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Lanyon, Janet M.; Sneath, Helen L.; Long, Trevor; Bonde, Robert K.
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2010 |
Physiological response of wild dugongs (Dugong dugon) to out-of-water sampling for health assessment.
Aquatic Mammals 36(1): 46-58. 2 tabs. 5 figs. DOI: 10.1578/AM.36.1.2010.46. Jan. 2010.
–ABSTRACT: The dugong (Dugong dugon) is a vulnerable marine mammal with large populations living in urban Queensland waters. A mark-recapture program for wild dugongs has been ongoing in southern Queensland since 2001. This program has involved capture and in-water sampling of more than 700 dugongs where animals have been held at the water surface for 5 min to be gene-tagged, measured, and biopsied. In 2008, this program expanded to examine more comprehensively body condition, reproductive status, and the health of wild dugongs in Moreton Bay. Using Sea World's research vessel, captured dugongs were lifted onto a boat and sampled out-of-water to obtain accurate body weights and morphometrics, collect blood and urine samples for baseline health parameters and hormone profiles, and ultrasound females for pregnancy status. In all, 30 dugongs, including two pregnant females, were sampled over 10 d and restrained on deck for up to 55 min each while biological data were collected. Each of the dugongs had their basic temperature-heart rate-respiration (THR) monitored throughout their period of handling, following protocols developed for the West Indian manatee (Trichechus manatus). This paper reports on the physiological response of captured dugongs during this out-of-water operation as indicated by their vital signs and the suitability of the manatee monitoring protocols to this related sirenian species. A recommendation is made that the range of vital signs of these wild dugongs be used as benchmark criteria of normal parameters for other studies that intend to sample dugongs out-of-water.
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Lanyon, Janet M.; Sneath, Helen L.; Long, Trevor
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2012 |
Evaluation of exertion and capture stress in serum of wild dugongs (Dugong dugon).
Jour. Zoo & Wildlife Medicine 43(1): 20–32. 2 tabs. 2 figs.
–ABSTRACT: Seven hundred fifty-one dugongs (Dugong dugon) were pursued, captured, and handled for up to 20 min for population sampling. Fifty of these dugongs were then removed from the water for up to 55 min for comprehensive medical examination. Fifty whole blood and separated serum samples were analyzed for potassium, sodium, chloride, creatinine kinase (CK), aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), urea, creatinine, glucose, anion gap, and total blood CO2. Serum biochemical variables of the dugong were compared with those obtained in previous studies of the related West Indian manatee, a mammal that does not appear to experience capture myopathy based on available data. Differences between these species included higher blood sodium and chloride in dugongs, which may reflect differences in salt balance and renal function, and higher blood lactate and CO2. Some biochemical analytes such as CK and AST, which may be indicative of rhabdomyolysis associated with capture stress myopathy (a potentially fatal condition for which dugongs have been thought to be highly susceptible) were high compared with levels previously measured in wild West Indian manatees (Trichechus latirostris). One of the 50 dugongs had marked elevations of CK and AST but showed no other clinical indications of rhabdomyolysis associated with capture myopathy such as hyperthermia. Rather, generally high levels of lactate, CK, and AST most probably reflect metabolic acidosis resulting from the exertion involved in the pursuit prior to capture. Earlier observations suggesting that dugongs were probably susceptible to capture stress myopathy (based on high serum potassium levels) were not supported by this study. Capture and handling methods currently used on dugongs in this research program do not appear to result in acute capture stress.
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Lanyon, Janet M.; Wong, Arthur; Long, Trevor; Woolford, Lucy
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2015 |
Serum biochemistry reference intervals of live wild dugongs (Dugong dugon) from urban coastal Australia.
Veterinary Clinical Pathology DOI: 10.1111/vcp.12249. Publ. online April 3, 2015.
