Latin American Journal of Aquatic Mammals (LAJAM)
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Sperm whale, Physeter macrocephalus, harassment by killer whales, Orcinus orca, in the western South Atlantic Ocean
No full textSpatial distribution and abundance of baleen and sperm whales in the Peruvian sea: a historical review
No full textHistorical accounts of large whales in Peruvian waters existed before modern commercial whaling. Research on baleen and sperm (Physeter macrocephalus) whales was intense during whaling, thus producing essential knowledge on these species. The populations of large whales have declined considerably with whaling pressure since 1925 in Peruvian waters. After the whaling moratorium in 1985, research on these species decreased, and a considerable gap in knowledge exists until nowadays. This review aims to conduct a historical analysis of the spatial distribution and abundance of baleen and sperm whales in the waters of Peru. During whaling, sperm whale distribution and abundance received most of the research effort as this species was the most important target of the whaling fleet. Also, blue (Balaenoptera musculus) and Bryde’s whale (B. edeni brydei) were considered abundant in Peru. Changes in their distribution and abundance were evaluated mainly based on captures or climatic events. Following the cessation of whaling, sightings of these species were restricted to occasional surveys, limiting the assessment of possible current changes in their distribution and abundance, as well as the updating of existing information. Humpback whales (Megaptera novaeangliae) were considered overexploited at the beginning of commercial whaling. After the moratorium, this species population started to grow, expanding its distribution along the northern coast. Currently, the humpback whale is the most studied species due to the onset of whale-watching activities in 2009. This allowed us to update and increase the knowledge about its distribution and abundance in northern Peru. The findings of this study point at a need to considerably increase the research effort on large whales, particularly surveys to estimate population sizes of the species inhabiting the waters of Peru
Professor Júlio Ernesto Baumgarten: (1965 – 2022)
No full textThis is an obituary for Professor Júlio Ernesto Baumgarten
Carcass non-recovery rate of franciscana dolphin (Pontoporia blainvillei), calibrated with a drift mark-recapture study at FMA Ia, Brazil
No full textThe franciscana dolphin (Pontoporia blainvillei) is one of the smallest dolphins globally and the most threatened in the Southwest Atlantic Ocean. Beach monitoring helps to investigate cetacean strandings within their distributions and assess impacts that cause mortality. Using drifters in mark-recapture studies helps to estimate recovery rates when carcasses are unavailable. The study aims to estimate the non-recovery rate of franciscana carcasses from FMA Ia by comparing the spatial distribution between carcasses and drifters along the coast; correlating the influence of cold fronts with the recovery rate of drifters; estimating the non-recovery rate of carcasses according to the drifters’ results and the meteorological profile in the pre-stranding period; characterizing the death diagnostic with temporal distribution of franciscanas by considering the stranding index and the carcass non-recovery rates. We repeated the release of 54 drifters in two campaigns close to the coast within the range of franciscana dolphins, where beaches are monitored daily, in the north region of Espírito Santo state, Brazil. The carcass stranding hotspots (21%) and drifters (18%) were 10 km apart. Cold fronts significantly increase the number of strandings. Considering the incidence of cold fronts in the pre-stranding period and linear regression from drifters, the median carcass recovery rate is 0.26, 95% IC [0.22 - 0.29], which means that for each stranding, the carcass non-recovery rate varies from 0.78 to 0.71. The range between 265 to 350 estimates the total of carcasses from 77 strandings observed from 2003 to 2021. The record year of strandings was 2014 (n = 14). About 52% of records occurred in summer, and January is the month with the highest occurrence of strandings. Of the conclusive diagnoses (n = 43), around 77% (n = 33) were attributed to incidental capture in gillnets. Estimating the number of carcasses based on stranding records is essential for population viability analyses and conservation purposes, especially considering small and isolated populations as in the present study. To prevent local extinction, a solution to avoid incidental capture, especially along summers, must be addressed quickly
River dolphins (Inia geoffrensis and Sotalia fluviatilis) in the Peruvian Amazon: habitat preferences and feeding behavior
No full textTo estimate river dolphin habitat preference through density, as well as which habitats were preferred for feeding in the Pacaya- Samiria National Reserve, surveys were conducted during the high- to low-water season transition, from 2016 to 2018, in the channels, lakes, and confluences of the Samiria River. Both the Amazon river dolphin and tucuxi dolphin showed a preference for the confluences. The wide channel (Amazon: 24.8 dolphins/ km2, tucuxi: 7.6 dolphins/km2) and narrow channel (Amazon: 73.0 dolphins/km2; tucuxi: 6.0 dolphins/km2) also had high dolphin densities, especially for the Amazon river dolphins. In contrast with previous studies, the lakes had the lowest densities of dolphins for both species. High proportions of feeding behavior were observed in the confluence and wide channel habitats. The potentially larger presence of fish in these two habitats is likely the primary reason for the high dolphin densities. The high dolphin densities in the narrow channel, on the other hand, were associated with a low proportion of feeding behavior. Therefore, there are likely separate environmental factors attracting the dolphins, although additional data will be required to determine these factors. The results of this study will continue to help identify potential conservation and management actions by contributing to a better understanding of the ecology of river dolphins and their dependence on various habitats in one of the world’s largest protected flooded forests.
Two cases of malformations in bottlenose dolphins Tursiops truncatus (Montagu, 1821) in Aragua, Venezuela
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Hunting and hunters of the Amazonian manatee in a Brazilian protected area
No full textThe Amazonian manatee has been hunted since antiquity and is part of local culture and tradition. Although protected by law, manatees continue to be hunted for food and trade. In most regions where the species occurs there are no reliable data on current hunting pressure. In addition, difficulty in determining its abundance prevents the definition of the species’ conservation status. Through an interdisciplinary research approach bringing together quantitative and qualitative data in the context of a trusting relationship with our local community partners, we assess current hunter profiles and associated hunting data. Hunting manatees in this region is linked to strong family traditions. The belief that ‘manatees are not for everyone’ as well as the considerable value given to their meat, results in hunters being recognized and admired. The manatees of Amanã are vulnerable to hunting year-round, throughout their route of in-reserve seasonal migration, and probably throughout other migration routes in the region. We conclude that if conservation is to be effective, the professionals, policies, and practices involved must consider local traditions related to manatee consumption. Likewise, the difficulty for local communities to fully grasp the threat of extinction to the species poses a significant challenge to conservation efforts. The information on manatee hunting in the Amanã Sustainable Development Reserve generated by this work is unprecedented for the species and has served as the basis for monitoring and establishing conservation measures appropriate to the local reality
