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Ramos, Eric Angel; Martínez, Nataly Castelblanco; Niño-Torres, Carlos A.; Gomez, Nicole Auil
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2016 |
A review of the aquatic mammals of Belize.
Aquatic Mammals 42(4): 476-493. 2 figs. 1 tab. DOI 10.1578/AM.42.4.2016.476
–ABSTRACT: Characterizing species occurrence, abundance, and distribution is critical to the management of natural resources and the conservation of biodiversity. In the Western Caribbean, little information exists on the occurrence of aquatic mammals along the Mesoamerican Barrier Reef System and adjacent aquatic ecosystems. Herein, we present the first comprehensive review of aquatic mammals encountered in the marine and freshwater habitats of Belize. To determine which aquatic mammal species occur in Belizean waters, we conducted an extensive review of published and unpublished reports of aquatic mammals. We located 163 unique reports from museum and animal collections, journal articles, theses, news reports, conference proceedings, institutional reports, and verified accounts from personal observations. Our review confirms the presence of 17 aquatic mammal species in Belize: 15 cetaceans (Megaptera novaeangliae, Balaenoptera physalus, Ziphius cavirostris, Physeter macrocephalus, Kogia breviceps, Orcinus orca, Pseudorca crassidens, Globicephala macrorhynchus, Peponocephala electra, Stenella attenuata, S. clymene, S. frontalis, S. longirostris, Steno bredanensis, and Tursiops truncatus), one sirenian (Trichechus manatus manatus), and one carnivore (Lontra longicaudis annectens). Our findings provide the most up-to-date list of aquatic mammal presence in Belize. Given the limited data points obtained for most identified species, we recommend that systematic studies be conducted to investigate the status of the variety of aquatic mammals in the region to effectively monitor populations and devise strategies to mitigate the negative impacts of anthropogenic activity and climate change-related ecosystem shifts.
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Ramos, Eric A.; Maloney, Brigid; Magnasco, Marcelo O.; Reisse, Diana
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2018 |
Bottlenose dolphins and Antillean manatees respond to small multi-rotor unmanned aerial systems.
Frontiers in Marine Sciences 5(316): 1-15. 4 tabs. 7 figs. + online supplementary material. doi:10.3389/fmars.2018.00316 Sept. 12, 2018.
–ABSTRACT: Unmanned aerial systems (UASs) are powerful tools for research and monitoring of wildlife. However, the effects of these systems on most marine mammals are largely unknown, preventing the establishment of guidelines that will minimize animal disturbance. In this study, we evaluated the behavioral responses of coastal bottlenose dolphins (Tursiops truncatus) and Antillean manatees (Trichechus manatus manatus) to small multi-rotor UAS flight. From 2015 to 2017, we piloted 211 flights using DJI quadcopters (Phantom II Vision +, 3 Professional and 4) to approach and follow animals over shallow-water habitats in Belize. The quadcopters were equipped with high-resolution cameras to observe dolphins during 138 of these flights, and manatees during 73 flights. Aerial video observations of animal behavior were coded and paired with flight data to determine whether animal activity and/or the UAS's flight patterns caused behavioral changes in exposed animals. Dolphins responded to UAS flight at altitudes of 11–30 m and responded primarily when they were alone or in small groups. Single dolphins and one pair responded to the UAS by orienting upward and turning toward the aircraft to observe it, before quickly returning to their pre-response activity. A higher number of manatees responded to the UAS, exhibiting strong disturbance in response to the aircraft from 6 to 104 m. Manatees changed their behavior by fleeing the area and sometimes this elicited the same response in nearby animals. If pursued post-response, manatees repeatedly responded to overhead flight by evading the aircraft's path. These findings suggest that the invasiveness of UAS varies across individuals, species, and taxa. We conclude that careful exploratory research is needed to determine the impact of multi-rotor UAS flight on diverse species, and to develop best practices aimed at reducing the disturbance to wildlife that may result from their use.
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Landeo-Yauri, Sarah Sofía; Ramos, Eric Angel; Castelblanco-Martínez, Delma Nataly; Niño-Torres, Carlos Alberto; Searle, Linda
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2020 |
Using small drones to photo-identify Antillean manatees: a novel method for monitoring an endangered marine mammal in the Caribbean Sea.
