1,721,060 research outputs found
Cetacean-watching in developing countries: a case study from the Mekong River
No full text[Extract] Cetacean-watch tourism in developing countries remains poorly documented, and often poorly managed as a result of limited in-country capacity, ineffective governance, conflicting policy goals, and limited accountability. The dolphin-watch tourism that targets the population of Irrawaddy dolphins, Orcaella brevirostris, in the Mekong River in Cambodia and Laos is used as a case study to illustrate growing concerns associated with cetacean-watch tourism in developing countries. In the early 1990s, unregulated and unmanaged dolphin-watching tourism began in two of the most important habitats for this population, which now numbers less than 100 individuals. An Integrated Conservation Development Project, 'Dolphins for Development', was initiated in Kampi Village, Cambodia in 2004. This Project included an attempt to manage the existing dolphin-watch tourism through: (1) promoting the sharing of tourism revenue to the local community; (2) encouraging effective management of the industry to minimize threats to the dolphins; (3) promoting visitor satisfaction; and (4) raising community and visitor awareness of the status of the dolphins and the need for conservation. Although the initial results were encouraging, subsequent government intervention has resulted in: (1) a large increase in the number of boats operating in prime dolphin habitat and an increase in the harassment of dolphins; (2) reduction in the benefit to local communities; and (3) little or no information being provided to national or international tourists. Although management agencies are implementing significant conservation measures to reduce the threat to the dolphins from gillnet fishing by subsistence fishers, few efforts are being directed towards management of the dolphin-watch tourism industry. The urgent need to develop dolphin-watching tourism management initiatives in Cambodia was highlighted at the 2010 International Whaling Commission meeting, where a 'no vessel-based' dolphin tourism policy was recommended. A precautionary approach to management is needed to address the problem of unsustainable cetacean-watching currently occurring in numerous developing countries. This approach should be informed by location-specific and comprehensive studies on both the ecology of the dolphin-tourism interactions and the social, economic, managerial and political influences on cetacean-watch operations
Population dynamics and habitat use of bottlenose dolphins (Tursiops aduncus), Bunbury, Western Australia
Full text linkCoastal dolphins are increasingly exposed to a variety of human activities through the proliferation of coastal development. Threats to dolphins in near-shore environments include the loss of suitable habitat, increasing vessel traffic and tourism, entanglement in fishing gear or other marine debris, noise pollution, environmental contaminants and disease. Baseline data and long-term monitoring are needed to inform effective management initiatives to conserve dolphin populations. This study focused on the bottlenose dolphin (Tursiops aduncus) population that inhabits the waters around the rapidly developing city of Bunbury, Western Australia. This study investigated the spatial and temporal variability in population abundance, social dynamics, calving seasonality, home range size and habitat use of dolphins in Bunbury waters over a three-year study period. From 2007-2010, year-round boat-based, photo-identification surveys followed pre-determined transect lines within a 120 km2 study area (212 transect lines total; N=578 dolphin group encounters) to achieve intensive and consistent sampling effort. Abundance and demographic parameters were estimated using the capture-recapture Robust Design model. The model with Markovian temporary emigration was favoured over other varying parameters (survival, capture probability and emigration time). Abundance estimates varied from 65 individuals (± SE 8.53; 95% CI: 54- 90) in winter 2007 to 139 individuals (±SE 3.41; 95% CI: 134-148) in autumn 2009. The apparent adult survival estimate was 0.985 (±SE 0.006; 95% CI: 0.964- 0.994). Calving peaked in late February to early March. Associations between adult females showed an annual seasonal cyclic pattern that peaked during the breeding and calving season. Home range estimates were important in identifying critical habitat areas. Home range areas for individual dolphins were estimated using the Minimum Convex Polygon method and adult females occupied statistically different sized areas (ANOVA: P ≤0.0001). Females in sheltered inner waters (Leschenault Estuary and Koombana