Decline in Relative Abundance of Bottlenose Dolphins Exposed to Long‐Term Disturbance

Bejder, Lars; Samuels, Amy; Whitehead, Hal; Gales, Nick; Mann, Janet; Connor, Richard C.; Heithaus, Michael R.; Watson-Capps, Jana J.; Flaherty, Cindy; Krützen, Michael

doi:10.1111/j.1523-1739.2006.00540.x

Cited by 530 publications

(448 citation statements)

References 36 publications

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“…Recent studies have demonstrated that human‐generated sound can detrimentally affect animal hearing, communication, movements, and foraging (Shannon et al., 2015; Slabbekoorn et al., 2010). However, it is difficult to translate these effects into meaningful predictions about individual fitness and population‐level consequences, (Morley, Jones, & Radford, 2014) because animals could possibly move away from sound sources, the disturbance may be transient and the animals could compensate to prevent long‐term impacts (Bejder et al., 2006). Therefore, it is imperative there are more experimental studies performed on organisms that can be tracked to investigate directly whether common sources of human‐generated sound disrupt behavior and/or reduce survival (Simpson et al., 2016).…”

Section: Introductionmentioning

confidence: 99%

The effect of motorboat sound on Australian snapper Pagrus auratus inside and outside a marine reserve

Mensinger

Putland

Radford

2018

Ecology and Evolution

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Human‐generated sound affects hearing, movement, and communication in both aquatic and terrestrial animals, but direct natural underwater behavioral observations are lacking. Baited underwater video (BUV) were deployed in near shore waters adjacent to Goat Island in the Cape Rodney–Okakari Point Marine Reserve (protected) or outside the reserve approximately four km south in Mathesons Bay (open), New Zealand to determine the natural behavior of Australian snapper Pagrus auratus exposed to motorboat sound. BUVs worked effectively at bringing fish into video range to assess the effects of sound. The snapper inhabiting the protected area showed no behavioral response to motorboat transits; however, fish in the open zones either scattered from the video frame or decreased feeding activity during boat presence. Our study suggests that motorboat sound, a common source of anthropogenic activity in the marine environment can affect fish behavior differently depending on the status of their habitat (protected versus open).

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Section: Introductionmentioning

confidence: 99%

The effect of motorboat sound on Australian snapper Pagrus auratus inside and outside a marine reserve

Mensinger

Putland

Radford

2018

Ecology and Evolution

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“…Cetacean-based tourism is one of these growing potential threats and has resulted in increased exposure of dolphin and whale populations to high levels of boat traffic and disturbance (e.g. Bejder et al 2006b;Stensland and Berggren 2007;Stamation et al 2010).…”

Section: Introductionmentioning

confidence: 99%

“…Accordingly, management strategies can be modified depending on the habitat scale of the targeted animals, for example, resident versus non-resident populations, and/or the intensity of interactions with vessels (see e.g. Bejder et al 2006b;Stockin et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Distance does matter: close approaches by boats impede feeding and resting behaviour of Indo-Pacific bottlenose dolphins

2011

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Context. Potential impacts of human disturbance on animal populations can be measured as behavioural responses and may affect the survival and fecundity of animals. In areas where human-wildlife interactions occur, conservation management needs to be in place to secure both a viable tourism industry and the sustainability of the targeted species.Aims. We sought to evaluate whether different approach distances by boat have effects on the behaviour and group cohesion of dolphins that are targeted by Australia's largest dolphin-watching industry.Methods. The effects of different approach distances of boats on the behavioural states of dolphins, group dispersal and direction of movement were investigated in this area by controlled boat experiments conducted between August 2008 and December 2009.Key results. Results showed that there was significantly less feeding when boats approached dolphin groups to a distance of 50 m than when they did to a distance of 150 m, or with controlled approaches. Resting was also observed significantly less when boats approached to a distance of 50 m than when they approached to a distance of 150 m. The dispersal of dolphin groups was significantly tighter (less dispersed) when boats approached to 50 m than that with 150-m-distance or controlled approaches. Furthermore, the dolphins' direction of movement was less neutral when the experimental boat approaches were carried out at a distance of 50 m than when they were carried out at a distance of 150 m, or with controlled approaches. Similar results were also obtained for dolphin groups including calves.Conclusions. On the basis of the results from this study, we recommend that the existing New South Wales regulations, which stipulate that dolphin-watching boats keep a distance of 50 m to groups with adults only and 150 m to groups with calves, are maintained within the Port Stephens-Great Lakes Marine Park (PSGLMP).Implications. Management plans whose stated goals include both sustainability of a dolphin-watching industry and longer-term viability of a dolphin population may reconcile conflicting objectives and improve their decision making by using these empirical measures rather than best guesses.

