and socialising (including mating, Filby et al. 2014). This is of concern, given recent research indicating that PPB is an important foraging and nursery ground for Burrunan dolphins (Scarpaci et al. 2010, Filby et al. 2017) and that groups containing calves are those most likely to avoid SWD vessels (Filby et al. 2014). ...
... The time series of behavioural states resulting from each focal follow was first tallied into 2 contingency tables, one for control and one for impact scenarios. From the resulting matrices, the transition probability between the preceding behavioural state and the succeeding behavioural state was estimated (Lusseau 2003a, Christiansen et al. 2010 Shane et al. 1986, Scarpaci et al. 2010, Filby et al. 2013 lations, see the 'Transition probabilities' section in the Supplement at www. int-res.com/ articles/ suppl/ n032 p479 _ supp. ...
Marine Protected Areas (MPAs) are increasingly used to protect marine mammals from anthropogenic threats despite limited studies that assess their efficacy. The small population of Burrunan dolphins (Tursiops australis) that inhabit Port Phillip Bay (PPB), Australia, are genetically isolated, listed as threatened and are exposed to dolphin-swim tourism. This study aimed to identify areas within PPB where dolphins are most likely to rest, forage and socialise, and whether these behaviours occur frequently within Ticonderoga Bay Sanctuary Zone (TBSZ), the only protected area designated for dolphins within PPB. Here, a comprehensive activity budget for Burrunan dolphins was established and critical habitat identified. Behavioural data were collected from 51 independent dolphin groups during 67 boat-based surveys conducted in southern PPB between December 2009 and May 2013. Travel (63.9%) and rest (1.8%) were the most and least frequently observed behaviours, respectively. Forage (16.4%), mill (10.8%) and social (7.2%) accounted for the remainder of the activity budget. Results indicate that the broader PPB region is important for foraging, socialising and nursing dolphins, while TBSZ has proven importance for foraging dolphins. Thus, the implementation of TBSZ was a correct management decision and MPAs developed without baseline data can be effective for marine mammal conservation. Three candidate MPAs were objectively identified in areas that are hotspots for foraging and socialising Burrunan dolphins in southern PPB. The findings of this study will be used to inform current conservation management strategies. If implemented, the aim of the proposed MPAs will be to reduce impacts from anthropogenic disturbance, namely dolphin-swim tour vessels.
... Avoidance behaviours, or transition between behaviours have been recorded, including the cessation of feeding or resting (e.g. Williams et al., 2002a,b;Williams, 2011;Constantine et al., 2003Constantine et al., , 2004Coscarella et al., 2003;Lusseau, 2003Lusseau, , 2004Lusseau, , 2006Jahoda et al., 2003;Ö stman-Lind et al., 2004;Samuels and Bejder, 2004;Scheidat et al., 2004;Bejder et al., 2006;Lemon et al., 2006;Richter et al., 2006;Underhill, 2006;Morete et al., 2007;Yazdi, 2007;Arcangeli and Crosti, 2009;Christiansen et al., 2010;Scarpaci et al., 2010;Schaffar et al., 2009Schaffar et al., , 2013Stamation et al., 2009;Steckenreuter et al., 2011Steckenreuter et al., , 2012Montero-Cordero and Lobo, 2010;Lundquist, 2011;Visser et al., 2011;Lundquist et al., 2012;Steckenreuter et al., 2012;Machernis, 2014;Symons et al., 2014;Patroni et al., 2019;Sprogis et al., 2020). Repeated vessel interactions could make these reactions, though typically only observed in the direct presence of vessels, have a more significant outcome to both individual and population success than is currently considered (e.g. ...
The interactions between wildlife tourism operators and the animals that they rely on are complex. For commercial whale watching, the recognition of the potential disturbance from the vessels generates uncertainty regarding the effectiveness of management strategies for it to remain a ‘no-take’ practice. This warrants further evaluation. In this study, we analysed the activities of the whale watching fleet in Tofino, Vancouver Island, British Columbia, Canada, to evaluate industry sustainability and its ability to meet legislated conservation objectives. Visual observations gave context to an analysis of the communications of the fleet, made using Very High Frequency (VHF) marine radio. Transcription of these communications demonstrated three main themes; whale location, whale ‘transfers’ between operators, and encounter or ‘show’ quality. Cumulative encounter times from the fleet far exceeded the 30-minute limit recommended in the whale watching guidelines. Killer whales (Orcinus orca) were subject to the longest periods of vessel presence, with an average time spent in active encounters of 4.21 ±1.96 hours. This extended to almost the full operating day if whales remained within a feasible travelling distance of Tofino. Humpback (Megaptera novaeangliae) and gray whale (Eschrichtius robustus) encounters also exceeded the suggested time limit by 2.40 ± 1.73 hours and 1.31 ±1.07 hours, respectively. Increased education and the addition of spatial and temporal restrictions in management regimes could address the shortcomings of the current system to minimize potential disturbance to whales from commercial whale watching encounters and facilitate sustainable industry practices.
... Avoidance behaviours, or transition between behaviours have been recorded, including the cessation of feeding or resting (e.g. Williams et al., 2002a,b;Williams, 2011;Constantine et al., 2003Constantine et al., , 2004Coscarella et al., 2003;Lusseau, 2003Lusseau, , 2004Lusseau, , 2006Jahoda et al., 2003;Ö stman-Lind et al., 2004;Samuels and Bejder, 2004;Scheidat et al., 2004;Bejder et al., 2006;Lemon et al., 2006;Richter et al., 2006;Underhill, 2006;Morete et al., 2007;Yazdi, 2007;Arcangeli and Crosti, 2009;Christiansen et al., 2010;Scarpaci et al., 2010;Schaffar et al., 2009Schaffar et al., , 2013Stamation et al., 2009;Steckenreuter et al., 2011Steckenreuter et al., , 2012Montero-Cordero and Lobo, 2010;Lundquist, 2011;Visser et al., 2011;Lundquist et al., 2012;Steckenreuter et al., 2012;Machernis, 2014;Symons et al., 2014;Patroni et al., 2019;Sprogis et al., 2020). Repeated vessel interactions could make these reactions, though typically only observed in the direct presence of vessels, have a more significant outcome to both individual and population success than is currently considered (e.g. ...
