Toxoplasma gondii, a zoonotic parasite of global importance, infects all endothermic vertebrates, with extensive health implications. The prevalence of this parasite is seldom monitored in wildlife. ...Here, a semi-aquatic species, the Eurasian otter (Lutra lutra) was used as a model to assess the potential effect of climate, land cover and biotic factors on T. gondii seroprevalence in British wildlife. The Sabin-Feldman cytoplasm-modifying dye test identified T. gondii antibodies in 25·5% of blood samples from otters found dead, mainly as road kill, in England and Wales, between 2004 and 2010. Otters in the east of England were more likely to be infected with T. gondii than those in western regions. Land cover and temperature are key determinants of T. gondii infection risk, with more infection in arable areas and lower infection where temperatures are higher. The probability of T. gondii infection increased with host age, reflecting cumulative exposure with time, but there was no association between T. gondii seroprevalence and cause of host death.
Lack of data on population sizes and resource requirements are major impediments to the effective conservation of rare species globally. The conservation of the Eurasian otter (Lutra lutra) in Hong ...Kong reflects many of these key challenges for elusive and difficult‐to‐study mammals. It is a rare carnivore that has narrowly escaped extirpation, now surviving within a human‐dominated environment. Using sign surveys and spraint analysis, we recorded only 40 fresh spraints from 246 otter signs locations, over 4 months of intensive sampling across 2 years. Records were restricted to the Mai Po wetlands, confirming this as the core area for Hong Kong's otter population. Molecular analysis and microsatellite genotyping identified a minimum of seven individuals, two pairs of which were likely related. The genetic and sign data together strongly indicate a small population. Fish dominated the otter diet, highlighting the importance of fishpond habitats as a premium foraging resource. Given the rapid changes surrounding the Mai Po area (especially the new Northern Metropolis Development Strategy), maintaining quality and connected habitats, in addition to sustaining commercial fishponds will be key to otter recovery and long‐term population viability in Hong Kong.
Eurasian otter (Lutra lutra) are declining widely across China and remain rare and virtually unstudied in Hong Kong. We intensively sampled spraints in the Mai Po wetlands across two years and through microsatellite genotyping identified seven individuals and a dominance of fish (97%) in their diet based on prey‐remains analysis. Our results emphasize the small size of the otter population and their reliance on fishponds in the landscape.
•Neotropical otter reproductive season lasts six months, from October to March.•Proportion of estradiol and testosterone metabolites allow sex-id of wild otter feces.•Sex-id of feces was possible ...only during the reproductive season.•This tool can be used in determination of sex structure of wild populations.
Before there was use of ultrasonographic imaging, determination of the ratio of estrogens to androgens in the same individual was a technique used for differentiating the sex of monomorphic animals in captivity, with larger estrogen concentrations in the females. Due to species-specific differences in both concentration and changes throughout the year of these hormones, corroboration of the method is needed in each case. In this study, there was use of a chemo-immuno assay to quantify sex steroids in fecal samples collected from seven (five females and two males) Neotropical otters, Lontra longicaudis. The reproductive season for this species was determined to be between October and March, with increased estradiol in the females and relatively greater concentrations of testosterone in the males as compared with other seasons of the year. Results from utilization of a k-means analysis procedure indicated that the use of steroid ratios in fecal samples to differentiate otter sex is an effective technique when there are evaluations during the breeding season. The estrogen to androgen ratios during this period, however, are the inverse of what was expected, with there being larger testosterone concentrations in the female otters. The ratio of estrogens to androgens in feces of captive otters can be effectively used to determine the sex of otters in the field. We propose this method is reliable for sex determination in wild otter populations during the reproductive season.
Osteoporosis is a skeletal disease that occurs in many mammals. Our report describes osteoporosis in an Asian small-clawed otter (Aonyx cinereus). Gross, histological, and radiographic observations ...showed that all of the bones had numerous pockmarks on their surfaces. Histologically, the pockmarks were filled with fibrous tissue without inflammation. However, the spongy bone was normal according to the histological and radiographic results. Overall, the results showed that this was a case of osteoporosis that mainly involved external rather than internal surfaces.
