146 research outputs found

    Inferring surface time of Minke whales from inter-surfacing interval data using a hidden Markov model

    Get PDF
    Surfacing rate data of Minke whales is an important factor used in the abundance estimates of Minke whale (Balaenoptera acutorostrata) stocks, both in aerial and vessel based surveys. Today, most abundance estimates of Minke whales rely on VHF-transmitters data rather than visual data. Visual data collected from land has the advantage of being relatively cheap to collect, which allows data to be collected from a larger number of individuals while causing no effect on the surfacing rates of the animals being studied, hence limiting biases. In this study, individual follows of Minke whales were conducted from a land-based station in FaxaflĂłi bay, Iceland, and data on inter-breath intervals (IBI) were collected. Two distinct dive types were present within the surfacing data, which we defined as regular dives and deep dives. Those emerged from two different biological processes: whales spending time at the surface and whales engaging in foraging activities. A hidden Markov model was used to identify and define the density distribution of IBI as the observation state of these two hidden diving processes. Regular dives had a mean surfacing interval of 43 seconds (SD=44.8) and deep dives had a mean surfacing interval of 155 seconds (SD=115.1). The transition probabilities between the two dive types were estimated, from which the relative proportion spent in each dive type could be inferred. Minke whales perform regular dives during 62% and deep dives during 38% of their time. The relative proportions spent in each dive type can be used as estimates of how much time a whale will be typically at the surface available to be detected during cue counting surveys and to estimate the odds that a whale is in a long dive and therefore unlikely to be detected. Data was also collected from commercial whalewatching boats in the same bay, and were analysed together with the land based data to measure the effect of whalewatching boat interaction on Minke whale surface intervals. The proportion of time spent in deep dives decreased from 38% to 14% during interactions with whalewatching boats, while regular dives increased from 62% to 86%. The inter-surfacing interval used in abundance estimates of Minke whales in the North Atlantic today is derived from VHF-transmitter data and is about 77 seconds. Our mean values of surface intervals lies below and above this mean, which raises the question if a single mean value of surfacing interval can be used to make reliable abundance estimates of Minke whales, as both the dive type and the presence of vessels is likely to affect this value

    Structure and Dynamics of Minke Whale Surfacing Patterns in the Gulf of St. Lawrence, Canada

    Get PDF
    Funding: This work was supported by the Foundation for Marine Environment Research (ORES), Switzerland and Ocean Care, Switzerland. Copyright: © 2015 Christiansen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedPeer reviewedPublisher PD

    Sensitization to Skin-associated Microorganisms in Adult Patients with Atopic Dermatitis is of Importance for Disease Severity.

    Get PDF
    Atopic dermatitis (AD) is a chronic inflammatory skin disease. Environmental and genetic factors, as well as microbial products from yeasts and bacteria, play a role in triggering the disease. A cohort of 619 adult patients with AD was screened for severity of AD, sensitization to Malassezia sympodialis, Candida albicans, Staphylococcus aureus enterotoxins and Dermatophagoides pteronyssinus. Serum levels of interleukin (IL)-18 were measured. Immunoglobulin E (IgE) sensitization to the combination of both yeast and mite antigens was found to be associated with more severe disease and higher levels of total IgE. AD patients with IgE sensitization to several microbial antigens had more severe disease than those with no IgE sensitization to microbial antigens. Sera from patients with IgE-associated AD showed higher levels of IL-18. Skin-associated microorganisms are exogenous factors triggering IgE-response and severity of AD. These findings are clinically important, and sensitization to these organisms should be assessed and considered in treatment strategies

    Effects of tourist boats on the behaviour of Indo-Pacific bottlenose dolphins off the south coast of Zanzibar

    Get PDF
    The short-term effects of tourist boats on the behaviour of Indo-Pacific bottlenose dolphins Tursiops aduncus were investigated off the south coast of Zanzibar, Tanzania, by comparing dolphin group behaviour in the presence (impact) and absence (control) of tourist boats. Groupfollows were conducted from a carefully maneuvered (non-invasive) independent research vessel and behavioural data on group activity were collected using scan sampling methods. By using a timediscrete Markov chain model, the transition probabilities of passing/changing from one behavioural state to another were calculated and compared between impact and control situations. The data were further used to construct behavioural budgets. In the presence of tourist boats, dolphins were less likely to stay in a resting or socialising activity but were more likely to start travelling or foraging, as inferred from the Markov chain model. The behavioral budgets showed that foraging, resting and socialising all decreased as an effect of tourist boat presence, while travelling increased. The behavioural responses are likely to have energetic implications, mainly by increasing physical demands. Further, the results demonstrate that the current level of tourism intensity off the south coast of Zanzibar affects the dolphins' cumulative behavioural budget. Regulations on dolphin tourism are therefore urgently needed to minimise potential long-term negative effects on the dolphins

    FrÄn förening till företag - Sportslig kontra ekonomisk framgÄng

    Get PDF
    Syftet med uppsatsen Àr att undersöka vad framgÄng Àr i dagens skandinaviska elitfotbollsklubbar och vilka strategier som Àr anvÀndbara för att uppnÄ denna. Uppsatsen Àmnar sÄledes belysa och klargöra de viktigaste aspekterna i en lyckad strategi inom en modern skandinavisk fotbollsklubb. Med denna kunskap har vi för avsikt att Äterge en bild över hur en elitfotbollsklubb strategiskt bör organiseras och ledas för att nÄ framgÄng. PrimÀrdata har insamlats genom kvalitativa semi-strukturerade intervjuer med FC Köpenhamn, Malmö FF och genom telefonintervjuer med IF Elfsborg. SekundÀrdata har frÀmst baserats pÄ vetenskapliga artiklar, rapporter och teoretisk litteratur. Vi har baserat vÄrt teoretiska perspektiv utifrÄn teorier inom Sport management, Komplexitetsteorin samt The crisis curve. Vi har kommit fram till att professionella fotbollsklubbar först mÄste bygga en stabil organisatorisk grund för att sedan kunna nÄ sportsliga framgÄngar