Bay) had smaller home ranges (7.4-24.6km2; N=9) than those in exposed coastal areas (home ranges: 32.1-125.2km2; N=9). Seasonal differences in ranging patterns were analysed using the kernel density hotspot method. During the summer and autumn calving season, there was a hotspot for adult females on the lee-side of an artificial groyne, adjacent to the Estuary and Bay. Habitat use was explored further through maximum entropy modelling. Reef habitat had the strongest influence over dolphin presence whilst distance from coast was a weak predictor. Managers can now focus on protecting this critical habitat. This project has demonstrated the benefits of intensive multi-year research on a population by detecting the seasonal differences in abundance, behaviour and habitat use – information critical to managing human impacts on this species. Future research should combine our spatial understanding of this dolphin population and human use of the area to conduct a risk assessment and rank the threats to these dolphins
Abundance and demographic parameters of spinner dolphins (Stenella longirostris subsp.) off Oʻahu's Waiʻanae Coast
Full text linkM.S
Integrating Emerging Technologies into Marine Megafauna Conservation Management
No full textThis eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contac
Patterns and Trends in Cetacean Occurrence Revealed by Shorewatch, a Land-Based Citizen Science Program in Scotland (United Kingdom)
Full text linkShorewatch is a citizen science project, managed by Whale and Dolphin Conservation (WDC), that records the occurrence of cetaceans during regular, standardized watches from a series of locations along the coast of Scotland (United Kingdom). Observer training and a clearly defined protocol help deliver a valuable source of information about cetacean occurrence and activity along the coast. Between 2005–2018, over 52000 watches generated over 11000 sightings of at least 18 cetacean species. Generalized Additive Models based on sightings for the five most commonly sighted species (bottlenose dolphin, harbor porpoise, minke whale, Risso’s dolphin, and common dolphin), at those sites with the longest time series, demonstrated seasonal, geographical and year-to-year differences in their local occurrence and relative abundance. Bottlenose dolphins are mainly present at observation sites located on the east coast of Scotland, being uncommon on the west coast, while harbor porpoise and minke whale are principally present at sites located on the west coast. The seasonality observed in cetacean occurrence is consistent with peak abundance in summer months described by previous studies in the area. Mean depth around the observation sites is the static variable that apparently has the greatest influence on species presence and number of sightings, except for Risso’s dolphin. All the species except bottlenose dolphin showed upward trends in occurrence and number of sightings over the period 2012–2018. Evidence of temporal autocorrelation was found between results from consecutive watches at the same site on the same day as well as between results from consecutive days at the same site. The power to detect declines in local abundance over a 6-year period depends on the underlying sighting rate of each cetacean species, the number of watches performed and the rate of decline. Simulations performed to determine the power to detect a decline suggest that the current intensity of observation effort in some observation sites, of about 2500 watches per year, may offer good prospects of detecting a 30% decline of the most frequently sighted species (95% of the time) over a 6-year period, although a more even distribution of observation effort in space and time is desirable. The data could potentially be used for monitoring and 6-yearly reporting of the status of cetacean populations
Investigating the Bottlenose Dolphins in the Swan Canning Riverpark using two research methods: A comparison between citizen science and professional science
Full text linkSince 2011 the Indo-Pacific bottlenose dolphin (Tursiops aduncus) community in the Swan Canning Riverpark in Perth, Western Australia has been studied simultaneously through a citizen science project (Dolphin Watch) and a professional science project (the Dolphin Population Assessment Project). The two projects share a common aim – to collect scientific information that supports the conservation of dolphins and their habitat – but use different methodologies.
This thesis examined how the two projects approach the study of a wildlife population and evaluated how citizen science and professional science projects can complement each other, leading to better outcomes than if one approach is applied in isolation.