–ABSTRACT: Background: Little is known about the baseline clinical pathology of the dugong (Dugong dugon), a vulnerable marine mammal found in tropical coastal marine systems. Objectives: The purpose of the study was to collect and determine reference intervals (RI) for select serum biochemical variables for dugongs, and to analyze differences between males and females and different age groups. Methods: Reference intervals were established from 103 apparently healthy, wild-caught dugongs for 31 analytes using a Beckman Coulter AU400 Automated Chemistry Analyzer and an Olympus AU680 Chemistry-Immuno Analyzer. Results: Significant differences (P<.05) in some of the variables were found related to size class, sex, and pregnancy status. Adult dugongs had higher serum sodium, potassium, bicarbonate, glucose, and l-lactate concentrations and higher anion gap, compared to sub-adults. Male dugongs had higher triglyceride and l-lactate concentrations than females. Pregnant females displayed higher l-lactate levels compared to nonpregnant animals. Statistical differences in variables within the population contributed to better understanding of the physiologic differences between cohorts. Some serum biochemistry changes observed in this study here also potentially include some effects of pursuit on dugongs (e.g., higher l-lactate); however, as all dugongs were subject to similar capture and handling, serum biochemistry RI should be considered as normal for captured dugongs. Conclusions: The serum biochemical RI documented here are considered representative of a population of healthy captured dugongs. They provide a baseline for health surveillance of this and other dugong populations.
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Woolford, Lucy; Wong, Arthur; Sneath, Helen L.; Long, Trevor; Boyd, Susan P.; Lanyon, Janet M.
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2015 |
Hematology of dugongs (Dugong dugon) in southern Queensland.
Veterinary Clinical Pathology 44(4): 530–541. 6 tabs. 4 figs. DOI: 10.1111/vcp.12305. Dec. 2015.
–ABSTRACT: Background- Little is known of the hematology of the dugong (Dugong dugon), a secretive and endangered coastal marine mammal.
Objectives- This paper reports hematologic reference intervals (RI) for dugongs and characterizes morphologic, cytochemical, and ultrastructural features of dugong leukocytes.
Methods- Blood was collected from live, apparently healthy dugongs and analyzed using Cell-Dyn 3700 or Sysmex XT-2000iV hematology analyzers. Blood films were subjected to a series of cytochemical stains, and leukocyte structure was examined using transmission electron microscopy.
Results- Reference intervals were established for 14 hematologic variables, total solids, and fibrinogen for 92 dugongs. Significant differences in some variables were found for animal size class, sex, and pregnancy status, and between analyzers. Subadults had higher leukocyte and lymphocyte counts than adults. Males had higher total solids and fibrinogen than females. Pregnant females had higher HCT, MCV, and circulating nucleated RBC, and lower platelet counts than nonpregnant females. Lymphocytes were usually the predominant circulating leukocyte. Heterophil cytoplasmic granules were abundant, fine, round to ovoid, and intensely eosinophilic, and round to ovoid or rod-shaped, and variably electron dense in electron microscopy. Eosinophils contained larger round eosinophilic to orange cytoplasmic granules, which ultrastructurally were bicompartmental with a round eccentric electron-dense core. Cytochemical staining of dugong heterophils suggests biochemical similarity to those of manatees and elephants, and for eosinophils, similarity to those of elephants, ruminants, and equids.
Conclusions- Generation of hematologic RI and characterization of leukocyte morphology improves evaluation of dugong health across this population and serves as a reference for other populations outside southern Queensland.
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Wong, Arthur; Lanyon, Janet M.; McKee, Sara J.; Linedale, Richard; Woolford, Lucy; Long, Trevor; Leggatt, Graham R.
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2018 |
Development of a polyclonal anti-dugong immunoglobulin G (IgG) antibody with evaluation of total plasma IgG in a living dugong (Dugong dugon) population.
Veterinary Immunology & Immunopathology 200: 16-25. 2 tabs. 4 figs. DOI: 10.1016/j.vetimm.2018.04.003 Apr. 8, 2018.
