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Van Bressem M.-F.,Cetacean Conservation Medicine Group CMED | Duignan P.J.,University of Calgary | Banyard A.,Animal and Plant Health Agency APHA | Barbieri M.,The Marine Mammal Center | And 31 more authors.
Viruses | Year: 2014

We review the molecular and epidemiological characteristics of cetacean morbillivirus (CeMV) and the diagnosis and pathogenesis of associated disease, with six different strains detected in cetaceans worldwide. CeMV has caused epidemics with high mortality in odontocetes in Europe, the USAand Australia. It represents a distinct species within the Morbillivirusgenus. Although most CeMV strains are phylogenetically closely related, recent data indicate that morbilliviruses recovered from Indo-Pacific bottlenose dolphins (Tursiops aduncus), from Western Australia, and a Guiana dolphin (Sotalia guianensis), from Brazil, are divergent. The signaling lymphocyte activation molecule (SLAM) cell receptor for CeMV has been characterized in cetaceans. It shares higher amino acid identity with the ruminant SLAM than with the receptors of carnivores or humans, reflecting the evolutionary history of these mammalian taxa. In Delphinidae, three amino acid substitutions may result in a higher affinity for the virus. Infection is diagnosed by histology, immunohistochemistry, virus isolation, RT-PCR, and serology. Classical CeMV-associated lesions include bronchointerstitial pneumonia, encephalitis, syncytia, and lymphoid depletion associated with immunosuppression. Cetaceans that survive the acute disease may develop fatal secondary infections and chronic encephalitis. Endemicallyinfected, gregarious odontocetes probably serve as reservoirs and vectors. Transmission likely occurs through the inhalation of aerosolized virus but mother to fetus transmission was also reported. © 2014 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license.

Zerbini A.N.,University of Washington | Zerbini A.N.,National Oceanic and Atmospheric Administration | Zerbini A.N.,Instituto Aqualie | Ward E.J.,University of Washington | And 4 more authors.
Journal of Cetacean Research and Management | Year: 2011

The population of humpback whales (Megaptera novaeangliae) wintering off the eastern coast of South America is referred to by the International Whaling Commission as 'Breeding Stock A' (BSA). This population was heavily exploited in 20 th century modern commercial whaling operations. After more than 30 years of protection, its present status remains unknown. A deterministic sex and age-aggregated population dynamics model was used to estimate the pre-exploitation population size (K), the maximum net recruitment rate (r max, the maximum depletion level (NJK), and other quantities of interest of BSA. Input data included modem whaling catch series, absolute estimates of abundance, observed growth rates and indices of relative abundance. A Bayesian statistical method was used to calculate probability distributions for the model parameters. Prior distributions were set on r - an uninformative (Uniform [0, 0.106]) and an informative (Normal [0.067,0.04 2]) - and on the population size in 2005 - N 2005 (Uniform [500,22,000]). A total of 10,000 samples were used to compute the joint posterior distribution of the model parameters using the Sampling-Importance-Resampling algorithm. Sensitivity of model outputs to the priors on r max, a genetic constraint, data inclusion and catch allocation scenarios was investigated. Medians of the posterior probability distributions of quantities of interest for the base case scenario were: r max = 0069 ( 95% probability intervals [PI] = 0.013-0.104), K = 24,558 (95% PI = 22,791-31,118), NJK = 2% (PI = 0.31%-12.5%), N 200d K = 27.4% (PI = 18.3%-39.5%), N 2020ZK = 61.8% (PI = 23.8%-88.6%), and N 204JK= 97.3% (PI = 31.6%-99.9%). Despite apparent recovery in the past three decades, the western South Atlantic humpback whale population is still low relative to its pre-exploitation size and requires continued conservation efforts.