Southern sea otters (Enhydra lutris nereis) are a federally listed threatened keystone species of the California kelp forest ecosystem and a sentinel species, indicating environmental health. Mercury ...(Hg) is a bioaccumulative neurotoxin that poses a threat to high trophic‐level species such as marine mammals. We quantified total Hg (THg) concentrations in fur, brain, and liver tissues of necropsied southern sea otters (n = 44) that stranded along the California coast from 2010 to 2019. THg concentrations differed significantly between fur and brain, and between liver and brain. Tissue type explained 64%, and sex explained only 3.3% of overall THg variability (0.48–46.1 μg/g dry weight). All individuals had liver Hg concentrations measuring well under the proposed lower‐limit low risk guideline for harp seals, Pagophilus groenlandicus. However, six sea otters exceeded the liver THg moderate risk threshold for terrestrial furbearers to which sea otters are closely related. These data represent baseline THg concentrations in fur, brain, and liver of the southern sea otter and build upon previous studies in various sea otter subspecies. Research on sea otter Hg tolerance and continued monitoring are needed to clarify potential health risks associated with the tissue concentrations observed in this study.
Dirgantara AP, Megantara EN, Husodo T, Febrianto P, Wulandari I, Shanida SS. 2021. The existence of Asian small-clawed otter (Aonyx cinereus Illiger, 1815) in the UCPS Hydropower, Cianjur, West Java. ...Biodiversitas 22: 4391-4401. Little information about the existence of small-clawed otters (Aonyx cinereus) in Indonesia is available. Small-clawed otter is the top predator and biological indicator of wetland health. However, the small-clawed otter population in the world has decreased due to anthropogenic factors. This study aims to reveal 1) estimate the population size of small-clawed otters and 2) the small-clawed otter signs at the UCPS Hydropower construction site, Cianjur, West Java. This study used a qualitative approach in February-April 2017. Sign surveys (feces, footprints, leftovers, and dens) and camera trapping were applied in this study. There were 32 signs with details of 21 feces, eight footprints, and three dens. The estimation of small-clawed otter population size at UCPS Hydropower ranges from 5-14 individuals in total scattered in the Citali-Cisokan, Cilengkong, and Cirumamis rivers. In addition, the discovery of infant and bedding repair activities shows that the habitat in the UCPS Hydropower area supports the daily needs of small-clawed otters, especially in terms of breeding and shelter. Further studies are needed regarding the impact of the UCPS Hydropower construction on the existence of small-clawed otters, especially in the overlapping between small-clawed otter habitat and the UCPS Hydropower construction sites, by monitoring and making wildlife management policies.
For more than ten thousand years, Native Americans from Alaska to southern California relied on aquatic animals such as seals, sea lions, and sea otters for food and raw materials. Archaeological ...research on the interactions between people and these marine mammals has made great advances recently and provides a unique lens for understanding the human and ecological past. Archaeological research is also emerging as a crucial source of information on contemporary environmental issues as we improve our understanding of the ancient abundance, ecology, and natural history of these species. This groundbreaking interdisciplinary volume brings together archaeologists, biologists, and other scientists to consider how archaeology can inform the conservation and management of pinnipeds and other marine mammals along the Pacific Coast.
Detailed postmortem examination of southern sea otters (Enhydra lutris nereis) found along the California (USA) coast has provided an exceptional opportunity to understand factors influencing ...survival in this threatened marine mammal species. In order to evaluate recent trends in causes of mortality, the demographic and geographic distribution of causes of death in freshly deceased beachcast sea otters necropsied from 1998–2001 were evaluated. Protozoal encephalitis, acanthocephalan-related disease, shark attack, and cardiac disease were identified as common causes of death in sea otters examined. While infection with acanthocephalan parasites was more likely to cause death in juvenile otters, Toxoplasma gondii encephalitis, shark attack, and cardiac disease were more common in prime-aged adult otters. Cardiac disease is a newly recognized cause of mortality in sea otters and T. gondii encephalitis was significantly associated with this condition. Otters with fatal shark bites were over three times more likely to have pre-existing T. gondii encephalitis suggesting that shark attack, which is a long-recognized source of mortality in otters, may be coupled with a recently recognized disease in otters. Spatial clusters of cause-specific mortality were detected for T. gondii encephalitis (in Estero Bay), acanthocephalan peritonitis (in southern Monterey Bay), and shark attack (from Santa Cruz to Point Año Nuevo). Diseases caused by parasites, bacteria, or fungi and diseases without a specified etiology were the primary cause of death in 63.8% of otters examined. Parasitic disease alone caused death in 38.1% of otters examined. This pattern of mortality, observed predominantly in juvenile and prime-aged adult southern sea otters, has negative implications for the overall health and recovery of this population.
