Suchergebnisse

This study aimed to provide an insight on the ecology of the bottlenose dolphin population in Madeira archipelago. To achieve this, population structure; group dynamics, site-fidelity, residency and movement patterns within and out of the study area; survival and abundance estimates and spatial and temporal distribution and habitat preferences related to physiographic parameters using data collected between 2001-2011, were investigated. Photo-identification data analysis revealed strong evidences that bottlenose dolphins seen in the archipelago of Madeira belong to an open population with regular recruitment of new animals to the area. This population exhibited a typical fission-fusion society, in which short-term acquaintances prevail, with only a few long-lasting associations. Photo-identification methods demonstrated that there is a large variability in residency pattern, with resident, transient and migrant individuals. Only a small number of dolphins were found to be resident (4.3%). Social network diagram as well as SLAR analysis supported the existence of a mixed population of residents, migrants and transients. Mark-recapture methods estimated a high survival rate, within the range of other long-lived cetacean species. The resident community is composed of app. 180 individuals. In addition, around 400 dolphins of different residency patterns were found to use the south area of Madeira Island. Spatial distribution indicated that bottlenose dolphins were regularly found in shallow and closer to shore areas, suggesting the existence of biological processes influenced by bathymetry. Moreover, temporal patterns revealed no strong seasonal fluctuation in the presence of bottlenose dolphins in Madeira archipelago waters. Bottlenose dolphins are listed under the Annex II of the EU habitats Directive that requires the designation of Special Areas of Conservation (SACs) for this species; as such, the knowledge gained through this work can be used by governmental authorities to the establishment and management of areas for the conservation of bottlenose dolphin in Madeira archipelago.

AbstractPile driver‐generated noise has the potential to affect dolphin populations adversely as it is detectable up to 40 km from the source. At 9 kHz, this noise is capable of masking strong vocalisations within 10–15 km and weak vocalisations up to approximately 40 km. The masking radius reduces as the frequency increases: 6 km at 50 kHz and 1.2 km at 115 kHz. The impacts of masking are expected to be limited by the intermittent nature of pile driver noise, the dolphin's directional hearing, their ability to adjust vocalisation amplitude and frequency, and the structured content of their signals. Behavioural modifications have been observed in response to underwater sounds, including those produced by pile drivers, although in the latter case this may have been due to redistribution of prey species. A range of mitigation measures are proposed that are aimed at reducing the impact of pile driver noise on dolphin populations.

ACKNOWLEDGMENTS We would like to thank Bill Ruck, Moray First Marine and colleagues from the University of Aberdeen for assistance with the data collection. We are also grateful to Drs. Nathan Merchant and Adrian Farcas (CEFAS) for the provision of the data on the noise modeling and their valuable comments during the development of this work. The project benefited at all stages from input provided by the scientific steering groups and stakeholder groups established by UK and Scottish Governments to support the work conducted around these regional oil and gas and renewables projects. FUNDING Financial support for this study was provided through a series of consortia funded projects that involved the UK Department of Energy and Climate Change (DECC), Scottish Government, Oil and Gas UK Ltd., COWRIE, NatureScot, The Crown Estate, Highlands and Islands Enterprise, Beatrice Offshore Wind Ltd., and Moray Offshore Wind Farm (East) Ltd. OFB was funded by the Fundación "la Caixa" (Becas Posgrado, 2015) and their support was greatly appreciated. The authors declare that this study received funding from three commercial developers: Oil and Gas UK Ltd., Beatrice Offshore Wind Ltd., and Moray Offshore Wind Farm (East) Ltd. However, these funding bodies had no input into the study design, data collection, analysis, interpretation of data, the writing of this article or the decision to submit it for publication. ; Peer reviewed ; Publisher PDF

Bottlenose dolphins ( Tursiops truncatus and Tursiops aduncus; BND) live in coastal waters, prompting frequent contact with humans. Interaction with BND can be either planned (e.g. swim-with-dolphin experiences) or chance (e.g. BND surfing on boat wakes). These charismatic cetaceans are common in many forms of wildlife tourism, including marine wildlife tours, swim-with-dolphin experiences and hand feeding. BND also interact with humans by chance during ocean recreation activities, such as surfing, swimming and boating. Within fisheries, there is both cooperation and conflict between humans and BND. Through a literature review, this paper highlights the effects such interactions cause to both BND and humans with a focus on wildlife tourism, ocean recreation and fisheries.