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“…Short-term impacts associated with boat interactions include group directional changes (Steckenreuter, Möller, & Harcourt, 2012;, changes in group dispersion (Arcangeli & Crosti, 2009;Steckenreuter et al, 2012), heightened breathing synchrony (Hastie, Wilson, Tufft, & Thompson, 2003), increased dive times (Lusseau, 2003b) and changes in vocalizations (Buckstaff, 2004;Scarpaci, Bigger, Corkeron, & Nugegoda, 2000). Such changes can have longer lasting impacts resulting in seasonal (Rako et al, 2013) or long-term (Bejder et al, 2006) displacement and increased energy expenditure (Williams, Lusseau, & Hammond, 2006).…”

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confidence: 99%

Changes in bottlenose dolphin whistle parameters related to vessel presence, surface behaviour and group composition

et al. 2016

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Cetacean watching from tour boats has increased in recent years and has been promoted as an ethically viable alternative to cetacean viewing in captive facilities or directed take. However, short-and long-term impacts of this industry on the behaviour and energetic expenditure of cetaceans have been documented. Although multiple studies have investigated the acoustic 1 response of dolphins to marine tourism, there are several covariates that could also explain some of these results and should be considered simultaneously. Here, we investigated whether common bottlenose dolphins, Tursiops truncatus, inhabiting Walvis Bay, Namibia vary their whistle parameters in relation to boat presence, surface behaviour and/or group composition. We detected an upward shift of up to 1.99 kHz in several whistle frequency parameters when dolphins were in the presence of one or more tour boats and the research vessel. No changes were demonstrated in the frequency range, number of inflection points or duration of whistles. A similar, although less pronounced difference was observed in response to engine noise generated by the research vessel when idling, suggesting that noise alone plays an important role in driving this shift in whistle frequency. Additionally, a strong effect of surface behaviour was observed, with the greatest difference in whistle parameters detected between resting and other behavioural states that are associated with higher degrees of emotional arousal. Group composition also contributed to the variation observed, with the impact of boats dependent on whether calves were present or not. Overall these results demonstrate high natural variation in the frequency parameters of whistles utilized by dolphins over varying behavioural states and group composition. Anthropogenic impact in the form of marine tour boats can influence the vocalization parameters of dolphins and such changes could have a long-term impact if they reduce the communication range of whistles or increase energy expenditure. Key wordsbottlenose dolphin, marine tourism, Namibia, Tursiops truncatus, vocal behaviour Wildlife tourism involving cetacean (whale, dolphin and porpoise) watching has experienced rapid growth since the 1990s (Hoyt, 2001;O'Connor, Campbell, Cortez, & Knowles, 2009). 2Globally, boat-based cetacean watching generates an estimated 2.2 billion US dollars annually (IWC, 2014). Revenue can provide a valuable subsidy to fishing communities and in some cases wild cetacean viewing has replaced direct hunting of whales and dolphins (Amir & Jiddawi, 2001;Berggren et al., 2007). Compared with captive facilities, responsible boatbased cetacean watching has been promoted as an ethically acceptable option for observing dolphins, providing a valuable forum for environmental education and promotion of conservation efforts (IFAW, 1997). However, a considerable body of work has shown that boats and boat-based cetacean watching can have multiple negative impacts on the behaviour of the focal individual, population or species (Parsons,...

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Decline in Relative Abundance of Bottlenose Dolphins Exposed to Long‐Term Disturbance

Cited by 530 publications

References 36 publications

The effect of motorboat sound on Australian snapper Pagrus auratus inside and outside a marine reserve

The effect of motorboat sound on Australian snapper Pagrus auratus inside and outside a marine reserve

Distance does matter: close approaches by boats impede feeding and resting behaviour of Indo-Pacific bottlenose dolphins

Changes in bottlenose dolphin whistle parameters related to vessel presence, surface behaviour and group composition

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