Recognition of the potential disturbance from whale-based tourism has stimulated the discussion of whether whale watching remains ‘no take’. Here we use observations and passive acoustic surveillance of tourism activities of foraging gray whales (Eschrichtius robustus) on the west coast of Vancouver Island to better understand the pressures on whales that are repeatedly subject to aerial and vessel-based viewing. Pressure from the fleet was greatest for low prey years, whereby fewer whales were subject to a greater number of encounters with whale watching vessels. The pressure on operators for close encounters was also greater during these years. The acoustic recordings found that whale watching vessels shaped the soundscape, with a distinct diurnal pattern. Acoustic reactions by the whales were also noted. Cow-calf pairs showed increased calling rate in the presence of vessels in the feeding bay, with calling rate of single foraging whales increasing as vessel number, particularly those engaged in whale watching, increased. These responses have implications for energetics, communication success. The implications of acoustic disturbance from whale watching has yet to be well defined, but it is only one of many stressors that gray whales are subject to. The results of this study lead us to argue for greater evidence-based management of whale watching; restrictions on encounters; noise emission limitations; requiems for the whales, and a greater interpretative component for passengers. The aggregate and cumulative effects of disturbance should also be emphasized in vessel-whale interaction guidelines, with the most vulnerable individuals removed from the viewing resource altogether.
... Port Phillip supports a resident population of 80-100 bottlenose dolphins that have been the subject of considerable study in recent decades by the Dolphin Research Institute and by geneticists based at Monash University. These studies have focused on behaviour, distribution and population processes (Scarpaci et al. 2003), the impact of 'swim with the dolphins' tourism (Scarpaci et al. 2010), and on the taxonomic identity of the dolphins. Importantly, the Port Phillip bottlenose dolphins belong to a newly described species that also occurs in sub-populations in a few shallow embayments across southern Australia, including the Gippsland Lakes (Charlton-Robb et al. 2011). ...
We collated and analysed records of mammal species (native and introduced) from across 32 Local Government Areas that comprise the Greater Melbourne region. Records of each species were examined for temporal changes in presence or absence. The region has a particularly diverse mammalian fauna with records of 92 species, including 19 marine mammals that have been recorded in Port Phillip. This total represents 65% of Victoria's mammalian fauna. About one-third of the 51 native terrestrial species have undergone a demonstrable decline in the region, to the point where their future presence is in doubt. Five species are no longer found in the region and the status of another three is uncertain. In contrast, up to five native terrestrial species are thought to have increased in abundance in recent decades, including the spectacular colonisation of the city by the Grey-headed Flying-fox as a year-round resident.
... As in many humpback whale populations [6], individuals in the Oceania population are known to respond to disturbance, showing increases in dive time and decreased linearity of swim path when boats are within 1000 m of whales [7]. More generally, swim-with cetacean programs have been shown to increase individuals' travel speed, reorientation rates, surface activity, time spent travelling, and avoidance responses, and reduce time spent feeding [8][9][10][11][12][13][14]. Mother/calf pairs are the most likely to be disturbed [15]. ...
The Oceania population of humpback whales (Megaptera novaeangliae) using Tongan waters is a listed Endangered subpopulation that supports a large swim-with whale industry focussed primarily on mothers and calves. This raises concerns about the industry's potential to impact on the subpopulation's breeding success and recovery. This study investigated whether whales responded differently to approaches by swimmers from boats than to boat approaches alone and whether different types of swimming (quiet approach, loud splashing or diving following a quiet approach) induced different avoidance responses. An avoidance response was defined as whales moving away from boats or swimmers and the strength of the response was defined by how far the whales moved away and whether there was an increase in surface activity. Animals responded more quickly to a loud splashing approach than to quiet approaches. There were no significant differences in measures relating to the strength of the response caused by swim type, however closer approaches by a boat did significantly increase the level of whale activity. These results suggest that managing swimmer behaviour around whales, particularly ensuring quiet approaches, will contribute to the ability of the industry to minimise disturbance of the animals and support the industry's sustainability.
... Recent research (Scarpaci, Nugegoda, & Corkeron, 2010), supports the TBSZ as an important dolphin foraging ground and the recent discovery that this relatively small dolphin population is one of only two known endemic populations of T. australis sp. nov. ...
Over the past two decades, considerable growth in commercial cetacean-based tourism has exposed coastal cetacean populations to high vessel density. Since 1989, Port Phillip Bay, Victoria, Australia, has hosted a thriving dolphin-swim tourism industry comprised of three licensed vessels. This study assessed the effectiveness of the Ticonderoga Bay Sanctuary Zone, a protected area enacted under the Wildlife (Whales) Regulations 1998, to serve the resident dolphins as an area of ‘respite’ and ‘refuge’ from anthropogenic stress, including commercial tourism. Research was conducted onboard 104 dolphin-swim tours, with both tour operation and dolphin school behaviour recorded using a combination of continuous observations and 1-min scan samples. During all observed encounters within the sanctuary zone, tour operations contravened the site-specific minimal approach distance regulation. By also contravening generic permit conditions (compliance range 0–70%) to the level of unsatisfactory compliance consistent with that documented outside the sanctuary zone, tour operations did not exercise any additional caution during a dolphin encounter within the sanctuary zone. Recommendations for this industry include a shift from sole reliance on passive management strategies to a judicious management plan that includes enforcement to support the governing regulations.
