7 research outputs found
Individual variation in seasonal movements and foraging strategies of a land-locked, ice-breeding pinniped
Marine mammal satellite telemetry studies can provide important tests of movement and foraging theory. Here we present the first satellite tracking study of Caspian seals (Pusa caspica), an endangered, ice-breeding phocid seal, endemic to the Caspian Sea. The Caspian Sea is one of the most variable habitats inhabited by any pinniped species, and lacks competing large piscivores. Under such conditions foraging theory predicts individual variation in foraging strategy may develop to reduce intra-species competition. We deployed 75 Argos satellite tags 2009-2012 on adult seals of both sexes, and used State Space Modelling to describe movement, and behavioural states. During winter in all years most individuals were mobile within the icepack, making repeated trips into open water outside the ice field, with only brief stationary periods that may be related to breeding activity. During summer 2011, 60% of tagged animals migrated into the mid and southern Caspian, while the remainder spent the ice free season in the north. Summer foraging locations were not restricted by proximity to haul out sites, with animals spending more than 6 months at sea. Maximum dive depths exceeded 200m, and maximum duration was greater than 20 minutes, but 80% of dives were shallower than 15m and shorter than 5 minutes. Hierarchical cluster analysis identified 3 distinct groups of summer dive behaviour, comprising shallow, intermediate and deep divers, which were also spatially exclusive, suggesting potential niche partitioning and individual specialisation on prey or habitat types. The results can contribute to assessment of impacts from anthropogenic activities and to designation of protected areas encompassing critical habitats
VIRAL METAGENOMIC SURVEY OF CASPIAN SEALS
Viral diseases of pinnipeds cause substantial mortality and morbidity and can influence population demography. Viral metagenomic studies can therefore play an important role in pinniped health assessments and disease surveillance relevant to both individual species and in a 'One Health' context. This study used a metagenomic approach with high throughput sequencing to make the first assessment of viral diversity in Caspian seals (Pusa caspica), the only marine mammal species endemic to the Caspian Sea. Sequencing libraries from 35 seals sampled 2009-2020 were analysed, finding sequences from the viral families Circoviridae, Parvoviridae, Herpesviridae, Papillomaviridae, Picornaviridae, Caliciviridae, Cruciviridae, Anelloviridae, Smacoviridae, and Orthomyxoviridae, with additional detection of Adenoviridae via PCR. The similarity of viral contigs from Caspian seal to sequences recovered from other pinnipeds ranged from 63.74% (San Miguel sea lion calicivirus) to 78.79% (Seal anellovirus 4). Some may represent novel viral species, but overall, the viral repertoire of Caspian seals is similar to available viromes from other pinnipeds. Among the sequences recovered were partial contigs for influenza B, representing only the second such molecular identification in marine mammals. This work provides a foundation for further studies of viral communities in Caspian seals, the diversity of viromes in pinnipeds more generally, and contributes data relevant for disease risk assessments in marine mammals
Methods of Freeze Protection for Fruit Trees by Means of Renewable Energy Sources
As the Earth climate changes, the current horticulture gives rise to an acute issue - protecting fruit trees from spring frosts and their root system from freezing in severe winters with little snow. The authors substantiated the methods of how to protect fruit trees from frost and their root system from freezing, as well as a method of how to control their phenological phases based on the study of the heatmass- exchange intensification in a certain soil area occupied by the root system of a tree with various engineering aids to be designed. The aforesaid method is based on the operation of a heat and cold separator, which makes it possible to intensify heat transfer and expand the area of specific heat loads removed using a coolant - potassium salt brine (aqueous 30% KCL solution). The test results have shown that the coolant heated by the heat of the soil to a temperature of 12°С, gradually moving up at a depth of 0.9 m, heats the soil to 7°С at a depth of 0.5 m and up to 1°С on the surface of the earth at an ambient temperature of up to - 10°С. The heat of the lower soil layers comes up to the surface; in the soil area occupied by the root system, the temperature is redistributed, stabilized in a state that excludes freezing of the root system of the fruit tree. A rational value of the effective head has been determined to be equal to 2200 Н/m2 at the depth of the heated soil surface up to 1 m, with a specific heat flow of about 4•105 W/m2. In addition, a rational flow rate of the coolant is set equal to (1.5 ... 2.5) Gmin to produce more optimal heat transfer and additional body force of the heat and cold separator. The method of controlling the phenological phases of fruit trees by heating or cooling a certain soil area occupied by the root system is possible using an installation that generates power from the renewable resources (solar energy, wind or biogas plant), depending on climatic conditions and terrain
Exposure of wild Caspian seals (Pusa caspica) to parasites, bacterial and viral pathogens, evaluated via molecular and serological assays
Disease surveillance of marine mammal populations is essential to understand the causes of strandings, identify potential threats to animal health, and to support development of conservation strategies. Here we report the first large multi-pathogen screening of prevalence for viruses, bacteria and parasites in a sample of 177 live, healthy, wild Caspian seals (Pusa caspica), captured and released during satellite telemetry studies 2007-2017. Employing molecular and serological assays we assess prevalence of pathogens known to be of significance for marine mammal health worldwide, and evaluate the results in relation to Caspian seal health and conservation. RT-PCR, and PCR assays find evidence for infection by Canine Distemper Virus (CDV), Phocine herpes virus, phocine adenovirus and Influenza A at prevalences of 5%, 6.4%, 21.7%, and 4% respectively. The genomes of CDV isolates collected in 2008 showed 99.59% identity with the 2000 Caspian seal CDV epizootic strain. A partial coding sequence for the Us2 gene from the Caspian seal herpes virus was identical to PhHV-1 isolate PB84, previously reported from a harbor seal (Phoca vitulina), while amplicon sequences for the adenovirus polymerase gene indicated a novel strain. ELISA assays detected exposure to Influenza A (55% of tested samples), adenovirus (25%), coronavirus (6%), CDV (8%), herpes virus (94%), Toxoplasma gondii (2.6%) and heartworm (1%). Hemagglutination inhibition (HI) tests detected exposure to Influenza B at a prevalence of 20%, and Leptospira microscopic agglutination tests detected suspected exposure to Leptospira serovars in 9% of tested samples. Overall, the risks, profile and prevalence of pathogens in Caspian seals appear comparable to other wild phocid seal populations. Our results suggest Caspian seals have exposure pathways to pathogens with epizootic potential or ability to cause significant morbidity, and disease impacts could reduce the resilience of the population to other conservation threats. Caspian seals are listed as Endangered by the International Union for Conservation of Nature, and we recommend that resources are invested to support further surveillance programmes and to understand how anthropogenic pressures may influence future disease risks