Latin American Journal of Aquatic Mammals (LAJAM)
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Incidence of a solitary bottlenose dolphin, Tursiops truncatus, and interactions with spinner dolphins, Stenella longirostris, in the Fernando de Noronha Archipelago, Brazil
No full textThe Projeto Golfinho Rotador (PGR, Spinner Dolphin Project) has systematically monitored the distribution, ecology, and behavior of cetaceans in the Fernando de Noronha Archipelago (FNA) since 1990. During this period, the presence of spinner dolphins (Stenella longisrostris) was recorded in 93% of the days of the year, and occasionally another nine species of cetaceans. As of November 2021, the presence of a solitary bottlenose dolphin (Tursiops truncatus), known as Kai, was observed in the FNA. This work aims to describe the frequent presence of the solitary bottlenose dolphin in the FNA, as well as the interactions between that individual and the spinner dolphins. The records were made from two land-based platforms on the main island, and by collecting information and images from collaborators, such as sailors and divers. From 10 November 2021 to 23 July 2022, between the first and last sightings, in 223 days of study and 2,210.22 h of sampling effort, 49 sightings of the bottlenose dolphin were recorded. It was an adult, offshore ecotype, of unidentified sex and apparently healthy. On days when Kai was sighted, the spinner dolphins stayed an average of 5.84 h in the area (SD ± 3.02), while on days without sightings the average permanence was 6.20 h (SD ± 2.65). There was no effect of the presence of Kai on the permanence of the spinner dolphins (Mann-Whitney, U = 1042; p = 0.678), with a predominance of neutral interactions. According to the habituation stages currently adopted, Kai was in stage two, in which it was already known by the local population, followed some boats, but still kept its distance from humans. The existence of legislation to protect cetaceans and the action of the PGR in the community may have helped with the non-progression of the habituation stage
Occurrence, abundance and some ecological aspects of the offshore bottlenose dolphin off Ecuador’s central coast
No full textThe presence of the offshore bottlenose dolphin (Tursiops truncatus) is poorly understood for most of the southeast Pacific Ocean. Its wide distribution, low density, and lack of understanding of its ecology make the species unpredictable to observe and difficult to study compared to the coastal ecotype. We assessed the occurrence of offshore bottlenose dolphins off the central coast of Ecuador (01°36’ S, 80°58’ W) using information taken from 2001 to 2022. Data were collected by two research groups based 80 km apart, one in Puerto López (north) and the other in Salinas (south). A total of 48 dolphin groups were documented, 22 at Puerto López and 26 at Salinas. In Puerto López, 163 dolphins were individually identified, of which 70 intra-annual sightings and 102 inter-annual sightings were found. Inter-annual resightings at Puerto López corresponded to 55 individuals (33.7%) recorded between two and 17 years (mean = 5.82 years, SD = 5.1). In Salinas, 58 dolphins were identified, without intra-annual resightings and only two inter-annual sightings. Only one individual was recorded in both areas. Two site fidelity indexes were calculated, Occurrence (Oi) and Permanence (Pi), resulting in 11 and 13.7 times higher respectively, in Puerto López. The abundance at Puerto López, 163 animals (95% CI, 120 - 203) in 2021-2022, was estimated with a closed population model. The prevalence of scars associated with previous encounters with fishing gear was 43.6%, commensal barnacle (Xenobalanus globicipitis) infestation 42.3%, predation 3.6%, and dermal nodules 0.61%. Our findings suggest both site fidelity and some degree of population structure, but additional monitoring and genetic studies are needed to clarify these aspects. Nevertheless, this study provides information on key aspects necessary for developing conservation strategies for offshore bottlenose dolphins
Aquatic mammal fossils in Latin America – a review of records, advances and challenges in research in the last 30 years
No full textRecords of aquatic mammal fossils (e.g. cetaceans, pinnipeds, sirenians, mustelids, and desmostylians) from Latin America (Mexico to Tierra del Fuego, including Antartica) span since the mid-1800s. Aquatic mammal fossils received little attention from the scientific community, with most of the first studies conducted by Northern Hemisphere researchers. Over the last 30 years, paleontological research in Latin America has increased considerably, with descriptions of several new species and revisions of published original records. The Latin American fossil record of marine mammals spans from the Eocene to the Pleistocene, with formations and specimens of global significance. All three main groups of cetaceans are represented in the continent (Archaeoceti, Mysticeti, and Odontoceti). Pinnipedia are represented by the families Otariidae and Phocidae, with records starting in the Middle Miocene. Both living families of Sirenia (Trichechidae and Dugongidae) are recorded. While less common, but still relevant, records of desmostylians and mustelids are known from Oligocene and Miocene deposits. This review provides a summary of the aquatic mammals known to date, with a special focus on the advances and developments of the last 30 years, since Cozzuol’s (1996) review of the South American fossil record. An up-to-date complete list of species based on the literature and unpublished data is also provided. The study also provides future directions for paleontological research in Latin America, and discusses the challenges and opportunities in the field, including the emergence of a strong new generation of Latin American researchers, many of whom are women
Advances in the knowledge of the biology and conservation of the Amazonian manatee (Trichechus inunguis)