Vessels cause considerable disturbance to cetaceans world-wide, with potential long-term impacts to population viability. Here we present a comprehensive review of vessel impacts to cetacean behavior in Australian waters (2003–2015), finding inadequate protections to be in place. The majority of these studies found trends of decreased animal travel and resting behavioral states as well as low compliance to regulations, and they recommended further regulatory action such as greater enforcement or monitoring, or passive management strategies. As a case study, we conducted the first field assessment of vessel compliance with the Wildlife (Marine Mammal) Regulations 2009 in Gippsland Lakes, Australia, and provide the first assessment of the endangered Gippsland Lakes Burrunan dolphin ( Tursiops australis ) population’s behavioral ecology. Dolphin behavior and vessel regulation compliance data were collected during boat-based surveys of Gippsland Lakes from July 2017 to January 2018, with a total of 22 dolphin group sightings resulting in 477 five-minute point samples. 77% of dolphin sightings involved vessel interactions (within 400 m), and 56 regulation breaches were observed. These breaches were most severe in summer (mean = 4.54 breaches/hour). Vessels were found to alter dolphin behavior before, during, and after interactions and regulation breaches, including increased mating (mate guarding) and milling behavioral states, and increased ‘fish catch’, ‘high leap’ and ‘tail slap’ behavioral events. These behavioral changes may indicate masking of the dolphins' acoustic communication, disturbance of prey, increased dolphin transition behaviors, and/or induced stress and changes to group structure (including increased mate guarding). While our results provide evidence of short-term altered behavior, the potential for long-term effects on population dynamics for this threatened species is high. In the context of reported inadequate cetacean protection Australia-wide, our management recommendations include greater monitoring and enforcement, and the utilisation of adaptive management.
The purpose of this chapter is to discuss critically, based on a review of recent literature on the topic, the challenges faced by urban tourism destinations with regards to eTourism and new technologies.
Whale-watching research encompasses a wide variety of disciplines and fields of study, including monitoring the biological impacts of whale-watching activities on cetaceans and assessments of the effectiveness of whale-watching management and regulations, to the sociological and economic aspects of whale watching on communities hosting such activities. This article is the latest in a series of annual digests, which describes the variety and findings of whale-watching studies published over the past year, since June 2009.
Patterns of association among bottlenose dolphins resident in Shark Bay, Western Australia were analyzed using party membership data. Parties contained an average of 4.8 individuals, but party size and composition were unstable. While these temporary parties often contained both males and females, long term consistent associations generally were between members of the same sex. The highest association coefficients, resulting from very frequent co-occurrence within parties were between males and between mothers and offspring. Males formed subgroups of two or three individuals who consistently associated with each other, and these were stable over periods of at least seven years in some cases. Male subgroups preferentially associated with particular other male subgroups. Females associated most consistently with other females, although not to the same extent as some males. Female associations were better described as a network rather than discrete subgroups. Male-female associations were generally inconsistent and depended in part on female reproductive state. Mothers and their offspring associated very consistently for at least 4 years.
The ever-increasing tourist industry has extended to the aquatic environments, thus making the aquatic mammals susceptible to interactions with humans. Dolphin watching tourism has developed to a great extent in the Pipa Beach, Rio Grande do Norte, consequently the number of dolphin-watching boats operating in this area has increased. In the present study the behavioral alterations of Sotalia guianensis (Van Bénédén, 1864) caused by the presence of these boats were verified. Behavioral registers of S. guianensis were compiled from a fixed point on the cliffs close to the study area. The observations were effected when there were no boats, in the presence of boats and after the departure of boats. The results show that type of approach by the dolphin watching boats had a major influence on the behavior of the dolphins, especially so in the groups with calves. The short term impacts were rather discrete, however, new methods should be applied in order to verify the long term impacts on the dolphins.
Kepulauan Seribu was designated as a marine protected area to promote and protect a healthy marine ecosystem and its biodiversity. However, despite numerous efforts to protect the area, the park continues to be impacted by both external and internal factors. External factors include domestic sewage, vessel traffic, industrial effluent, and urban run-off from metropolitan Jakarta. Meanwhile, internal factors include the problems created by tourism development and the impacts of the economic activities of the park's residents. The ongoing political and economic crisis in Indonesia, which has plagued the country since 1997, has amplified the pressure on the resources and on the well being of the park. This study traces and analyzes the intrinsic causes of the internal problems using a socioeconomic perspective. We suggest that alleviation of poverty and marginality of the park's residents should be prioritized, and that park management should be based on consensus building and participation of all stakeholders.
This paper reports a case of collision between an individual spinner dolphin and a boat in the Fernando de Noronha Archipelago, as an example of disturbance potentially caused by tourism industry activities. Photos illustrating the inflicted injuries on the animal are presented, and preventive measures to avoid this kind of accidents are proposed. This is the first report on a collision between spinner dolphins and boats.
