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Gibbs, Melissa; Futral, Tiffany; Mallinger, Megan; Martin, Desiree; Ross, Monica
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2010 |
Disturbance of the Florida manatee by an invasive catfish.
Southeastern Naturalist 9(4): 635-648. 2 tabs. 3 figs. DOI: 10.1656/058.009.0401.
–ABSTRACT: During the winter, Trichechus manatus latirostris (Florida manatee) depends on long periods of rest in comparatively warm thermal refuges to help conserve energy and maintain stable body temperatures. Pterygoplichthys disjunctivus (Vermiculated Suckermouth Sailfin Catfish) has been observed attached to, and grazing algae from, Florida manatees in Volusia Blue Spring. We hypothesized that the disturbance caused by grazing armored catfish would significantly alter Florida manatee behavior. Analyses of 6 hours of underwater video of Florida manatee behavior, with and without attached armored catfish, revealed that during each observation period, Florida manatees with attached catfish demonstrated significantly higher activity levels and numbers of active behaviors. Increased Florida manatee activity caused by the armored catfish may compound the impact of other known threat effects.
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Martin, Julien; Edwards, Holly H.; Bled, Florent; Fonnesbeck, Christopher J.; Dupuis, Jérôme A.; Gardner, Beth; Koslovsky, Stacie M.; Aven, Allen M.; Ward-Geiger, Leslie I.; Carmichael, Ruth H.; Fagan, Daniel E.; Ross, Monica A.; Reinert, Thomas R.
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2014 |
Estimating upper bounds for occupancy and number of manatees in areas potentially affected by oil from the Deepwater Horizon oil spill.
PLoS ONE 9(3): e91683. 6pp. 1 tab. 2 figs. DOI: 10.1371/journal.pone.0091683. Mar. 26, 2014.
–ABSTRACT: The explosion of the Deepwater Horizon drilling platform created the largest marine oil spill in U.S. history. As part of the Natural Resource Damage Assessment process, we applied an innovative modeling approach to obtain upper estimates for occupancy and for number of manatees in areas potentially affected by the oil spill. Our data consisted of aerial survey counts in waters of the Florida Panhandle, Alabama and Mississippi. Our method, which uses a Bayesian approach, allows for the propagation of uncertainty associated with estimates from empirical data and from the published literature. We illustrate that it is possible to derive estimates of occupancy rate and upper estimates of the number of manatees present at the time of sampling, even when no manatees were observed in our sampled plots during surveys. We estimated that fewer than 2.4% of potentially affected manatee habitat in our Florida study area may have been occupied by manatees. The upper estimate for the number of manatees present in potentially impacted areas (within our study area) was estimated with our model to be 74 (95% CI 46 to 107). This upper estimate for the number of manatees was conditioned on the upper 95% CI value of the occupancy rate. In other words, based on our estimates, it is highly probable that there were 107 or fewer manatees in our study area during the time of our surveys. Because our analyses apply to habitats considered likely manatee habitats, our inference is restricted to these sites and to the time frame of our surveys. Given that manatees may be hard to see during aerial surveys, it was important to account for imperfect detection. The approach that we described can be useful for determining the best allocation of resources for monitoring and conservation.
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Adimey, Nicole M.; Ross, Monica; Hall, Madison; Reid, James P.; Barlas, Margaret E.; Keith Diagne, Lucy W.; Bonde, Robert K.
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2016 |
Twenty-six years of post-release monitoring of Florida manatees (Trichechus manatus latirostris): evaluation of a cooperative rehabilitation program.
Aquatic Mamms. 42(3): 376-391. 3 tabs. 5 figs. DOI 10.1578/AM.42.3.2016.376.
–ABSTRACT: The rescue, rehabilitation, and release of Florida manatees (Trichechus manatus latirostris) into the wild has occurred since 1974; however, a comprehensive evaluation of the outcomes of the releases has never been conducted. Herein, we examined data for 136 Florida manatees that were rehabilitated and released with telemetry tags between 1988 and 2013 to determine release outcome of each individual as either success (acclimation) or failure after at least 1 y. Ten predictor variables were statistically evaluated for potential relationships to release outcome. To assess the contribution of each predictor variable to release outcome, each variable was tested for significance in univariate analyses. Manatees born in captivity experienced poor success after release (14%), whereas the overall success of wild-born individuals was higher (72%). When compared with other variables in our dataset, number of days in captivity was the strongest predictor for determining success. Manatees rescued as calves and held in captivity for more than 5 y had a high likelihood of failure, while subadults and adults had a high likelihood of success, regardless of the amount of time spent in captivity. Ensuring the success of individual manatees after release is critical for evaluating the contribution of the manatee rehabilitation program to the growth of the wild population.
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De María, Maite; Silva-Sanchez, Cecilia; Kroll, Kevin J.; Walsh, Michael T.; Nouria, Mohammad-Zaman; Hunter, Margaret E.; Ross, Monica; Clauss, Tonya M.; Denslow, Nancy D.
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2021 |
Chronic exposure to glyphosate in Florida manatee.
Environment International 152: 3 tabs. 3 figs. https://doi.org/10.1016/j.envint.2021.106493 July 2021.
–ABSTRACT: Florida manatees depend on freshwater environments as a source of drinking water and as warm-water refuges. These freshwater environments are in direct contact with human activities where glyphosate-based herbicides are being used. Glyphosate is the most used herbicide worldwide and it is intensively used in Florida as a sugarcane ripener and to control invasive aquatic plants. The objective of the present study was to determine the concentration of glyphosate and its breakdown product, aminomethylphosphonic acid (AMPA), in Florida manatee plasma and assess their exposure to manatees seeking a warm-water refuge in Crystal River (west central Florida), and in South Florida. We analyzed glyphosate's and AMPA's concentrations in Florida manatee plasma (n = 105) collected during 2009–2019 using HPLC-MS/MS. We sampled eight Florida water bodies between 2019 and 2020, three times a year: before, during and after the sugarcane harvest using grab samples and molecular imprinted passive Polar Organic Chemical Integrative Samplers (MIP-POCIS). Glyphosate was present in 55.8% of the sampled Florida manatees' plasma. The concentration of glyphosate has significantly increased in Florida manatee samples from 2009 until 2019. Glyphosate and AMPA were ubiquitous in water bodies. The concentration of glyphosate and AMPA was higher in South Florida than in Crystal River, particularly before and during the sugarcane harvest when Florida manatees depend on warm water refuges. Based on our results, Florida manatees were chronically exposed to glyphosate and AMPA, during and beyond the glyphosate applications to sugarcane, possibly associated with multiple uses of glyphosate-based herbicides for other crops or to control aquatic weeds. This chronic exposure in Florida water bodies may have consequences for Florida manatees' immune and renal systems which may further be compounded by other environmental exposures such as red tide or cold stress.
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Bibliography and Index of the Sirenia and Desmostylia 