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Landeo-Yauri, Sarah Sofía; Castelblanco-Martínez, Delma Nataly; Williams, Martha
(detail)
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2017 |
Behavior and habitat use of released rehabilitated Amazonian manatees in Peru.
Latin Amer. Jour. Aquat. Mamms. 12(1-2): 17-27. 3 tabs. 5 figs. https://doi.org/10.5597/lajam00234. Dec. 30, 2017.
–ABSTRACT: The Amazonian manatee (Trichechus inunguis) is endangered due to illegal hunting. In Peru, the Centro de Rescate Amazónico (CREA) rehabilitates and releases rescued manatees. Three females and two males were released in El Dorado Lake in July 2011 and radio tracked until November 2011. Movements, habitat use and behavior recorded during the post-release period were used to evaluate the manatees' adaptation to free-living conditions. A total of 140 locations was registered during 91 days of tracking. Females showed greater residence time than males, which migrated out of the lake. Females selectively used the micro habitats of the study area, preferring floating vegetation, followed by open water and lastly shore macrophytes. Most idling behaviors were registered in areas with floating macrophytes, and open water was mainly used for traveling. No correlation between sighting hour and sighting location (micro habitat type) was detected. The use of suitable zones, in addition to natural behavior, suggests that these rescued manatees responded well to free-living conditions after release. Some considerations are provided with the purpose of strengthening manatee rehabilitation programs and improving future releases, emphasizing the importance of choosing appropriate individuals, as well as suitable areas and times to help improve release outcome.
RESUMEN: El manatí amazónico (Trichechus inunguis) es una especie amenazada, principalmente debido a la caza ilegal. En Perú, el Centro de Rescate Amazónico (CREA) desarrolla esfuerzos para rehabilitar manatíes rescatados y liberarlos posteriormente a la vida silvestre. Tres hembras y dos machos fueron liberados en la cocha El Dorado en julio del 2011, siendo rastreados mediante telemetría VHF hasta noviembre del mismo año. El monitoreo post liberación incluyó el registro de los desplazamientos, uso de hábitat y comportamiento de los animales, con el fin de evaluar su adaptación a las condiciones de vida libre. A lo largo de 91 días de rastreo, se obtuvo un total de 140 localizaciones. Las hembras mostraron un mayor tiempo de residencia que los machos, quienes migraron fuera de la zona de liberación. También se determinó que las hembras usaron selectivamente los micro habitats en el área de estudio, prefiriendo zonas de vegetación flotante seguidas por aguas abiertas y finalmente orillas asociadas a vegetación. La mayoría de desplazamientos fueron observados en aguas abiertas, mientras que comportamientos de permanencia ocurrieron generalmente en vegetación flotante. No se encontró ninguna correlación entre el tipo de micro habitat ocupado y la hora del día. El uso selectivo de zonas adecuadas por parte de los individuos, sumado a reportes previos sobre el comportamiento de la especie en vida silvestre, sugiere que los manatíes liberados tuvieron una respuesta positiva a las condiciones del medio natural. Se incluyen algunas recomendaciones con el fin de fortalecer programas de rehabilitación y mejorar futuras liberaciones, enfatizando la importancia de seleccionar adecuadamente los individuos a ser liberados, así como las áreas y tiempos de liberación.
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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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Bibliography and Index of the Sirenia and Desmostylia 