Humpback whales (Megaptera novaeangliae) were tracked from shore to determine habitat-use patterns in an area relatively undisturbed by human activity near the "Big Island" of Hawaii during the winter 1988 and 1989 calving seasons. The temporal and spatial distributions of whales differed with group size and composition. During afternoon hours, groups containing a calf occurred in water significantly shallower and nearer to shore than did groups without a calf. Late in the breeding season, the same segregation pattern occurred throughout the day. Between-groups distances were significantly greater for groups with a calf than distances between all other groups. The number of whales observed per hour peaked during mid-February, although the relative sighting rates for various group sizes and compositions varied across the breeding season. Adults without a calf may use deep water to facilitate breeding behavior, while maternal females may use shallower water to avoid harassment and injury to calves from sexually active males, turbulent offshore or deep sea conditions, or predators. The predominance of cows with a calf in coastal habitat increases their exposure to expanding human-related development and aquatic activities that could injure, disturb, or displace them.
Common dolphins Delphinus sp. are frequently targeted by tourism operations in New Zealand waters, yet there is a paucity of data on potential impacts faced by this species. Transition matrix models, used widely in population ecology, have recently been applied to behavioural transitions in order to provide successful management guidelines. We detail the use of Markov chain models to assess the impact of tourism activities on the behavioural state of common dolphins in the Hauraki Gulf, New Zealand. First-order time discrete Markov chain models were used to describe transition probabilities in both control and impact scenarios. The effect of boat interactions was quantified by comparing transition probabilities of both control and impact chains. Foraging and rest- ing bouts were significantly disrupted by boat interactions to a level that raises concern about the sustainability of this impact. Both the duration of bouts and the overall time spent in these 2 be- havioural states decreased. Foraging dolphins took significantly longer to return to their initial behavioural state in the presence of the tour boat. There was also an increased preference to shift behaviour to socialising or milling after tour boat interactions. Impacts identified in the present study are similar to those previously reported for bottlenose dolphins, a coastal species typically considered to be more susceptible to cumulative anthropogenic impacts.
The effects of the presence of vessels on the behaviour of humpback whales (Megaptera novaeangliae) was studied in Hervey Bay, Queensland, where southward-migrating whales are the focus of a commercial whale-watching industry. The behaviour of whales was observed from a small yacht under sail. Rates of occurrence of units of behaviour for entire pods were obtained from continuous sampling of pods. Pods without calves showed lower rates of behaviour generally when vessels were within 300 m of them. Pods both with and without calves were more likely to dive rather than slip under when vessels were within 300 m. Hybrid multidimensional scaling of rates of behaviours of pods indicated differences between suites of behaviours exhibited by pods when vessels were within 300 m of them and when they were not. Classification of the patterns of occurrence of behaviours demonstrated that for pods both with and without calves, different units of behaviour tended to occur together when vessels were within 300 m and when they were not. Whale watching offers a nonlethal commercial use of whales, but in Hervey Bay, whale watching affects the behaviour of whales, which, although migrating, can be involved in breeding ground activities. Whether the short-term behavioural changes described here are accompanied by longer term avoidance of Hervey Bay by humpback whales as they migrate south remains to be determined.
The impact of cetacean eco-tourism on subject animals is not clearly understood. Studies that monitor this impact have traditionally concentrated on observable surface behaviour despite the fact that sound is the primary communication channel for cetaceans. This study monitored whistle production in free ranging bottlenose dolphins (Tursiops truncatus) to evaluate if dolphins vocalise at different rates in response to commercial dolphin-swim boats. Thirty-two hours of sound were recorded in the austral spring and summer of 1995/96. Results indicate that whistle production is significantly greater in the presence of commercial dolphin swim boats, regardless of dolphinsﾒ behavioural state prior to the arrival of the vessels. The increase in whistle production suggests that group cohesion may be affected during approaches made by commercial dolphin swim tour-operators or may serve some other social function. Monitoring vocal behaviour offers another insight into short-term human impacts on cetaceans.
The social structure of animal communities is usually measured through interactions or associations of individuals within the community. However, investigating and identifying association patterns for large communities of social animals can be difficult, given the logistical difficulties of identifying a large number of individuals within a given area and time period. In this study, over 550 individuals were identified within a large community of bottlenose dolphins (Tursiops aduncus) sampled intensively during the winters of 1998 and 1999 off Point Lookout, Queensland, Australia. Association patterns within this community were analysed using the half-weight index of association, including seven criteria for selecting individuals for inclusion in the analysis. Selection criteria were based on the number of times an individual was sighted during the entire study period. Overall, the community showed a highly fluid association pattern, with only two selection criteria showing association patterns that differed significantly from random. This type of association pattern is commonly reported for large communities of cetaceans. However, without the inclusion of other population information such as estimates of the proportion of identifiable individuals in the community and of community size, it appears that association patterns for these large communities may not be accurately assessed.
This article reports on operator compliance with regulations regarding humans swimming with free-ranging bottlenose dolphins (Tursiops sp.) in Port Phillip Bay, Victoria, Australia. The objective of this study was to compare if the level of compliance to three conditions (approach type, swim time, and time in proximity to dolphins) in the tour operators' permits changed after state government conducted a review on the existing operators. An additional fourth condition (number of swimmers participating in a dolphin-swim) was also studied. A total of 128 commercial dolphin-swim trips from September 1998–April 1999 and September 1999–April 2000 (prereview) and 16 commercial dolphin-swim trips from February–March 2002 and January 2003 (postreview) were studied. Data were collected using 1-minute scan samples and continuous observations from all three operating human–dolphin-swim tourist vessels. There was no detectable change in the level of compliance for rules regarding the way boats approached dolphins, their time in the proximity of dolphins, and the length of time people swam with dolphins. Operators always complied with regulations regarding the number of people participating in a dolphin-swim. Investigations of the extent to which tourism affects cetaceans have tended to ignore whether tourist vessels obey existing regulations. This study demonstrates that compliance cannot be assumed, and that operators appear to comply better with conditions that are easily quantified. Further, studies are needed to determine the statistical power required to detect changes in tour operator behavior to conditions in their permits. This will inform agencies whether the changes they have implemented to improve compliance levels are actually working.