–ABSTRACT: Species-specific antibodies (Ab) for the measurement of immunoglobulins (Ig) are valuable tools for determining the humoral immune status of threatened and endangered wildlife species such as dugongs. However, no studies have reported antibody reagents against dugong immunoglobulin. The object of this study was to develop an Ab with specificity for dugong IgG and apply this tool to survey total IgG levels in plasma samples from a live wild population of dugongs in southern Queensland, Australia. Dugong IgG was isolated from plasma by protein A/G column chromatography and a polyclonal antiserum was successfully raised against the dugong IgG through immunization of mice. The anti-dugong antiserum was reactive with dugong serum but not immunoglobulin from other species such as rats and humans. When tested against a panel of dugong plasma samples, relative IgG levels from dugongs (n?=?116) showed biologically relevant relationships with pregnancy status and a principal component of Body Mass Index (BMI)/globulin/fecal glucocorticosteroid (chronic stress) levels combined, which together accounted for 9.2% of the variation in total Ig levels. Together these data suggest that dugongs show variation in total IgG and that this correlates with some physiological parameters of dugong health.
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Wong, Arthur; Lanyon, Janet M.; O'Handley, Ryan; Linedale, Richard; Woolford, Lucy; Long, Trevor; Leggatt, Graham R.
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2019 |
Serum antibodies against Toxoplasma gondii and Neospora caninum in southeast Queensland dugongs.
Mar. Mamm. Sci. https://doi.org/10.1111/mms.12629. Jan. 2020; publ. online June 24, 2019.
–ABSTRACT: The dugong (Dugong dugon) is an herbivorous marine mammal that inhabits tropical inshore waters and thus may be vulnerable to pollutants and terrestrial pathogens as a result of coastal runoff. In this study, serum samples collected from live, wild dugongs (n = 114) in an embayment located on the urbanized southeast Queensland coast of Australia during 2008–2014, were measured for IgG antibody levels specific to Toxoplasma gondii and Neospora caninum. An ELISA used to measure T. gondii tachyzoite antibodies indicated a non-Gaussian distribution of antibody level, with five dugongs identified as high outliers. Mean levels of antibodies specific for T. gondii in dugongs sampled in 2014 were significantly higher than in 2010 (p=.006) and 2011 (p=.009) with an elevation in mean antibody levels after a major 2011 flood event relative to antibody levels prior to the flood (p<.0001). A competitive ELISA to detect N. caninum antibody indicated a normal distribution of antibody with no high outliers. Mean antibody level for N. caninum was highest in 2012 and declined significantly in 2014 (p=.004). This is the first survey of antibodies directed against T. gondii and N. caninum in dugongs and suggests future health monitoring of this species.
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Lanyon, Janet M.; Sneath, Helen L.; Long, Trevor; Blanshard, Graham A. J. Worthy, David T. Booth
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2024 |
How much seagrass does a dugong need? Metabolic rate of live wild dugongs, Dugong dugon, determined through indirect calorimetry (oxygen consumption).
Mar. Mamm. Sci. https://doi.org/10.1111/mms.13190 7 figs., 5 tables. Oct. 4, 2024.
–ABSTRACT: Deterioration of seagrass beds worldwide has raised concern about the future of dugongs because almost all aspects of their life history depend on availability of seagrass. Understanding their energy metabolism and consequently how much seagrass they need will inform protective conservation strategies for dugongs. This study determined resting metabolic rate (RMR) in five wild-caught adult dugongs by measuring oxygen consumption (O2). Measurement conditions met assumptions for RMR, except that dugongs were not postabsorptive, thus a postprandial (pp) allometric equation for herbivorous mammals of similar size was used to predict an expected RMRpp for dugongs of known mass. O2 was measured for 30 min. in a metabolic tank after brief habituation. Dugongs' RMRpp was approximately half that predicted for their body mass but was higher than for manatees. Based on dugongs' RMRpp and considering plant caloric and water content, the daily minimum intake of fresh weight seagrass was 40?65?kg Halophila ovalis, or 20?40?kg Halodule spp. Greater seagrass intake would be required for growing and reproducing dugongs. Slow growth and protracted reproductive rates of dugongs are likely related to limitations in seagrass energy and nutrients. To ensure viability of this vulnerable species, it is critically important to conserve extensive healthy seagrass beds.
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Bibliography and Index of the Sirenia and Desmostylia 