Endangered Species Research 41: 79-90. 2 tabs. 5 figs. doi.org/10.3354/esr01007 Jan. 30, 2020.
–ABSTRACT: Population assessments and species monitoring for many endangered marine megafauna are limited by the challenges of identifying and tracking individuals that live underwater in remote and sometimes inaccessible areas. Manatees can acquire scars from watercraft injury and other incidences that can be used to identify individuals. Here we describe a novel method for photo-identification of Antillean manatees Trichechus manatus manatus using aerial imagery captured during flights with a small multirotor drone. Between 2016 and 2017, we conducted 103 flights to detect and observe manatees in Belize, primarily at St. George's Caye (SGC) near the Belize Barrier Reef. Review of aerial videos from these flights resulted in 279 sightings of manatees (245 adults, 34 calves). High-resolution images of individual manatees were extracted and classified according to image quality and distinctiveness of individual manatees for photo-identification. High-quality images of manatees classified as sufficiently distinctive were used to create a catalog of 17 identifiable individuals. At SGC, 21% of all sighted adult manatees (N = 214) were considered photo-identifiable over time. We suggest that the method can be used for investigating individual site fidelity, habitat use, and behavior of manatee populations. Our photo-identification protocol has the potential to improve long-term monitoring of Antillean manatees in Belize and can be applied throughout clear, shallow waters in the Caribbean and elsewhere.
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Ramos, Eric Angel; Maust-Mol, Maria; Collom, Kristi A.; Brady, Beth; Gerstein, Edmund R.; Magnasco, Marcelo O.; Reiss, Diana
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2020 |
The Antillean manatee produces broadband vocalizations with ultrasonic frequencies.
Journal of the Acoustical Society of America 147(2): EL80-EL86. 1 tab. 3 figs. doi.org/10.1121/10.0000602 Feb. 5, 2020.
–ABSTRACT: Antillean manatees produce vocalizations reported to be important for communication, but their vocal behavior throughout their geographic range is poorly understood. A SoundTrap recorder (sample rates: 288/576?kHz) was deployed in Belize to record vocalizations of wild manatees in a seagrass channel and of a young rehabilitated and released manatee in a shallow lagoon. Spectral analysis revealed broadband vocalizations with frequencies up to 150?kHz and a high proportion of calls with ultrasonic components. Ultrasonic frequency components appear prevalent in their vocal repertoire and may be important to manatee communication.
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Tennant, Rachel; Brady, Beth; Love, Kim; Ramos, Eric; Schloesser, Ryan
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2024 |
Persistent long-term habitat use by Florida manatees at Fort Pierce, Florida from 1997 to 2020.
PlosOne https://doi.org/10.1371/journal.pone.0297636. 7 tabs. 5 figs. Mar. 21, 2024.
–ABSTRACT: To survive cold winters, Florida manatees (Trichechus manatus latirostris) depend on artificial (i.e., power plants) and natural warm water sources such as springs and passive thermal basins. Passive thermal basins can provide critical habitat for manatees for short or extended periods of time. The Henry D. King Powerplant in Fort Pierce, Florida discharged warm water into Moore's Creek until it went offline in 1995. However, it is unknown to what degree manatees continue to occupy this area and how environmental factors influence their occurrence in the creek. To explore this, we examined the habitat use of Florida manatees in Moore's Creek after the shutdown from November 1997 to March 2020 from daily counts of manatees. In addition, we correlated local environmental data (ambient air, temperature, salinity) to assess if Moore's Creek had properties indicative of a passive thermal basin. Results indicated there was not an increase or decrease in habitat use over twenty years in the Creek. The consistent use of Moore's Creek over the study period suggests that this habitat possesses thermal and freshwater resources to support manatee occurrence long-term. These findings provide robust support for the importance of this habitat and passive thermal basins for Florida manatees.
--Review: Ryan Schloesser, Aquatic Mammals, 2004.
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Bibliography and Index of the Sirenia and Desmostylia 