The greatest source of human-related mortality for endangered Florida manatees is collisions with watercraft. Regulation of boat speeds is the principal management tool to minimize this threat. Demands on law enforcement limit their ability to monitor boater behavior and managers seek alternative strategies to increase compliance. The purposes of this study were to: (1) explore the effectiveness of an on-site sign to enhance boater compliance in a boating speed zone, and (2) examine the environmental and boating characteristics that influence the probability of compliance. Signs designed to increase compliance were posted halfway through the 18-week study period. The signs were not related to compliance level. Logistic regression models showed that only time of day and boat type were significantly related to compliance. Results suggest that passive methods of persuasion may not be an effective means of influencing boater behavior.
Population biology and socio-ecology of Indo-Pacific humpback dolphins Sousa chinensis were investigated during a 3-year study period in the Algoa Bay region, South Africa. The dolphins inhabit a narrow strip of coastal waters, mostly less than 15 m deep. Groups are small (mean=7 animals) and their daily activities concentrate around shallow rocky reefs—the primary feeding grounds. Dependence on these restricted, shallow-water habitats is evident throughout the year. Site fidelity is generally weak and is subject to seasonal migration, although female site fidelity seems to be related to reproductive stage. Births occur predominantly in summer. The social system is highly fluid, structured to some degree by sex and age, ‘mate-searching’ behaviour being the most likely male reproductive strategy. The dolphins inhabiting Algoa Bay are part of a substantially larger population that uses a considerable length of the coastal zone. Estimated population parameters are generally low, as are modelled population growth rates, and an increase in the population size seems unlikely. Humpback dolphins appear to be vulnerable to negative environmental pressure and the alteration/destruction of inshore habitats is probably among the greatest threats to them. Conservation of this species should be given high priority and be seen as an important part of integrated coastal zone management. Establishment of multiple-use management areas with controlled ecotourism and several priority sites declared as strict reserves seems to be the most effective conservation approach. In order to be successful, conservation and management policies need to recognize the needs and lifestyles of the local inhabitants.
This study represents the first long-term small mammal survey of the mid-altitude rain forest reserve of Analamazaotra, Madagascar. Twenty-three visits were made to the reserve between April 1988 and May 1990. Live-trapping with Sherman and pitfall traps at four sites subjected to varying levels of human disturbance revealed the presence of seven endemic tenrec species, three endemic rodent species and an introduced rat. Greater species richness was demonstrated at the most undisturbed site, though individual species abundance was reduced. Human disturbance associated with tourism was correlated with a decrease in endemic species richness and an increase in abundance of introduced rats. Forest subjected to infrequent logging by local people exhibited an intermediate level of species richness. It is recommended that core areas of the reserve be left undisturbed in order to preserve small mammal species diversity.
Two contrasting results emerge from comparisons of the social systems of several odontocetes with terrestrial mammals. Researchers have identified remarkable convergence in prominent features of the social systems of odontocetes such as the sperm whale and bottlenose dolphin with a few well-known terrestrial mammals such as the elephant and chimpanzee. In contrast, studies on killer whales and Baird's beaked whale reveal novel social solutions to aquatic living. The combination of convergent and novel features in odontocete social systems promise a more general understanding of the ecological determinants of social systems in both terrestrial and aquatic habitats, as well as the relationship between relative brain size and social evolution.
Very little is known about the acoustic repertoire of the Pacific humpback dolphin Sousa chinensis. This study, off eastern Australia, used concurrent observations of surface behaviour and acoustic recordings to gain an insight into the behavioural significance of humpback dolphin vocalizations. Humpback dolphins exhibit five different vocalization categories: broad band clicks; barks; quacks; grunts; and whistles. Broad band clicks were high in frequency (8 kHz to > 22 kHz), were directly related to foraging behaviour and may play a role in social behaviour. Barks and quacks were burst pulse sounds (frequency: 0.6 kHz to > 22 kHz, duration: 0.1-8 s) and were associated with both foraging and social behaviour. The grunt vocalization is a low frequency narrow band sound (frequency 0.5-2.6 kHz, duration 0.06-2 s) and was only heard during socializing. There were 17 different types of whistles, ranging widely in frequency (0.9-22 kHz) and vocal structure (n = 329), The predominant whistle types used by the groups were type 1 (46%) and type 2 (17%). Most whistles were heard during both socializing and foraging. The number of whistles recorded in a group increased significantly as the number of mother-calf pairs increased, suggesting that whistles may be used as contact calls. Few vocalizations were heard during either travelling or milling behaviours. Broad band clicks, barks and whistle type 1 were the only vocalizations recorded during either travelling or milling.
Behavioral responses by Sotalia guianensis dolphins in the presence of touristic sea traffic in the bay of Curral, Pipa-RN, Brazil, were measured. The dolphins changed their behavior when boats were closer than 100 meters. The main behavioral alterations were that the dolphins remained submerged for longer and that they formed a more cohesive group as the boats came closer. Although we concluded that the approach of the boats changed the dolphins’ behavioral pattern, we do not know what aspects of the boats caused the avoidance. We believe that the noise of the boats is probably responsible for repelling the animals.