Inshore bottlenose dolphins (Tursiops truncatus) show high levels of site fidelity that have enabled the establishment of dolphin watching activities worldwide. Bottlenose dolphins in Bocas del Toro, Panama live in a small and genetically isolated population. Dolphins, whose home ranges are primarily found within Dolphin Bay, are exposed to high levels of harassment by tour boats. Previous research shows that Dolphin Bay is a stressful environment for these dolphins. During encounters with tour boats, dolphin foraging and social activities are interrupted, mother-calf pairs are separated, and dolphins are sometimes injured by these interactions. As a result, the International Whaling Commission has repeatedly expressed concerns about the impacts of tourism activities on this dolphin population. This Honors thesis studies the group behavior, female reproduction, and calf survivorship of bottlenose dolphins in the archipelago of Bocas del Toro, Panama from 2004 to 2019. In my first chapter, I introduce this population. In chapter 2, I review the population characteristics of bottlenose dolphins in Bocas del Toro and compare them to other well-known populations that experience similar levels of harassment by tour boats. In chapter 3, I describe bottlenose dolphin group composition and behavioral activities in the context of calves from behavior data. Finally in chapter 4, I calculate female dolphin reproduction productivity and calf survivorship rates using photo-identification data (photos of natural marks on the dorsal fins of dolphins). My results show that groups with calves were larger in habitats where there is more tour-boat activity and when dolphins were engaged in social activities. Females in Bocas del Toro had a mean interbirth interval (IBI) of 54.96 months and a calf survivorship rate of 41.3%. Together, my results suggest a potential impact of tour-boat interactions, directly and indirectly, on the health of this dolphin population. The results will inform ongoing efforts by the government to protect these dolphins' critical habitat which will lead to stronger regulations on boat activity.

A captive Indo-Pacific bottlenose dolphin named &ldquo ; Jedol&rdquo ; was released from a zoo into the wild, in Jeju Island Sea off South Korea, in July 2013 to improve his welfare. Since he was illegally captured off the coast of Juju Island in May 2009, he had been performing in dolphin shows at Seoul Zoo, which is owned and operated by the Seoul Metropolitan Government. The release demanded considerable public expenditure, of which the source was local taxes gathered from the residents of Seoul. This paper seeks to conduct an ex-post evaluation of the release, employing the contingent valuation (CV) technique. A total of 500 households living in Seoul in 2013 participated in the CV survey to report their willingness to pay (WTP) for the release. Fifty-two percent were willing to accept an increase in local taxes over the next five years to carry out the release. The mean household WTP estimate was obtained as KRW 4880 (USD 4.56) per annum. The present values of the total WTP and the cost of the release are KRW 79.82 billion (USD 74.53 million) and KRW 751 million (USD 701,000), respectively, in 2013. Interestingly, the former is much more than the latter. We can conclude that the release was desirable from the point of view of Seoul residents.

M.N. was funded by a Crawford‐Hayes studentship and National Parks and Wildlife Service (NPWS), Department of Culture, Heritage and Gaeltacht, Ireland. E.D. was supported by the Beaufort Marine Research Award in Fish Population Genetics funded by the Irish Government under the Sea Change Programme. Financial support for A.D.F. was provided by the Welsh Government and Higher Education Funding Council for Wales through the Sêr Cymru National Research Network for Low Carbon, Energy and Environment, and from the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska‐Curie grant agreement No. 663830. ; The functioning of marine protected areas (MPAs) designated for marine megafauna has been criticized due to the high mobility and dispersal potential of these taxa. However, dispersal within a network of small MPAs can be beneficial as connectivity can result in increased effective population size, maintain genetic diversity, and increase robustness to ecological and environmental changes making populations less susceptible to stochastic genetic and demographic effects (i.e., Allee effect). Here, we use both genetic and photo-identification methods to quantify gene flow and demographic dispersal between MPAs of a highly mobile marine mammal, the bottlenose dolphin Tursiops truncatus. We identify three populations in the waters of western Ireland, two of which have largely nonoverlapping core coastal home ranges and are each strongly spatially associated with specific MPAs. We find high site fidelity of individuals within each of these two coastal populations to their respective MPA. We also find low levels of demographic dispersal between the populations, but it remains unclear whether any new gametes are exchanged between populations through these migrants (genetic dispersal). The population sampled in the Shannon Estuary has a low estimated effective population size and appears to be genetically isolated. The second coastal population, sampled outside of the Shannon, may be demographically and genetically connected to other coastal subpopulations around the coastal waters of the UK. We therefore recommend that the methods applied here should be used on a broader geographically sampled dataset to better assess this connectivity. ; Publisher PDF ; Peer reviewed