Le chalut à panneaux, principal engin de pêche de fond commercial du 20e siècle, a vu le jour vers 1860 comme matériel de pêche récréative, probablement par la fusion de panneaux de chalut de surface ...(« otter boards») et de chaluts irlandais (« hammer trawls »). Il était utilisé par lesplaisanciers et les scientifiques, mais son acceptation par les pêcheurs commerciaux a dû attendre l'arrivée du chalutage à vapeur à partir de 1881, l'installation de panneaux de chalut sur les filets carrés des chaluts àperche vers 1890 et la promotion de cette combinaison auprès des funes enpair à partir de 1894. L'adoption du nouvel engin se fit alors très rapidement. Par contre, l'évolution du chalutage à panneaux vers un système efficace de récolte du poisson de fond s'est prolongée jusqu'aux années 1920. Parmi les avances nécessaires, notons les treuils à deux tambours, lesfortes potences de chalut et la conception améliorée des filets.
Per- and polyfluoroalkyl substances (PFAS) are a group of emerging substances that have proved to be persistent and highly bioaccumulative. They are broadly used in various applications and are known ...for their long-distance migration and toxicity. In this study, 65 recent specimens of a terrestrial apex predator (Common buzzard), freshwater and marine apex predators (Eurasian otter, harbour porpoise, grey seal, harbour seal) and their potential prey (bream, roach, herring, eelpout) from northern Europe (United Kingdom, Germany, the Netherlands and Sweden) were analyzed for the presence of legacy and emerging PFAS, employing a highly sensitive liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method. 56 compounds from 14 classes were measured; 13 perfluoroalkyl carboxylic acids (PFCAs), 7 perfluoroalkyl sulphonic acids (PFSAs), 3 perfluorooctane sulfonamides (FOSAs), 4 perfluoroalkylphosphonic acids (PFAPAs), 3 perfluoroalkylphosphinic acids (PFPi's), 5 telomer alcohols (FTOHs), 2 mono-substituted polyfluorinated phosphate esters (PAPs), 2 di-substituted polyfluorinated phosphate esters (diPAPs), 6 saturated fluorotelomer acids (FTAS), 3 unsaturated fluorotelomer acids (FTUAs), 2 N-Alkyl perfluorooctane sulfonamidoethanols (FOSEs), 3 fluorotelomer sulphonic acids (FTSAs), 2 perfluoroether carboxylic acids (PFECAs) and 1 chlorinated perfluoroether sulphonic acid (Cl-PFESA). All samples were lyophilized before analysis, in order to enhance extraction efficiency, improve the precision and achieve lower detection limits. The analytes were extracted from the dry matrices through generic methods of extraction, using an accelerated solvent extraction (ASE), followed by clean-up through solid phase extraction (SPE). Method detection limits and method quantification limits ranged from 0.02 to 1.25 ng/g wet weight (ww) and from 0.05 to 3.79 ng/g (ww), respectively. Recovery ranged from 40 to 137%. Method precision ranged from 3 to 20 %RSD. The sum of PFAS concentration in apex predators livers ranged from 0.2 to 20.2 μg/g (ww), whereas in the fish species muscle tissues it ranged from 16 to 325 ng/g (ww). All analyzed specimens were primarily contaminated with PFOS, while the three PFPi's included in this study exhibited frequency of appearance (FoA) 100 %. C9 to C13 PFCAs were found at high concentrations in apex predator livers, while the overall PFAS levels in fish fillets also exceeded ecotoxicological thresholds. The findings of our study show a clear association between the PFAS concentrations in apex predators and the geographical origin of the specimens, with samples that were collected in urban and agricultural zones being highly contaminated compared to samples from pristine or semi-pristine areas. The high variety of PFAS and the different PFAS composition in the apex predators and their prey (AP&P) samples is alarming and strengthens the importance of PFAS monitoring across the food chain.
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•PFAS were determined for marine, freshwater and terrestrial apex predators.•ΣPFAS concentrations were one to four orders of magnitude higher in apex predators.•PFOS, long-chain PFCAs and PFPi's were detected in all species studied.•PFAS concentrations were highest in Eurasian otters.•First report of F–53B in Eurasian otters.
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