Managing the activities of commercial wildlife viewing tends to involve either restricting the number of industry participants and/or regulating the activities or industry participants. We report on operator compliance with regulations regarding humans swimming with free-ranging bottlenose dolphins ( Tursiops sp.) in Port Phillip Bay, Victoria, Australia. A total of 128 commercial dolphin-swim trips was studied between September 1998 and April 2000. Four permit conditions were investigated: approach type, swim time, time in proximity of dolphins, and presence of "fetal fold" calves. Results demonstrate noncompliance by operators to all of the four permit conditions studied. Compliance with temporal conditions was poorer than with other conditions. When conducting studies on the extent to which tourism affects cetaceans, investigators should consider whether tourist operations comply with existing regulations or guidelines.
Ecological extinction caused by overfishing precedes all other pervasive
human disturbance to coastal ecosystems, including pollution, degradation
of water quality, and anthropogenic climate change. Historical abundances
of large consumer species were fantastically large in comparison
with recent observations. Paleoecological, archaeological, and historical
data show that time lags of decades to centuries occurred between the
onset of overfishing and consequent changes in ecological communities,
because unfished species of similar trophic level assumed the ecological
roles of overfished species until they too were overfished or died of
epidemic diseases related to overcrowding. Retrospective data not only
help to clarify underlying causes and rates of ecological change, but they
also demonstrate achievable goals for restoration and management of
coastal ecosystems that could not even be contemplated based on the
limited perspective of recent observations alone.
In the debt-ridden, high-population-growth, resource-mining states of the Congo Basin, conservation of biodiversity is seldom the primary concern of national policy makers or of local resource users. Moreover, the recurring costs of managing protected areas and the opportunity costs of forgoing logging and farming to maintain protected areas are a substantial net drain on national and local economies. Consequently, it is becoming increasingly important that protected areas generate, from user fees or donor contributions, sufficient funds to offset the costs of maintaining them. Government and donor investment currently meet less than 30 per cent of the estimated recurring costs required to manage the protected-area network within central African countries effectively, and cover none of the growing opportunity costs. Nature tourism, the fastest growing sector of the $US3 trillion (3 million million) a year global tourism, industry, may offer a source of revenue to help fill this gap in funds. Congo Basin national parks and reserves harbour many charismatic animals (okapi, lowland gorilla, mandrills, bongo, forest elephant) that are likely to attract tourists, and as a result many protected-area managers are sinking capital into the development of tourist infrastructure. This paper reviews the evidence for ecotourism's capacity to generate revenue for protected-area management and appraises the financial viability of nature tourism in the Congo Basin.
Excluding motor boats from small experimental plots in a lake with heavy boat traffic significantly increased macrophyte biomass, coverage, and shoot height compared to impacted areas. Lakes across the country are increasingly threatened by overuse, particularly involving more and larger motor boats. In recent years, Lake Ripley, located in Jefferson County in southern Wisconsin, has exhibited a decline in macrophyte abundance along with increased motor boat activity. To examine the possible connections between these two events, a study on the effects of motor boats on submerged aquatic macrophytes was conducted during the summer of 1995. Four enclosures, two of solid plastic and two of mesh fencing, were built in each of two areas in about 1 m of water adjacent to high boat traffic areas. These enclosures were intended to exclude motor boat access and, in the solid-walled enclosures, to block the turbidity generated by boat-induced sediment resuspension. Weekly water samples were collected for turbidity, suspended solids, dissolved oxygen, and temperature. At the end of the study, plant biomass, height and percent cover were measured inside the enclosures and in control plots. Our hypothesis was that motor boats limit macrophyte growth either directly by physical disturbance or more indirectly by generating turbidity which decreases light availability and therefore limits production and biomass. Results indicated that motor boats reduced plant biomass quite dramatically, primarily through scouring of the sediment substrate and direct cutting, but not through turbidity generation.
Recreational diving and snorkelling are increasingly popular leisure activities, with potentially adverse consequences for coral reefs and other types of marine life. This case study presents observations of the impact and management of visitors viewing a single animal species, the Southern Stingray (Dasyatis americana) congregating at a specific location (nicknamed 'Stingray City') off the coast of Grand Cayman in the western Caribbean. It is estimated that the stingrays now receive 80,000 to 100,000 visitors per year, and on a busy day more than 500 divers and snorkellers can be observed in the water stroking and feeding the rays. The stingray population is beginning to show major behavioural changes such as the development of shoaling behaviour, skin abrasion from handling, and altered feeding habits. It is also possible that some behavioural modifications are being learnt and transmitted to new generations of rays. Concern is expressed about the effect of consistently high levels of visitation upon the stingray population, and it is suggested that there is an urgent need for long-term monitoring with possible restriction of visitor numbers.
Tourism is now the world's largest industry, generating earnings of £285 billion/annum. In recent years, the tourism sector has become a significant contributor to the wealth of the UK and represents about 7% of the workforce. Greater mobility and more leisure time has led to greater car use, many more short-term movements of people, and increasing pressure on the transport infrastructure. Consequently, there is real concern about the effect of increased tourist activity on the environment and how the challenge of sustainable tourism can be achieved. This paper examines how the tourism industry is addressing that challenge by balancing the benefits of tourist activity without compromising the environment. In Wales, the Wales Tourist Board is committed to sustainable tourism, and its approach is offered as an example of achievement and how conflicting demands can be resolved.
Surveys on migratory waterbirds and their habitats at Lashihai Lake, China, were conducted from October 1999 to April 2000. Five fixed points, representing different degrees of habitat disturbance and quality, were selected around the lake. We used counts (n=30) to compare diversity and abundance of waterbirds at each point and evaluate the effects of habitat disturbance. The distribution of waterbirds was affected by disturbance, with more than one-third of the total species and nearly half of the total individuals occurring at the least disturbed point. Species richness was weakly and abundance was strongly correlated to habitat disturbance, but not to habitat quality. Habitat destruction and use of canoes were prominent at the lake. Naxi ethnic fishermen (n=37) were interviewed. They caught 570 waterbirds between October 1999 and March 2000 in fishing nets. An estimation of the total number of waterbirds been trapped on the lake is 6164. Diving species were most susceptible. Conservation measures that should implement immediately include the cessation of habitat destruction, better plan for the development of tourism, a reduction in the number of canoes and zoning of the non-fishing area.
