Conservation of Amazonian manatee (Sirenia: Trichechidae): the case of Extractive Reserve Verde para Sempre, Brazil

Abstract

Found in the main rivers of the Amazon Basin, the Amazonian manatee (Trichechus inunguis) is the largest aquatic freshwater mammal in South America. The objective of this study was to describe the ecological knowledge and uses of the Amazonian manatee in the Extractive Reserve Verde para Sempre, Porto de Moz, Brazilian Amazon. This study was conducted through semi-structured interviews, free interviews, participant observation and image capture. Thirty-one residents were interviewed in 21 communities, using snowball sampling method. The interviewees were previously identified by local informants and selected according to their level of knowledge of the species. We collected information on the morphology, behavioral characteristics and feeding habits of manatees, and on the uses of the species by communities. Our findings suggest three hypotheses on the biology of Amazonian manatee: 1-the existence of three phenotypic patterns based on skin color and amount of fat; 2-changes in land use by agriculture, livestock and the installation of the hydroelectric plant affect their spatial distribution and seasonal migration; 3-they show reproductive behavior during the rainy season, in a polygamous way as a strategy of maintenance and genetic variability of the species. One third of the interviewees learned of the prohibition of manatee poaching during the implementation of the reserve. Poaching and consumption of manatees are rare, and entanglement of calves in fishing nets is accidental. These results reinforce the interest of local ecological knowledge in understanding the biology of the Amazonian manatee and their contribution to the delimitation of protected areas.

Cultivated Manatee Meat Aiding Amazon Biodiversity Conservation: Discussing a Proposed Model

“…Therefore, the return of those royalties to monitor the entire animal habitat would not be manageable. These observations are supported by the previous literature regarding the rainforest [24,60].…”

“…Even though hunting manatee has been illegal in Brazil since 1987, poaching has never ceased, resulting in the species becoming endangered. Consequently, several conservation institutions have striven to protect the Amazon's flora and fauna and the entire surrounding ecosystems [22][23][24].…”

Establishment and Characterization of a Primary Fibroblast Cell Culture from the Amazonian Manatee (Trichechus inunguis)

“…There are two species of manatees present in Brazil, T. inunguis and T. manatus (Antillean manatee), both coexisting in sympatry in the estuary of the Amazon basin, with reported cases of hybridization manatees in this region [ 2 , 3 , 4 ]. Currently, the Amazonian manatee is classified as vulnerable on the Red List of Threatened Species [ 5 ], with major threats arising from direct and indirect human activities, such as accidental captures of calves in fishing nets, strandings (especially during the rainy season), water pollution from pesticide and heavy metal use, deforestation of riparian forests due to inappropriate land use for agriculture, dam construction, livestock, and mining [ 6 , 7 , 8 ].…”

Quantifying minimum survey effort to reliably detect Amazonian manatees using an unoccupied aerial vehicle (UAV) at an ex situ soft-release site

“…To address the challenges of directly detecting Amazonian manatees, researchers primarily rely on alternative methods to visual observations to advance scientific knowledge about the species' biology and conservation, such as community surveys (Hoffmann et al, 2021), indirect signs of presence (i.e., feeding signals or feces; de Souza et al, 2021), active acoustics such as side-scan sonar (Gonzalez-Socoloske et al, 2009;Ruano et al, 2021;Gonzalez-Socoloske & Olivera-Gómez, 2023), and radio-tracking (Montgomery et al, 1981;Arraut et al, 2010;Landeo-Yauri et al, 2017;Guzmán Téllez, 2020). Indirect signs of Amazonian manatee presence, such as feeding signals, are easier to detect in comparison to directly detecting animals (Timm et al, 1986;de Souza et al, 2021).…”