    Disentangling the cause of a catastrophic population decline in a large marine mammal

    Get PDF
    Considerable uncertainties often surround the causes of long-term changes in population abundance. One striking example is the precipitous decline of southern sea lions (SSL; Otaria flavescens) at the Falkland Islands, from 80 555 pups in the mid 1930s to just 5506 pups in 1965. Despite an increase in SSL abundance over the past two decades, the population has not recovered, with the number of pups born in 2014 (minimum 4443 pups) less than 6% of the 1930s estimate. The order-of-magnitude decline is primarily attributed to commercial sealing in Argentina. Here, we test this established paradigm and alternative hypotheses by assessing (1) commercial sealing at the Falkland Islands, (2) winter migration of SSL from the Falkland Islands to Argentina, (3) whether the number of SSL in Argentina could have sustained the reported level of exploitation, and (4) environmental change. The most parsimonious hypothesis explaining the SSL population decline was environmental change. Specifically, analysis of 160 years of winter sea surface temperatures revealed marked changes, including a period of warming between 1930 and 1950 that was consistent with the period of SSL decline. Sea surface temperature changes likely influenced the distribution or availability of SSL prey and impacted its population dynamics. We suggest that historical harvesting may not always be the “smoking gun” as is often purported. Rather, our conclusions support the growing evidence for bottom-up forcing on the abundance of species at lower trophic levels (e.g., plankton and fish) and resulting impacts on higher trophic levels across a broad range of ecosystems

    Food provisioning increases the risk of injury in a long-lived marine top predator

    Get PDF
    Funding This publication was supported by the US Department of Commerce's National Oceanic and Atmospheric Administration under NOAA Award NA14OAR4170098, the Mississippi-Alabama Sea Grant Consortium (Project R/MG/BR-15B). Long-term data were collected with additional major support from the Batchelor Foundation, Disney's Worldwide Conservation Fund, Dolphin Quest, Earthwatch Institute and the Chicago Zoological Society. The views expressed herein do not necessarily reflect the views of any of those organizations.Peer reviewedPublisher PD

    Estimating body mass of sperm whales from aerial photographs

    Get PDF
    We wish to thank FundaciĂłn Biodiversidad for supporting COLCA project and all the ecovolunteers involved in the fieldwork of the Balearic Sperm Whale project. We are grateful to OceanCare (Switzerland) for their continuous support of the sperm whale research and conservation activities of the PCRI since 2008 and to Prof. Kostas Kostarelos and the University of Manchester for organizing the crowd-funding project “Nanowhales” to cofund the research expedition of 2019 along the Hellenic Trench. This paper represents HIMB and SOEST contribution nos. 1903 and 11568, respectively.Body mass is a fundamental feature of animal physiology. Although sperm whales (Physeter macrocephalus) are the largest toothed predators on earth, body mass is seldom included in studies of their ecophysiology and bioenergetics due to the inherent difficulties of obtaining direct measurements. We used UAV‐photogrammetry to estimate the weight of free‐ranging sperm whales. Aerial photographs (23 calves, 11 juveniles, 55 nonmother adults, 13 mothers) were collected in the Eastern Caribbean and Mediterranean Sea during 2017–2020. Body length, widths, and heights (dorso‐ventral distance at 5% increments) were measured from dorsal and lateral photographs, while body volume was calculated using an elliptical model. Volume varied noticeably (12.01 ± 4.79 m3) in larger animals (>8 m), indicating fluctuations in body condition of adults and mothers. Volume was converted to mass, using tissue‐density estimates from catch data, animal‐borne tags, and body‐tissue composition. Average total body density ranged from 834 to 1,003 kg/m3, while the weight predictions matched with existing measurements and weight‐length relationships. Our body‐mass models can be used to study sperm whale bioenergetics, including inter‐ and intraseasonal variations in body condition, somatic growth, metabolic rates, and cost of reproduction.Publisher PDFPeer reviewe

    Decadal decline in maternal body condition of a Southern Ocean capital breeder

    Get PDF
    DATA AVAILABILITY : The data that support the findings of this study are available from the corresponding author upon reasonable request.The changing physical properties of the Southern Ocean are known to impact the recruitment and survival of Antarctic krill (Euphausia superba). For oceanic krill predators, the resulting reduced energy intake may lead to population-level effects likely preceded by an alteration in the animals’ body condition. This is especially true for capital breeders that rely on stored energy for successful reproduction. One such Southern Ocean capital breeder, the southern right whale (Eubalaena australis), has been monitored over the past 43 years in their South African wintering ground. Changes in the population have been documented in the past decade, including a decreased reproductive rate and a shift in foraging strategy. To evaluate if a reduced foraging success is an underlying factor, we assessed the temporal variation in morphological body condition through aerial photogrammetry. Results showed a 23% reduction in maternal body condition, potentially contributing to the decreased reproductive rate of the population. To the best of our knowledge, this is the first study to quantify a decadal reduction in the body condition of a capital breeder dependent on Southern Ocean productivity. Understanding the bioenergetic consequences of environmental change is vital to predicting species’ resilience to climate change.ExxonMobil, ENI, Anadarko and Total Energies, and the National Research Foundation (NRF), South Africa.https://www.nature.com/srepam2024Mammal Research InstituteSDG-14:Life below wate
    • 

    corecore