A bstract
The responses of wild, non‐provisioned bottlenose dolphins ( Tursiops truncatus ) to swim attempts from commercial swim‐with‐dolphin tour boats were systematically observed during two research periods: 1994–1995 and 1997–1998. A total of 255 groups of dolphins was encountered during boat‐based surveys and 36% ( n = 93) were exposed to at least one swim attempt. The operators' success with swim attempts, defined as at least one dolphin milling within 5 m of at least one swimmer, decreased from 48% in 1994–1995 to 34% in 1997–1998, and avoidance responses to swimmers increased from 22% to 31%. Dolphin response was found to vary according to swimmer placement. The greatest increase in avoidance occurred when swimmers were placed in the dolphins' path of travel. Based on sighting records of 266 individually identified dolphins, it was estimated that an average dolphin was exposed to 31 swim attempts per year. This level of exposure suggests that individual dolphins have, with cumulative experience, become sensitized to swim attempts. When a swim attempt was successful, on average it involved 19% of the group. Age‐class differences in interaction rates showed that juveniles were significantly more likely to interact with swimmers than adults. This study highlights the importance of longitudinal studies in evaluating human impact and suggests the urgent need for similar studies of potential human impact on other toothed cetaceans.
Bottom trawling and use of other mobile fishing gear have effects on the seabed that resemble forest clearcutting, a terrestrial disturbance recognized as a major threat to biological diversity and economic sustainability. Structures in marine benthic communities are generally much smaller than those in forests, but structural complexity is no less important to their biodiversity. Use of mobile fishing gear crushes, buries, and exposes marine animals and structures on and in the substratum, sharply reducing structural diversity. Its severity is roughly comparable to other natural and anthropogenic marine disturbances. It also alters biogeochemical cycles, perhaps even globally. Recovery after disturbance is often slow because recruitment is patchy and growth to maturity takes years, decades, or more for some structure-forming species. Trawling and dredging are especially problematic where the return interval—the time from one dredging or trawling event to the next—is shorter than the time it takes for the ecosystem to recover; extensive areas can be trawled 100–700% per year or more. The effects of mobile fishing gear on biodiversity are most severe where natural disturbance is least prevalent, particularly on the outer continental shelf and slope, where storm-wave damage is negligible and biological processes, including growth, tend to be slow. Recent advances in fishing technology (e.g., rockhopper gear, global positioning systems, fish finders) have all but eliminated what were de facto refuges from trawling. The frequency of trawling (in percentage of the continental shelf trawled per year) is orders of magnitude higher than other severe seabed disturbances, annually covering an area equivalent to perhaps half of the world’s continental shelf, or 150 times the land area that is clearcut yearly. Mobile fishing gear can have large and long-lasting effects on benthic communities, including young stages of commercially important fishes, although some species benefit when structural complexity is reduced. These findings are crucial for implementation of “Essential Fish Habitat” provisions of the U.S. Magnuson-Stevens Fishery Conservation and Management Act which aim to protect nursery and feeding habitat for commercial fishes. Using a precautionary approach to management, modifying fishing methods, and creating refuges free of mobile fishing gear are ways to reduce effects on biological diversity and commercial fish habitat.
Perturbaciones del Lecho Marino por Artes de Pesca Móbiles: Una Comparación con la Tala Forestals
Los arrastres de fondo y el uso de otras artes de pesca móviles tienen efectos en el lecho marino que se asemejan a la tala total de bosques, que es a su vez una pertubación terrestre reconocida como una de las mayores amenazas a la diversidad biológica y la sustentabilidad económica. Las estructuras en comunidades marinas bénticas son generalmente mucho más pequeñas que aquellas en los bosques, pero la complejidad estructural no es menos importante que la biodiversidad. El uso de artes de pesca móviles quiebra, sepulta y expone animales marinos y estructuras sobre y en el substrato, reduciendo marcadamente la diversidad estructural. Su severidad es burdamente comparable con otras perturbaciones marinas de orden natural o antropogénico. Tambien altera los ciclos biogeoquímicos, de hecho a nivel mundial. La recuperación después de una pertubación es frecuentemente lenta debido a que el reclutamiento es por parches y el crecimiento para alcanzar la madurez toma años, décadas o aún más para algunas especies que forman estructuras. Los arrastres de fondo y dragados son especialmente problemáticos donde el intervalo de retorno (tiempo entre un evento de dragado o arrastre y otro) es más corto que el tiempo que toma a un ecosistema recuperarse;árears extensas son arrastradas entre un 100 y 700% por año o mas. Los efectos de las artes de pesca móviles en la biodiversidad son más severos cuando las perturbaciones naturales son menos prevalentes, particularmente en las afueras de la plataforma continental y la pendiente, donde el daño del oleaje por tormentas es negligible y los procesos biológicos (incluyendo crecimiento) tienden a ser lentos. Recientes avances en tecnología pesquera (e.g., sistemas de posicionamiento global, detectores de peces) aparentemente tienen todo, pero eliminan lo que de facto fueran refugios contra arrastres. La frecuencia de los arrastres (en porcentaje de la plataforma continental arrastrada por año) es órdenes de magnitud mayor que otras perturbaciones severas al lecho marino, anualmente la cobertura de área es equivalente quizá a la mitad de la plataforma continental marina, o 150 veces el área de tierra que es talada anualmente. Las artes de pesca móviles pueden tener impactos grandes y de larga duración en las comunidades bentónicas, incluyendo estadios jóvenes de peces de importancia comercial, aunque algunas especies se benefician cuando la complejidad estructural es reducida. Estos descubrimientos son cruciales para la implementación de el “hábitat esencial para peces” del Acta de Conservación y Manejo de Pesquerias Magnuson-Stevens de los Estados Unidos y que pretende establecer hábitats de reproducción y alimentación para peces comerciales. El uso de una aproximación precautoria de manejo, la modificación de métodos de pesca y la creación de refugios libres de artes de pesca móviles son formas para reducir los efectos en la diversidad biológica y el hábitat para peces comerciales.