Context Animal species with overlapping ranges are common worldwide, but how these species coexist is less obvious. Dolphins are protected in Australia and yet little information is available on their resource use which is essential for successful management and conservation. Aim The aim of this study was to determine the degree of overlap in diet and feeding ecology of the two Tursiops spp. that have overlapping ranges in South Australia. Methods Stomach content (91 Tursiops sp. and 14 T. truncatus) and stable isotope (δ13C, δ15N) analyses (39 Tursiops sp. and 14 T. truncatus) were conducted. Carcasses of dolphins were opportunistically collected between 1974 and 2005. Diet was quantified by frequency of occurrence (FOO) and numerical abundance (NA) of prey. Key results Delta13C from teeth revealed distinct differences in primary source of carbon, corresponding to coastal (Tursiops sp. n = 39,  = –12.24, s.d. = 1.32) and offshore habitats (T. truncatus n = 14,  = –14.21, s.d. = 0.55). Differences in δ15N revealed Tursiops sp. ( = 11.66, s.d. = 0.58) feeds at a lower trophic level than T. truncatus ( = 14.29, s.d. = 0.88). Stomach content analyses for Tursiops sp. corroborated stable isotope results. There was a significant difference between the diets of Tursiops sp. from north Spencer Gulf and south Spencer Gulf (ANOSIM R = 0.249, P = 0.001). Prey were generally demersal in habit with the most important from the cephalopod families Octopodidae, Sepiidae and Loliginidae and fish families Carangidae, Clupeidae, Terapontidae and Apogonidae. For T. truncatus there were insufficient stomach contents for assessment. Conclusions South Australian bottlenose dolphin species exhibit distinct niche differentiation with clear evidence of regional variation in the diet of Tursiops sp. Implications The between and within species diet differentiation demonstrated, highlights the importance of regional management. Such results are internationally significant as coastal and offshore forms of Tursiops spp. occur worldwide.

This project was funded through the DECC Offshore Energy Strategic Environmental Assessment Programme using equipment previously purchased by DECC, Scottish Government, Oil and Gas UK, COWRIE and Moray Offshore Renewables Ltd. Scottish Natural Heritage, Beatrice Offshore Windfarm Ltd., MORL, Marine Scotland, The Crown Estate and Highlands and Islands Enterprise all provided funding for photo-identification surveys. Data have been made available in the Dryad repository at https://doi.org/10.5061/dryad.g3603. ; The development of risk assessments for the exposure of protected populations to noise from coastal construction is constrained by uncertainty over the nature and extent of marine mammal responses to man-made noise. Stakeholder concern often focuses on the potential for local displacement caused by impact piling, where piles are hammered into the seabed. To mitigate this threat, use of vibration piling, where piles are shaken into place with a vibratory hammer, is often encouraged due to presumed impact reduction. However, data on comparative responses of cetaceans to these different noise sources are lacking. We studied the responses of bottlenose dolphins and harbor porpoises to both impact and vibration pile driving noise during harbor construction works in northeast Scotland, using passive acoustic monitoring devices to record cetacean activity and noise recorders to measure and predict received noise levels. Local abundance and patterns of occurrence of bottlenose dolphins were also compared with a five-year baseline. The median peak-to-peak source level estimated for impact piling was 240 dB re 1 μPa (single-pulse sound exposure level [SEL] 198 dB re 1 μPa2 s), and the r.m.s. source level for vibration piling was 192 dB re 1 μPa. Predicted received broadband SEL values 812 m from the piling site were markedly lower due to high propagation loss: 133.4 dB re 1 μPa2 s (impact) and 128.9 dB re 1 μPa2 s (vibration). Bottlenose dolphins and harbor porpoises were not excluded from sites in the vicinity of impact piling or vibration piling; nevertheless, some small effects were detected. Bottlenose dolphins spent a reduced period of time in the vicinity of construction works during both impact and vibration piling. The probability of occurrence of both cetacean species was also slightly less during periods of vibration piling. This work provides developers and managers with the first evidence of the comparative effects of vibration and impact piling on small cetaceans, enabling more informed risk assessments, policy frameworks, and mitigation plans. In particular, our results emphasize the need for better understanding of noise levels and behavioral responses to vibration piling before recommending its use to mitigate impact piling. ; Publisher PDF ; Peer reviewed

