23 research outputs found
Distribution and habitat partitioning of cetaceans (Mammalia: Cetartiodactyla) in the Bohol Sea, Philippines.
Understanding broad-scale species distribution and finer-scale ecological interactions is essential for conservation. We assessed species richness, distribution, habitat use and interspecific associations of cetacean in the Bohol Sea, Philippines. During 72 days of dedicated survey (2010 - 2013), we encountered 12 species of cetacean in 291 sightings, 16.8% of which involved mixed species. We used maximum entropy (MaxEnt) models to assess species’ habitat suitability and found slope and distance from the coast to be influential contributors to cetacean distribution. To explore habitat use, through foraging ecology and niche segregation of sympatric species, we compared behavioral budgets across species and found significant differences (chi-sq = 21.44; p-value = 0.044). We then used GLMs to determine the foraging likelihood in relation to oceanographic features, group size and presence of associated species. Results from model selection complimented those derived from MaxEnt. However, some inter-specific exclusion behavior might also occur. Overall, our study suggests that the Bohol Sea supports a high cetacean biodiversity while more complex inter-specific dynamics might further shape species’ ecological niches. These results highlight the importance of multi-species ecology and can be used to develop management actions
Food-provisioning negatively affects calf survival and female reproductive success in bottlenose dolphins
Food-provisioning of wildlife can facilitate reliable up-close encounters desirable by tourists and, consequently, tour operators. Food-provisioning can alter the natural behavior of an animal, encouraging adverse behavior (e.g. begging for food handouts), and affect the reproductive success and the viability of a population. Studies linking food-provisioning to reproductive success are limited due to the lack of long-term datasets available, especially for long-lived species such as marine mammals. In Bunbury, Western Australia, a state-licensed food-provisioning program offers fish handouts to a limited number of free-ranging bottlenose dolphins (Tursiops aduncus). Coupled with long-term historical data, this small (<200 individuals), resident dolphin population has been extensively studied for over ten years, offering an opportunity to examine the effect of food-provisioning on the reproductive success of females (ntotal = 63; nprovisioned females = 8). Female reproductive success was estimated as the number of weaned calves produced per reproductive years and calf survival at year one and three years old was investigated. The mean reproductive success of provisioned and non-provisioned females was compared using Bayes factor. We also used generalized linear models (GLMs) to examine female reproductive success in relation to the occurrence of food-provisioning, begging behavior and location (within the study area). Furthermore, we examined the influence of these variables and birth order and climatic fluctuations (e.g. El Niño Southern Oscillation) on calf survival. Bayes factor analyses (Bayes factor = 6.12) and results from the best fitting GLMs showed that female reproductive success and calf survival were negatively influenced by food-provisioning. The negative effects of food-provisioning, although only affecting a small proportion of the adult females’ population (13.2%), are of concern, especially given previous work showing that this population is declining
Meta-analyses of whale-watching impact studies : Comparisons of cetacean responses to disturbance
Acknowledgements. The International Whaling Commission funded this study through a grant assigned to D.L. D.L. was also funded by the Scottish Funding Council for funding through grant HR09011 to the Marine Alliance for Science and Technology for Scotland. While writing the manuscript, V.S. was sponsored by a Fulbright scholarship. We thank the many people that replied to the 2 MAR - MAM calls and Dr. Stankowich for his previous comments on the manuscript.Peer reviewedPublisher PD
The value of Antarctic and Southern Ocean ecosystem services
Antarctica and the Southern Ocean provide numerous ecosystem services that benefit people globally, but many are ‘invisible’ to markets and to some decision makers. A subset of these services — Antarctic tourism, commercial fisheries, and a suite of inter-related regulating services — are conservatively valued at ~US $180 billion annually, highlighting their importance
The role of synchronized swimming as affiliative and anti-predatory behavior in long-finned pilot whales
Synchronized swimming in cetaceans has been hypothesized to play a role in affiliative processes as well as anti-predatory responses. We compared observed variation in synchronized swimming at two research sites in relation to disturbance exposure to test these two hypotheses. This study describes and quantifies pair synchronization in long-finned pilot whales at the Strait of Gibraltar, Spain and Cape Breton, Canada. Synchronization differed depending on the behavioral state and the response is different in the two sites leading to the conclusion that environment can shape the occurrence and magnitude of certain behaviors. We also analyzed intra-population variations in synchronization among 4 social units of Pilot whales in the Strait of Gibraltar and the results of this study confirmed the affiliative role of synchronization and highlighted an influence of disturbance on synchronization. We can conclude that synchronization is a common behavior in long-finned pilot whales that allow for close proximity and rapid coordinated response of individuals, with the multiple functions of showing affiliation and reacting to disturbance. © 2012 Elsevier B.V.Peer Reviewe
Author Correction: Food-provisioning negatively affects calf survival and female reproductive success in bottlenose dolphins
Correction to: Scientific Reports https://doi.org/10.1038/s41598-019-45395-6, published online 20 June 201
Close encounters of the dolphin kind: Contrasting tourist support for feeding based interactions with concern for dolphin welfare