Martins C.C.A.,University of Brasilia | Martins C.C.A.,Instituto Baleia Jubarte Humpback Whale Institute | Martins C.C.A.,University of Montréal | Andriolo A.,Federal University of Juiz de fora | And 3 more authors.
Ocean and Coastal Management | Year: 2013

One of the humpback whales' stocks uses the Brazilian Coast as breeding and calving ground during the austral winter. The species is recovering from commercial hunting and re-occupying previous breeding areas. Aerial surveys conducted to estimate the species density and abundance along the continental shelf of the Eastern Brazilian Coast revealed important core areas at the southern portion of the Abrolhos Bank. The rapid growth of human activities in these coastal areas motivated the use of Geographic Information Systems as a tool to guide the identification of priority areas for the species conservation. The species distribution was modelled using a kernel density estimator. The corresponding layer was used to identify areas of overlay with components of maritime traffic and with hydrocarbon exploitation areas. The resulting risk map was overlaid with existent Marine Protected Areas, allowing the cartography of areas where management measures still need to be undertaken to ensure habitat protection. These areas were identified as priorities for the species conservation as they encompass important breeding concentrations that were completely overlain by areas used to hydrocarbon exploitation and/or as navigation corridors. The present work gives support to an ecosystem-based management and ocean zoning of this portion of the Brazilian coast. © 2013 Elsevier Ltd.

Ward E.,University of Washington | Zerbini A.N.,University of Washington | Zerbini A.N.,Instituto Aqualie | Zerbini A.N.,National Oceanic and Atmospheric Administration | And 5 more authors.
Journal of Cetacean Research and Management | Year: 2011

Humpback whales wintering off the eastern coast of Brazil were heavily exploited by commercial whaling in the Southern Hemisphere. During recent years, clear signs of recovery have been observed, but few estimates of population growth rate exist. In this study, quantitative estimates of rates of population increase are obtained from sighting per unit of effort data (1995-98) using generalised linear models and maximum likelihood estimation. The error distributions considered for the models were Poisson and negative binomial. Predictors of the number of sightings included the year, month and 2-week periods during which the sightings were made. Predictors were treated as factors or numeric variables. For the numeric variables, quadratic dependence was also considered for each predictor to allow for possible non-linear relationships. Using Akaike Information Criterion (AICc) as a model selection criterion, the best model included year and month as continuous predictors. The data indicated strong support for the negative binomial over the Poisson models, but did not support models based on a finer temporal scale than month. Assuming year to be a linear predictor, the best estimate of the growth rate for the population wintering off Brazil was 7.4% per year (95% CI = 0.6-14.5%) during the period 1995-98. This estimate provides additional quantitative evidence that this population has been increasing and is consistent with the observed growth rates of other humpback whale stocks.

Ruegg K.,Stanford University | Rosenbaum H.C.,Wildlife Conservation Society | Rosenbaum H.C.,American Museum of Natural History | Anderson E.C.,Southwest Fisheries Science Center | And 5 more authors.
Conservation Genetics | Year: 2013

Once hunted to the brink of extinction, humpback whales (Megaptera novaeangliae) in the North Atlantic have recently been increasing in numbers. However, uncertain information on past abundance makes it difficult to assess the extent of the recovery in this species. While estimates of pre-exploitation abundance based upon catch data suggest the population might be approaching pre-whaling numbers, estimates based on mtDNA genetic diversity suggest they are still only a fraction of their past abundance levels. The difference between the two estimates could be accounted for by inaccuracies in the catch record, by uncertainties surrounding the genetic estimate, or by differences in the timescale to which the two estimates apply. Here we report an estimate of long-term population size based on nuclear gene diversity. We increase the reliability of our genetic estimate by increasing the number of loci, incorporating uncertainty in each parameter and increasing sampling across the geographic range. We report an estimate of long-term population size in the North Atlantic humpback of ~112,000 individuals (95 % CI 45,000-235,000). This value is 2-3 fold higher than estimates based upon catch data. This persistent difference between estimates parallels difficulties encountered by population models in explaining the historical crash of North Atlantic humpback whales. The remaining discrepancy between genetic and catch-record values, and the failure of population models, highlights a need for continued evaluation of whale population growth and shifts over time, and continued caution about changing the conservation status of this population. © 2012 Springer Science+Business Media Dordrecht.

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