A bstract
Behavioral scientists have developed methods for sampling behavior in order to reduce observational biases and to facilitate comparisons between studies. A review of 74 cetacean behavioral field studies published from 1989 to 1995 in Marine Mammal Science and The Canadian Journal of Zoology suggests that cetacean researchers have not made optimal use of available methodology. The survey revealed that a large proportion of studies did not use reliable sampling methods. Ad libitum sampling was used most often (59%). When anecdotal studies were excluded, 45% of 53 behavioral studies used ad libitum as the predominant method. Other sampling methods were continuous, onezero, incident, point, sequence, or scan sampling. Recommendations for sampling methods are made, depending on identifiability of animals, group sizes, dive durations, and change in group membership.
I studied behavior and range patterns of individual bottlenose dolphins during 1984 in the mid-eastern Gulf of California, Mexico. Dolphin sighting rate was significantly higher in areas close to estuary mouths, 0.306 sightings per hour compared with 0.155 sightings per hour in areas distant from estuary mouths. Dolphins used these estuarine areas to feed; 61% of all behavior observed near estuaries was feeding as compared with 23% elsewhere. Traveling comprised 61% of all behavior observed in areas distant from estuary mouths. Estuaries are sites of large concentrations of nutrients which support great numbers of filter-feeding zooplankton and fish. Bottlenose dolphins may specialize on esmarine prey, or they may feed in estuarine areas simply because of the abundance of potential prey that these systems support. In either case, data on relative numbers, distribution patterns, behavior and diet indicate that this is a general trend in habitat use for many coastal populations of this species in the Pacific and Atlantic.
Ranges of a few individuals spanned a minimum of 65 km of coastline, and animals were not permanent residents of a monitored bay. In contrast, dolphins off the coast of Sarasota, Florida, have been reported to be year-round residents with smaller ranges. This difference in degree of site fidelity may be related to habitat differences. The west coast of Florida is dotted with numerous and large estuarine systems which may host permanent prey populations and support resident groups of dolphins. The Gulf of California coastline contains few estuaries; most are small and perhaps support prey resources which are ephemeral, requiring dolphins to range over larger distances in search of food.
Recreational motorboats equipped with engines varying from 28 to 165 horsepower were operated at three selected Central Florida lakes. Also, a pair of isolation chambers representing aquatic habitats were placed in each lake for control and mixing studies. Mixing in isolation chambers was performed by small electrical motors connected to two blade propellers.Agitation of the water column in the lake mixing stations and inside the isolation chambers increased water turbidities and phosphorus concentrations. The increase in turbidity and phosphorus content occurred at a much higher rate than the rate of decline after cessation of mixing. The increase in phosphorus content could result in an increase in lake productivity as noticed from the increase of chlorophyll a concentrations in lake mixing stations.
We evaluated the impact of tourist visits on Asian rhinos Rhonoceros unicornis in Chitwan National Park, Nepal, by comparing the rhino's behavior during and after elephant-borne tourist visits to their behavior before visits. During the visits, the rhinos spent more time on alert and less time feeding. Close approaches (especially those under 10 m) were more disruptive, and frequently displaced the rhinos from the meadows where they preferred to feed. Visits were short (20·7 min average) and rhinos that were not driven out re-established their pre-visit pattern of behavior within 14 min of the tourists' departure. Moreover, these rhinos' home ranges overlapped extensively and individuals ranged widely so that each individual's encounters with tourists were usually several days apart. Eliminating close approaches would make these tourist visits relatively benign. However, this finding cannot necessarily be extended to other populations that might have different social systems.
Over the last decade there has been considerable growth in marine mammal-watching tourism throughout the world. Due to the species use of coastal habitats, bottlenose dolphins are most frequently exposed to dolphin-watching tourism. We conducted boat-based focal follows of schools of bottlenose dolphins to determine the effect of boats on dolphin behaviour. A CATMOD analysis showed that behaviour differed by boat number, in particular, resting behaviour decreased as boat number increased. Dolphins rested less and engaged in more milling behaviour in the presence of permitted dolphin-watching boats compared to non-permitted boats. An increase from 49 to 70 permitted trips per week and a change in their departure times resulted in a further decrease in resting behaviour. Currently the effects of boats, in particular permitted boats, on dolphin resting behaviour whilst they are in the Bay of Islands, are substantial. In the light of these findings we suggest that current legislation in New Zealand is not affording this isolated population protection from disturbance.
In this article we discuss our experience designing and implementing a statistical computing language. In developing this new language, we sought to combine what we felt were useful features from two existing computer languages. We feel that the new language provides advantages in the areas of portability, computational efficiency, memory management, and scoping.
Big brother is watching from under-water, above-water and on-land: assessing the behaviour of tour vessels around bottlenose dolphins. Abstract presented at the 14 th Biennial Conference on the Biology of Marine Mammals
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Victorian Coastal Strategy Draft
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