No full textThe last relevant work that reviewed the biological and conservation aspects of the Amazonian manatee (Trichechus inunguis) was published almost 30 years ago. In these three decades, scientific knowledge about the species has advanced substantially. This review article updates knowledge about the various biological and conservation aspects of Amazonian manatee, summarizing the information present in the literature. Topics such as morphology, habitat, distribution, population aspects, food and feedings habits, reproduction, behavior, health, threats, status, and conservation efforts were addressed. The main actions already carried out, as well as the future strategies needed for the conservation of the Amazonian manatee, are also highlighted
Review of threats and implementation of the Regional Action Plan for the Conservation of Marine Mammals in the Wider Caribbean Region
No full textThe Action Plan for the Conservation of Marine Mammals in the Wider Caribbean Region (MMAP) was adopted in 2008 by Contracting Parties under the Protocol concerning Specially Protected Areas and Wildlife (SPAW) of the Cartagena Convention, administered by the United Nations Environment Programme (UN Environment). After more than a decade of MMAP-related programmatic work under SPAW, this paper presents a synthesis of major threats to marine mammals in the Region and an assessment of progress achieved by the 17 Contracting Parties to the SPAW Protocol toward achieving implementation of the MMAP and based upon a scientific and technical analysis conducted in 2020. The country assessment focused on 11 threat categories (indicators), along with two additional indicators relating to country legislation and national action plans. As part of this scientific and technical analysis, surveys were sent to SPAW Contracting Party focal points and individual interviews were conducted with key regional organizations and experts. For every SPAW Contracting Party, each indicator was assigned a relative level of its current intensity (Low, Moderate, High, or Unknown). A similar scheme was utilized to represent each country’s response to that threat. The results highlighted those threats that were of concern for several countries and hence may be considered a management priority at the regional scale. In terms of threat mitigation, these priorities are: interaction between marine mammals and fisheries, pollution, and acoustic disturbance. Regarding needs, the development of national marine mammal action plans, as well as the implementation of research and monitoring programmes dedicated to marine mammals, should be considered a priority. Finally, two threats were found to be of high priority for knowledge enhancement: acoustic disturbance and vessel strikes. It is important to note that this review was not intended to single out insufficient country effort, but rather assist Wider Caribbean countries to identify threats and/or issue areas which would benefit from attention
First record of gillnet entanglement of a common minke whale calf (Balaenoptera acutorostrata, Lacépède, 1804) in Haiti, Greater Antilles, with a note on the local and regional fishing techniques
No full textOverview of Balaenoptera whales strandings in Southern Brazil from 1993 to 2018
No full textThe ecology and distribution of most baleen whales are poorly known in Brazilian waters, despite the history of whaling and the recent increase in the research effort. Although stranding data presents some caveats, it is useful to understand patterns of distribution and occurrence and to detect population trends. In this scenario, data from 25 years of a monitoring marine mammal stranding program were used to evaluate the composition and spatial-temporal patterns of Balaenoptera whales in southern Brazil. A stretch of 270 km on the coast of Rio Grande do Sul State (from 29°20’S to 31°21’S) was surveyed year-round between 1993 and 2018. Whales were identified, measured and sex determined whenever possible. Molecular identification through mtDNA analysis was obtained for 22 individuals and confirmed field identification in 17 cases. Forty-eight whales of four species were recorded: common minke whale B. acutorostrata n = 27, Antarctic minke whale B. bonaerensis n = 1, Bryde’s whale B. brydei n = 13, fin whale B. physalus n = 1. In addition, six whales were not identified at species level due to advanced decomposition. The larger number of strandings of common minke and Bryde’s whales may be related to their greater abundance and/or more coastal distribution. Both species were recorded year-round, but strandings of common minke and Bryde’s whales occurred mostly during winter/spring (77.77%) and spring/summer (66.66%), respectively. Although Bryde’s whales appear to remain in southern Brazilian waters during the entire year, the results suggest the existence of seasonal inshore-offshore movements. Moreover, the greater number of strandings of juveniles of common minke whales compared to adults (ratio 1.86:1) and their occurrence in different seasons suggest that some immature individuals may not leave this region, as previously pointed out by other studies. This long-term survey brings new evidence of the importance of this region in the Southwestern Atlantic Ocean for some Balaenoptera species
Seeing in the dark: A review of the use of side-scan sonar to detect and study manatees, with an emphasis on Latin America
No full textManatees are aquatic mammals that live in a variety of environments. Many of those shallow water environments have murky water, making detection using traditional visual surveys very challenging. Side-scan sonar was first proposed as a tool to detect and study manatees in these complicated habitats in 2005. Here, we summarize the use of this tool from 2005 to 2022 by searching the available literature. Our literature search revealed that this tool is being widely used in more than 20 locations and over 15 countries. All three manatee species are being studied with side-scan sonar. It is most useful in murky freshwater habitats that are not too deep or open (e.g., large lagoons or lakes), where visual surveys are not effective. Most studies used side-scan sonar in combination with other methodologies such as passive acoustics and indirect evidence. Work is still needed to standardize the use of this technique so that image interpretation can be reliable, and results can be compared between studies. However, most studies indicated that this tool is essential in murky water habitats and provides one of the best ways to detect and study manatees.