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Takeuchi, Noel; Walsh, Michael T.; Bonde, Robert K.; Powell, James A.; Bass, Dean A.; Gaspard, Joseph C., III; Barber, David S.
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2016 |
Baseline reference range for trace metal concentrations in whole blood of wild and managed West Indian manatees (Trichechus manatus) in Florida and Belize.
Aquatic Mammals 42(4): 440-453. 5 tabs. doi:10.1578/AM.42.4.2016.440. Dec. 2016.
–ABSTRACT: The West Indian manatee (Trichechus manatus) is exposed to a number of anthropogenic influences, including metals, as they inhabit shallow waters with close proximity to shore. While maintaining homeostasis of many metals is crucial for health, there is currently no baseline reference range that can be used to make clinical and environmental decisions for this endangered species. In this study, whole blood samples from 151 manatees were collected during health assessments performed in Florida and Belize from 2008 through 2011. Whole blood samples (n = 37) from managed care facilities in Florida and Belize from 2009 through 2011 were also used in this study. The concentrations of 17 metals in whole blood were determined, and the data were used to derive a baseline reference range. Impacts of capture location, age, and sex on whole blood metal concentrations were examined. Location and age were related to copper concentrations as values were significantly higher in habitats near urban areas and in calves. Copper may also be a husbandry concern as concentrations were significantly higher in managed manatees (1.17 ± 0.04 ppm) than wild manatees (0.73 ± 0.02 ppm). Zinc (11.20 ± 0.30 ppm) was of special interest as normal concentrations were two to five times higher than other marine mammal species. Arsenic concentrations were higher in Belize (0.43 ± 0.07 ppm), with Placencia Lagoon having twice the concentration of Belize City and Southern Lagoon. Selenium concentrations were lower (0.18 ± 0.09 ppm) than in other marine mammal species. The lowest selenium concentrations were observed in rehabilitating and managed manatees which may warrant additional monitoring in managed care facilities. The established preliminary baseline reference range can be used by clinicians, biologists, and managers to monitor the health of West Indian manatees.
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Allen, Aarin Conrad; Beck, Cathy A.; Bonde, Robert K.; Powell, James A.; Auil Gomez, Nicole
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2017 |
Diet of the Antillean manatee (Trichechus manatus manatus) in Belize, Central America.
Jour. Marine Biological Association of the United Kingdom 98(7): 1831-1840. 2 tabs. 1 fig. 8 appendices. doi:/10.1017/S0025315417000182 Nov. 2018 (publ. online Apr. 3, 2017).
–ABSTRACT: Belize contains important habitat for Antillean manatees (Trichechus manatus manatus) and provides refuge for the highest known population density of this subspecies. As these animals face impending threats, knowledge of their dietary habits can be used to interpret resource utilization. The contents of 13 mouth, six digestive tract (stomach, duodenum and colon) and 124 faecal samples were microscopically examined using a modified point technique detection protocol to identify key plant species consumed by manatees at two important aggregation sites in Belize: Southern Lagoon and the Drowned Cayes. Overall, 15 different items were identified in samples from manatees in Belize. Five species of seagrasses (Halodule wrightii, Thalassia testudinum, Ruppia maritima, Syringodium filiforme and Halophila sp.) made up the highest percentage of items. The red mangrove (Rhizophora mangle) was also identified as an important food item. Algae (Ulva sp., Chara sp., Lyngbya sp.) and invertebrates (sponges and diatoms) were also consumed. Variation in the percentage of seagrasses, other vascular plants and algae consumption was analysed as a 4-factor analysis of variance (ANOVA) with main effects and interactions for locality, sex, size classification and season. While sex and season did not influence diet composition, differences for locality and size classification were observed. These results suggest that analysis of diet composition of Antillean manatees may help to determine critical habitat and use of associated food resources which, in turn, can be used to aid conservation efforts in Belize.
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Alvarez-Alemán, Anmari; Alfonso, Eddy García; Forneiro Martin-Vianna, Yanet; Hernández Gonzalez, Zaimiuri; Domenech, Raisa Escalona; Hurtado, Andrés; Powell, James A.; Jacoby, Charles A.; Frazer, Thomas K.
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2018a |
Status and conservation of manatees in Cuba: historical observations and recent insights.
Bull. Marine Science 94(2): 313-327. https://doi.org/10.5343/bms.2016.1132 April 2018.
–ABSTRACT: The Antillean manatee (Trichechus manatus manatus Linnaeus, 1758) is classified as endangered by the International Union for Conservation of Nature because of reduced numbers and habitat loss. Existing information about this species in Cuba is limited, but it can be synthesized into useful guidance for strategies to protect and rehabilitate this population. Anthropogenic threats have been reported to have had detrimental effects on manatees since 1970, with a major factor being illegal hunting. Information obtained through interviews of fishers, and boat and aerial surveys has identified the Ensenada de la Broa and Hatiguanico River on the Zapata Peninsula as important areas for manatees. Historically, manatees frequented rivers and other freshwater habitats, but currently they are encountered primarily in estuarine and coastal waters, which makes availability of fresh water an important consideration. There is a pressing need to gather additional and more reliable data on the abundance, distribution, and health of Antillean manatees in Cuba as a basis for more effective and efficient initiatives to protect and rehabilitate this population.
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Alvarez-Aleman, Anmari; Hunter, Margaret E.; Frazer, Thomas K.; Powell, James A.; Garcia-Alfonso, Eddy; Austin, James D.
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2022 |
The first assessment of the genetic diversity and structure of the endangered West Indian manatee in Cuba.
Genetica 150: 327-341. Oct. 22, 2022.
–ABSTRACT: The coastal waters of Cuba are home to a small, endangered population of West Indian manatee, which would benefit from a comprehensive characterization of the population's genetic variation. We conducted the first genetic assessment of Cuban manatees to determine the extent of the population's genetic structure and characterize the neutral genetic diversity among regions within the archipelago. We genotyped 49 manatees at 18 microsatellite loci, a subset of 27 samples on 1703 single nucleotide polymorphisms (SNPs), and sequenced 59 manatees at the mitochondrial control region. The Cuba manatee population had low nuclear (microsatellites HE=0.44, and SNP HE=0.29) and mitochondrial genetic diversity (h=0.068 and pi=0.00025), and displayed moderate departures from random mating (microsatellite FIS=0.12, SNP FIS=0.10). Our results suggest that the western portion of the archipelago undergoes periodic exchange of alleles based on the evidence of shared ancestry and low but significant differentiation. The southeast Guantanamo Bay region and the western portion of the archipelago were more differentiated than southwest and northwest manatees. The genetic distinctiveness observed in the southeast supports its recognition as a demographically independent unit for natural resource management regardless of whether it is due to historical isolation or isolation by distance. Estimates of the regional effective population sizes, with the microsatellite and SNP datasets, were small (all Ne<60). Subsequent analyses using additional samples could better examine how the observed structure is masking simple isolation by distance patterns or whether ecological or biogeographic forces shape genetic patterns.
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