Latin American Journal of Aquatic Mammals (LAJAM)
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Where there’s smoke, there’s fire: Hypotheses for the high incidence of West Indian manatee calf strandings on the Brazilian semi-arid coast
No full textFranciscana, Pontoporia blainvillei, stranding records from systematic beach surveys, opportunistic and incidental capture reports at theRío Negro Estuary, Patagonia, Argentina (2003 – 2023)
No full textDetailed here are records of 34 franciscanas (Pontoporia blainvillei) that stranded, including nine rescued alive and returned to sea, from the Río Negro Estuary, Patagonia, Argentina, between 2003 and 2023. The years with the highest stranding records were 2014 and 2020 (n = 6/ each). Autumn and winter/spring were the seasons with the lowest and highest number of strandings, respectively. These strandings comprised 15 females, six males, and 13 unknowns. Total body length of females ranged from 64 to 155 cm and for males ranged from 70 to 138 cm. Five of the strandings involved calves and occurred within the birthing periods previously reported for the species at the Río Negro Estuary. A complete necropsy was performed on three animals. One showed multifocal pneumonic lesions from which Klebsiella pneumoniae was isolated and identified microbiologically. In a second specimen, Pseudomonas sp. and coagulase-negative Staphylococcus sp. were identified, and in a third individual tuberculosis caused by a member of the Mycobacterium tuberculosis complex was identified. Despite these results, it was not possible to be certain that they were the causes of death of these three individuals. Three franciscanas had beak deformities. A total of 79 otoliths representing 41 specimens of white croaker (Micropogonias furnieri) were found in one stomach content analyzed. Eleven franciscanas showed signs of having been bycaught (four with net marks, four entangled in gillnets or reported by the fishermen who bycaught them (n=3)). This is the first report of franciscana entanglements in sport fishing gear at the Río Negro Estuary. This paper provides information highlighted as important by the International Whaling Commission Conservation Management Plan for franciscana, and contributes to knowledge of the species in the Franciscana Management Area IVe.
Keywords: bycatch, calves, disease, fishing rods, gillnets, odontocete
Quantifying minimum survey effort to reliably detect Amazonian manatees using an unoccupied aerial vehicle (UAV) at an ex situ soft-release site
No full textDetection of many threatened aquatic mammals, such as manatees (Trichechus spp.), using traditional visual observation methods is associated with high uncertainty due to their low surfacing times, cryptic behaviors, and the environmental heterogeneity of their habitats. Rapid advancements in technology provide an opportunity to address these challenges. In this study, we aimed to quantify survey effort of unoccupied aerial vehicles (UAVs) for detecting the Vulnerable Amazonian manatee (T. inunguis). Using a closed population of manatees that is being rehabilitated within a lake at the Rainforest Awareness, Rescue, and Education Center in Iquitos, Peru, we calculated the number of repeat surveys needed to detect at least one individual with 95% (n = 3.10) and 99% (n = 4.76) confidence. We used both generalized linear mixed-effect models and Bayesian single-species and single-season detection models to determine the effects of the environment (water depth, water transparency, cloud cover, wind speed), time of day, and behavior (breathing, foraging, milling) on the time-to-detection and detection probability, respectively. Both models indicated a significant interaction between water depth and water transparency, causing an increase in the time-to-detection (β = 0.032; 95% CI = 0.028, 0.037) and a decrease in the probability of detecting manatees (α = -0.65; 95% CI = -1.3, -0.007), which was calculated to be 0.62 (95% CI = 0.23, 0.94). Due to the similarities between the lake and in situ habitats, the results of this study could be used to design in situ UAV survey protocols for Amazonian manatees or other difficult-to-detect freshwater aquatic mammals and to monitor ex situ animals pre-and post-release, which should ultimately contribute to a better understanding of their spatial ecology and facilitate data-driven conservation efforts
Note on the first modern record of a southern elephant seal (Mirounga leonina Linnaeus, 1758) in Los Ríos Region, southern Chile
No full textDrone survey provides preliminary insights into the biological aspects of Bryde’s whales in southeastern Brazil
No full textContributions of bioacoustics to the scientific knowledge of marine mammals in Latin America
No full textWe review and document scientific publications on marine mammal bioacoustics in Latin America between 1971 and 2021, showing eraly scarcity and an increase through time. Marine bioacoustic studies how marine fauna produce and receive sounds hat facilitate their life functions. Bioacoustics explores the biology and ecology of marine mammals, difficult or impossible to carry out using oly traditional methods. From the first published study on the free-living common bottlenose dolphin in the Gulf of Mexico in 1953, acoustic studies on marine mammals have increased; most of its growth occurred in the 2000s. The objective of this study was to document the history and development of marine mammal bioacoustics in Latin America. We conducted a systematic search of scientific peer-reviewed literature on the Web of Science from 1971 to 2021, using keywords involving 18 acoustic and 16 marine mammal terms. We reported the countries where studies were carried out, the focal species, and the research topics. The oldest paper found was published in Chile in 1971. The 2010s yielded the most publications (n = 10), compared to the 1970s (n = 4), 1980s (n = 8), 1990s (n = 12), and the 2000s (n = 49). The publication rate increase between 1971 and 2021 is likely due to the increased development and use of affordable autonomous recording devices. The countries with most publications were Brazil (n = 60), Mexico (n = 46), and Ecuador (n = 29). Those with the least studies were in the Caribbean region. The most studied species were the humpback whale (Megaptera novaeangliae) (n = 46), the sperm whale (Physeter macrocephalus) (n = 43), and the bottlenose dolphin (Tursiops truncatus) (n = 40). These species are highly vocal, widely distributed, and accessible in several habitats, facilitating their study. The most analyzed research topics were inter- and intraspecific differences in vocalizations (n = 104), acoustic signal descriptions (n = 74), and association of acoustic signals and behavior (n = 59). The use of bioacoustics in abundance, distribution, habitat use, and anthropogenic effects was scant in the list of publications reviewed for this study, but these topics are predicted to be pursued more often by researchers in the future as they are needed to establish mitigation policies for the species and their habitat conservation
The Amazon River dolphin, Inia geoffrensis: What have we learned in the last two decades of research?
No full textIn the last decades, knowledge about the biology of the Amazon river dolphin Inia geoffrensis has increased considerably. Accordingly, we present a review of the published literature on this river dolphin, with a focus on topics with the most advancements and those that are important to the species conservation. We also present new information, including emerging knowledge on the other species of Inia. We summarize the current knowledge of the biology of Inia, covering aspects of taxonomy, distribution, life history and reproduction, genetics, anatomy and physiology, health, behavior, ecology, demographic parameters, and population trends. We also highlight the main anthropogenic threats affecting the species and the resulting conservation efforts