ACKNOWLEDGMENTS This project was funded through the DECC Offshore Energy Strategic Environmental Assessment Programme using equipment previously purchased by DECC, Scottish Government, Oil and Gas UK, COW-RIE and Moray Offshore Renewables Ltd. Scottish Natural Heritage, Beatrice Offshore Windfarm Ltd., MORL, Marine Scotland, The Crown Estate and Highlands and Islands Enterprise all provided funding for photo-identification surveys. We thank Bill Ruck and col-leagues from University of Aberdeen and Moray First Marine for fieldwork support, and Global Energy, Cromarty Firth Port Authority, and other local stakeholders for information on the construction program. John Hartley, Francesca Marubini, and two anonymous reviewers kindly provided comments on the manuscript. ; Peer reviewed ; Publisher PDF

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.

ilustraciones ; Con autorización de uso ; The International Union for Conservation of Nature ? IUCN global conservation status for the bottlenose dolphins (Tursiops truncatus) is currently ?least concern?. However, in the Caribbean, small localized ?inshore form? populations of bottlenose dolphins may be in higher risk of extinction due to the combination of the relatively high population isolation, site fidelity, and strong anthropogenic pressures. Particularly, the population of dolphins in the Bocas del Toro Archipelago (Panama) shows high site fidelity, and it is characterized by high levels of dolphin-watching tourism activities happening in the area. Assessing inshore habits using both genetic and ecotoxicological data would provide needed information to change national conservation status and guarantee their conservation in the long-term. Following this, this Ph.D. thesis was developed with following aims 1) to establish population genetic structure and genetic diversity estimates of the bottlenose dolphins in Bocas del Toro in relation to the Caribbean; 2) to assess coastal habits of these dolphins using two ecological markers (stable isotopes and mercury concentrations); 3) to identify risk level for these dolphins to mercury exposition; 4) to discuss the relevance of using both genetic and ecotoxicological tools to delimit the bottlenose dolphin ecotypes; and 5) to compile and present all these scientific evidence to Panamanian government in order they implement an adequate management plan to protect this bottlenose dolphin population. Information presented in this work provides needed data to priories their national conservation, since isolation makes these animals vulnerable to several human activities, including exposition to mercury and not-regulated tour-boat traffic. It is recommended to the government of Panama that reevaluate the national conservation status of this bottlenose dolphin population, as preventive measure while a management plan is implemented in the Archipelago ; El estado de conservación global del delfín nariz de botella (Tursiops truncatus) por la Unión Internacional para la Conservación de la Naturaleza (UICN), es "preocupación menor". Sin embargo, en el Caribe, pequeñas poblaciones locales de delfines de la "forma inshore" podrían estar en riesgo de extinción debido a la combinación de aislamiento genético y alta filopatría. Particularmente la población de delfines que habita el Archipiélago de Bocas del Toro en Panamá muestra una alta residencia al sitio, y está expuesta a altos niveles de actividades turísticas relacionadas con el avistamiento turístico de delfines "dolphin-watching". La confirmación de los hábitos costeros de esta población de delfines usando tanto datos genéticos como ecotoxicológicos, puede proveer la información necesaria para cambiar su estado de conservación nacional de manera que se garantice su conservación a largo plazo. Bajo este contexto, se realizó esta tesis doctoral con los siguientes objetivos: 1) establecer la estructura genética poblacional y diversidad genética de la especie a nivel local respecto al Caribe; 2) determinar los hábitos costeros de esta población de delfines en el Archipiélago usando dos marcadores ecológicos (isótopos estables y concentraciones de mercurio); 3) identificar el grado de amenaza de los individuos ante la exposición a niveles de mercurio; 4) discutir la pertinencia del uso de herramientas genéticas y ecotoxicológicas para delimitar los ecotipos de delfín nariz de botella; y 5) recopilar y presentar esta información junto con evidencia previa al gobierno de Panamá como referente científico para implementar un plan de manejo adecuado que permita la conservación de esta población de delfines. La información presentada en este trabajo provee datos necesarios para priorizar su conservación en el país, ya que el grado de aislamiento de estos delfines los hace vulnerables a diversas actividades humanas, que incluyen la exposición a mercurio y al tráfico de botes ; Tesis Doctor en Ciencias - Biología ; Tesis Doctorado en Ciencias - Biología ; Doctorado