Using the example of the Dolphin Watch and Dolphin Population Assessment Project; data over a one-year period was analysed. These projects ecological outcomes were assessed through: (1) quantity of sampling; (2) spatial and temporal distribution of dolphin sightings; and (3) dolphin group dynamics (group size/ sighting size). Additionally, the volunteer’s motivations and level of contribution was discussed in the context of Dolphin Watch. The main goal of this thesis was to investigate the extent of these projects’ ability to produce complementary ecological outcomes.
Firstly, Dolphin Watch collected a higher quantity of data than the Dolphin Population Assessment Project. Volunteers recorded a total of 2682.3 hours of sampling effort in contrast to the 64.2 hours recorded by professional scientists. Dolphin Watch volunteers recorded over 15 times more effort hours per zone than the professional scientists (Dolphin Watch = 81.28 hours/ zone; Dolphin Population Assessment Project = 5.35 hours/ zone). The higher quantity of data collected through Dolphin Watch was reflected throughout the study area and included the common monitoring zones (zones 20-31).
Data collected through Dolphin Watch was able to indicate the dolphin community in the Swan Canning Riverpark occupied all monitoring zones, which included approximately 58 kilometres of river ways. Dolphins were sighted in both the upstream Swan and Canning rivers and the downstream zones near Fremantle throughout the study period; this indicated that dolphins range throughout the Riverpark year-round. The Dolphin Population Assessment Project supported these findings by identifying the dolphin community exhibited characteristics of a resident population.
The two research projects recorded dolphin group dynamics in different ways that meant they were not directly comparable. The differences in data collection originate from the inability to uniformly identify dolphin group sizes using a specific criterion over multiple observers. Therefore, Dolphin Watch volunteers recorded the total number of dolphins within each sighting; whereas the Dolphin Population Assessment Project identified the group size based on the 100-metre chain rule.
Finally, this thesis identified examples of distinct differences between a citizen science and professional science project that studied the same dolphin community. This study supported the concept that ‘the type of research question asked will influence a project’s design’. Dolphin Watch and the Dolphin Population Project approached empirical research on the dolphin community differently; where their differences allowed them to complement each other and support each other’s claims
Integrating Emerging Technologies into Marine Megafauna Conservation Management
No full textThis eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contac
Hierarchical models and shrinkage estimators
Full text linkCapture-Mark-Recapture (CMR) models are a large class of hierarchical time-series models for estimating the abundance and survival of individually marked animals. Due to the complex multi-parameter nature of CMR models, CMR practitioners have been enthusiastic adopters of multi-model inference (MMI) techniques. By MMI, I refer loosely to a variety of techniques such as model-selection, model-averaging, Frequentist shrinkage estimators, and Hierarchical Bayesian random-e_ects. In this thesis, I develop and compare methods of MMI in CMR, with application to the movement and abundance of bottlenose dolphins, Tursiops sp., in Australia. I use novel ideas from the _eld of machine learning, as well as revisit old estimation problems like the Marginal Likelihood. As this thesis will show, there are many practical problems to the popular AIC/BIC-based methods in odontocetes CMR studies, such as singularities and boundary-value estimates. This is especially the case when there is a lot of demographic and/or temporal variation. Understanding such heterogeneity is important for conservation and ecological theory, such as the role of individual heterogeneity for estimating abundance (Chapter 3), or sex/age di_erences in movement patterns (Chapter 4). Such heterogeneity can also lead to severe non-identiability problems. I suggest practical solutions through HB models and shrinkage estimators. Chapter 2 reviews MMI theory and presents a new boosting algorithm for the Cormack-Jolly-Seber model. Chapter 3 presents a Hierarchical Bayesian (HB) version of Pollock's Closed Robust Design (PCRD), with emphasis on shrinkage priors and individual heterogeneity. Chapter 4 reviews Bayesian model selection and introduces a technique to estimate Marginal Likelihoods and Bayes Factors for hidden-Markov models, such as the PCRD. Chapter 5 generalizes the HB PCRD into a Multistate CRD model, with emphasis on shrinkage priors for inference on geographic state-transitions
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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