The tourism demand for close interactions with wildlife has increased in the last few decades. At the same time, public concern for animal welfare has also increased. Tourists are drawn to the thrill of close encounters with charismatic wildlife in their natural setting which depend on the reliability of wildlife being in a certain place at a given time. Food provisioning is a form of operant conditioning that uses food rewards to attract wildlife, promoting spatially and temporally reliable wildlife encounters that satisfy the desire for close encounters with wildlife. However, a range of effects counter to wildlife welfare and conservation may result from both the provisioning and close encounters. Our study examines visitors' attitude and support towards regulated provisioning and identifies a gap between visitors' desire for close-up encounters, their concern for dolphin welfare and the documented negative impacts of close encounters and food-provisioning
The effect of submersion in different types of water on the survival and eclosion of blow-fly intra-puparial forms (Diptera: Calliphoridae)
Blow-fly (Diptera: Calliphoridae) immatures are the main colonizers of decomposing remains, and any information on what influences their growth and development are important to forensic entomologists when they are required to estimate post-mortem intervals during a death investigation. Much of this work has been qualified and quantified in terrestrial environments, but is deplete in aquatic environments. When considering a blow-fly's life history, the longest immature life stage goes from the formation of the puparium to adult emergence, and involves metamorphosis. In an aquatic scenario a corpse may be completely submerged, floating on the surface and or it could be associated with water but neither submerged or floating (e.g. beached on a seashore or washed up after a flood event). The present study concerns two blow-fly species, Lucilia sericata (Meigen) and Calliphora vomitoria (L.), and the effects of the age of the intra-puparial forms (“pupal age”) and resultant survival, when submerged in tap, river or salt water for varying times – up to 3 days. The experiment was conducted in two localities, L. sericata in Boston USA and C. vomitoria in Turin, Italy, and full puparia of both species were divided into 4 age cohorts (“white”, “young”, “medium”, and “old’) before submergence. L. sericata intra-puparial forms showed a three time greater survival rate compared to C. vomitoria intra-puparial forms when submerged in each of the three water types. Both species had the highest survival rate in tap water. Overall, younger and older intra-puparial forms showed a greater and significant survival rate than medium intra-puparial forms when submerged. The eclosion time following submersion of C. vomitoria and L. sericata was mainly influenced by both the age at which the intra-puparial forms were submerged, and by the type of water, but the duration of the submersion also influenced the eclosion time of L. sericata. These results are discussed considering blow-fly physiology. A deeper understanding of the dynamics of survival and growth rate of blow-fly intra-puparial forms on human remains that have undergone a period of submergence could assist in the estimation of the time of death in criminal cases connected to different aquatic environments
A global review of 50 years of polar tourism scholarship
The first peer-reviewed journal article on polar tourism was published in French by Canada-based Louis-Edmond Hamelin in 1974, marking 2024 as the 50th anniversary of polar tourism scholarship. This presentation discusses the results obtained from a meta-review of journal articles (n=626) searched in 22 different languages and tracks the development of polar tourism scholarship over time (1974-2022). The meta-review employed a keyword search of two online scholarly databases (Scopus and Google Scholar) and other regionally relevant searches. We identified four main phases of polar tourism scholarship. The early days of research (1974- 1991) represented an ‘exploratory’ phase, with an average number of less than one publication annually. This initial period was followed by an ‘establishment’ phase (1992–2006), during which the average number of publications per year increased to nine. A ‘development’ phase (2007-2016) followed, in which polar tourism scholarship grew substantially and solidified at about 19 publications annually on average. The final phase (starting in 2017), labelled the ‘integration’ phase, witnessed the average yearly number of publications to be generally more than twice that of those during the development phase and were dominated by multi-authored and multi-disciplinary scholarship. Also, this recent phase is the most linguistically diverse, with 10 publication languages represented, although articles in English continue to dominate the polar tourism literature (almost 75%). This is a finding not well-explored in previous meta-reviews, and it represents a growing scholarly interest across national boundaries and beyond those states typically associated with polar tourism. The incorporation of articles published in languages other than English allows us to present for the first time a comprehensive and global overview of scholarly output on polar tourism. This linguistic diversity is critical to understanding polar tourism as its growth intensifies and diversifies
Human food provisioning impacts the social environment, home range and fitness of a marine top predator
Food provisioning promotes close interaction with wildlife but can negatively impact the targeted species. Repeated behavioural disruptions have the potential to negatively impact vital rates and have population level consequences. In Bunbury, Western Australia, food-provisioned female bottlenose dolphins, Tursiops aduncus, suffer reduced reproductive success via lower calf survival. However, the proximal causes of this long-term negative effect remain unknown. To infer processes that could lead to fitness costs, we combined network analyses, Markov Chain, regression models and kernel density estimates to evaluate the social environment, behavioural budget and home range size of provisioned dolphins relative to their nonprovisioned counterparts. We found that provisioned dolphins spent significantly less time socializing and had smaller home ranges and weaker social associations than the nonprovisioned dolphins. Overall, these findings suggest that provisioned dolphins experience a more restricted social environment among themselves, which likely results from investing time in an unnatural foraging tactic around the provisioning site, in proximity to human activities. This modified social environment associated with food provisioning and begging behaviour, reinforced by the limited time spent socializing, could affect the opportunities of calves of provisioned females to acquire fitness-enhancing skills and form essential social bonds. This study highlights the need to consider the potential impact of human activities on the social environment of animals