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Burgess, Elizabeth A.; Lanyon, Janet M.; Brown, Janine L.; Blyde, David; Keeley, Tamara
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2012 |
Diagnosing pregnancy in free-ranging dugongs using fecal progesterone metabolite concentrations and body morphometrics: a population application.
General and Comparative Endocrinology 177(1): 82-92. 2 tabs. 8 figs. DOI: 10.1016/j.ygcen.2012.02.008. May 15, 2012.
–ABSTRACT: Assessing reproductive status and monitoring reproductive rates is important in the effective management of vulnerable marine mammal species such as the dugong (Dugong dugon). Knowledge of the reproductive physiology of this species is limited, and determining reproductive parameters (e.g., sexual maturation, pregnancy, and reproductive senescence) has been restricted by a lack of non-lethal methods for assessing reproductive status in free-ranging individuals. The aim of this study was to develop a method to identify pregnant individuals in a wild dugong population. Using an enzyme immunoassay, we quantified concentrations of fecal progesterone metabolites (fP) in 322 dugongs, including confirmed pregnant females (n=10), presumed non-pregnant adult females (n=25), juvenile females (n=24), subadult females (n=41), adult females of unknown pregnancy state (n=63), and males of all sizes (n=159). External body morphometrics of each dugong were measured, and confirmation of pregnancy in adult female dugongs was determined by ultrasonography or observation of subsequent neonates. Concentrations of fP were different between sexes and reproductive size classes (P<0.001), and similar to 30-fold higher in confirmed pregnant dugongs (2017-7760ng/g) compared to presumed non-pregnant females (30-221ng/g), juvenile females (29-195ng/g), and males (24-261ng/g) (P<0.001). Body measures of maximum and anal girths, and teat length were all greater in confirmed pregnant females than presumed non-pregnant females (all P<0.05). We evaluated a Discriminant Function Analysis (DFA) to provide a model for predicting pregnant and non-pregnant dugongs. Cross-validated results showed that the DFA correctly classified 100% of pregnant and non-pregnant females using fP concentrations, body length, fineness ratio (an index of body shape), and teat length (a female reproductive trait). Using the DFA model, we classified the pregnancy status of all female dugongs and identified a total of 30 females as pregnant and 133 females as non-pregnant from the sampled population over the sample period. Pregnant dugongs in the Moreton Bay population are characterized by fecal progesterone metabolite concentrations>1000ng/g, body length>=260cm, maximum girth>=215cm, anal girth>=126cm, and teat length>=5cm long. In summary, analysis of fP concentrations in combination with body morphometrics may be used to diagnose pregnancy in free-ranging dugongs, and provides a new tool to monitor breeding rates of wild sirenian populations.
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Walsh, Michael T.; Blyde, David J.
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2017 |
Sirenian health and well-being in managed care. Chap. 20 in: Andy Butterworth (ed.), Marine mammal welfare: human induced change in the marine environment and its impacts on marine mammal welfare.
Springer International Publishing: Animal Welfare Series, Vol. 17: 359-380. doi:10.1007/978-3-319-46994-2. June 20, 2017.
–ABSTRACT: The recorded history of Sirenia species in managed care is short and quite variable with many areas of early efforts poorly documented with anecdotal material. The three extant Sirenia species of the Trichechidae family and the one extant species of the Dugongidae family are all listed as threatened by the IUCN (International Union for the Conservation of Nature). Initially hunted as a source of food in many locations, our understanding of their physiology, history, and role in the environment was slow to develop. Early literature on human interaction contributed by scientists, anatomists, and the curiosity of those who wished to share their involvement with the species was fragmented but important. Managed care of Sirenia in zoos and aquariums was initially catalyzed by a desire to show these strange animals to the public, but has morphed into a developing concern for the conservation of Sirenia populations. Public and scientific concern for the species led to protective measures in some of their ecosystems with improvements in our understanding of their biology, genetics, reproduction, disease challenges, and the influence of humans on their welfare. This evolution of public involvement led to rescue and rehabilitation efforts by aquariums, zoos, state, and federal agencies to intervene in individual animal health. Research into human mortality causes also supported better documentation of natural illnesses that affect the population's survival. The Florida manatee rehabilitation programs and Australian dugong efforts illustrate the intersection of science, medicine, and ecosystem health in advocating the needs of these unique animals and what is required to support their survival and encourage recovery. As we intersect with Sirenia in rehabilitation and exhibit exposure for encouraging public support, it is important to provide suitable habitats for health and welfare and design their environments to their special needs while increasing protection of the wild habitats.
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Bibliography and Index of the Sirenia and Desmostylia 