Latin American Journal of Aquatic Mammals (LAJAM)
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Behavior and habitat use of released rehabilitated Amazonian manatees in Peru
No full textThe Amazonian manatee (Trichechus inunguis) is endangered due to illegal hunting. In Peru, the Centro de Rescate Amazónico (CREA) rehabilitates and releases rescued manatees. Tree 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.
Recurrent sightings of a Southern elephant seal (Mirounga leonina) on the southeast coast of Brazil, 2012 – 2017
No full textWe report four years (2012-2015) of consecutive observations of the same juvenile male Southern elephant seal along the coast Espírito Santo (ES), Brazil, identified based on scars of cookiecutter shark bites. In 2015 three bacteries were isolated from a recent lesion using routine methods of bacterial culture and identification, and a large number of barnacles were seen attached to the fur of other body regions, especially on the pelvic limbs and lower back. We collected 12 barnacles from different body areas, and identified all of them as Eared barnacles (Conchoderma aurita). Additionally, a sample of feces was obtained and analyzed through simple-flotation, revealing helminth eggs compatible with Contracaecum sp
Marine mammal distribution in Ecuador: surveys aboard a ship of opportunity as a means of monitoring relative abundance
No full textFive marine mammal surveys between 2008 and 2011 were conducted aboard the Buque de Investigación Orion (the research vessel for the Oceanographic Institute of the Ecuadorian Navy) within oceanic waters adjacent to mainland Ecuador and the Galápagos Islands. The surveys dedicated extensive time in deep, offshore waters where cetaceans were not densely present. Sightings of 12 species were compared with an earlier survey aboard the B/I Orion in 2001 as well as with a subset of published data from three NOAA STAR (Stenella Abundance Research) surveys between 1999 and 2003. Additionally, a small boat, near-shore survey, was conducted during June 2010 among andnear the Galápagos Islands. Encounter rates ranged annually from 0.012 cetacean/km to 0.027 cetacean/km. The highest encounter rate aboard the B/I Orion took place during the April 2009 survey. In order to compare sightingrates between the B/I Orion and NOAA platforms, the average effective half-strip widths were used to determine encounter rates per area effectively searched. A zonation within the study region was observed between odontocete andbalaenopterid cetaceans as well as between striped (Stenella coeruleoalba) and short-beaked common dolphins (Delphinus delphis). Several methodological aspects of surveys and geographical features that may influence encounter rates and subsequent abundance estimates are discussed. This study demonstrates that vessels of opportunity provide a valuable means of studying open-ocean and coastal distributions of marine mammals. Possible methodological improvements, such as the use of high-power binoculars, that could increase the absolute number of sightings, the efficiency of these opportunistic surveys, and improve the sighting rates of more evasive species are discussed
Observation of a potential mating herd in Amazonian manatee
No full textWe report what is believed to be the first description of a mating herd among Amazonian manatee
LAJAM Editorial 12(1-2) 2017: Our State of the Union
No full textPresents regular volume 12 issues 1 and 2 (2017
A review on the distribution, abundance, residency, survival and population structure of coastal bottlenose dolphins in Argentina
No full textAlthough bottlenose dolphins Tursiops truncatus are among the most common delphinid species, global population trends remain poorly understood. To improve the knowledge of the species in the Southwest Atlantic Ocean, thispaper reviews all available data related to the distribution and occurrence, abundance, residency and ranging patterns, group size and composition, survival and reproduction and population structure of the coastal bottlenose dolphin in Argentina. Most information proved to be scattered in time and space. Based on the available data, total abundance of coastal bottlenose dolphins in Argentina appears to be low. Data show sightings decreased notably since the 1990s in the northern province of Buenos Aires and the province of Chubut, with the species having disappeared completely from the former region. Data also indicated that two genetically and morphologically distinct coastal populations occur in Argentinean coastal waters, with a sympatric distribution in the provinces of Río Negro and Chubut. One is an isolated ‘Evolutionary Signifcant Unit’ within the larger Southwest Atlantic, whereas the other population appears to be genetically related to the Southwest Atlantic offshore ecotype. In the absence of more substantial data, the present information is pertinent to our scientifc knowledge of the species in the country, collating all published information as well as information from grey literature and previously unpublished data. However, the available information appears to remain insufcient to explain the apparent decline in sightings and to assess the remaining abundance nationwide accurately. Therefore, we strongly recommend increased research efforts for an in-depth assessment of the species’ population status in Argentina
Encounter rates of the Bolivian river dolphin (Inia boliviensis) in northeastern Bolivia
No full textThis study provides information on seasonal distribution patterns for river dolphins in Bolivia
Recent strandings of sperm whale, Physeter macrocephalus, in southern Peru
No full textAuthor reports on a stranding of a female sperm whale in the Peruvian southern coast and review other similar events
Report of the Working Group on the Biology and Ecology of Tursiops truncatus in the Southwest Atlantic Ocean
No full textWe review information on the biology and ecology of common bottlenose dolphin (Tursiops truncatus) in the Southwest Atlantic Ocean (SWAO) with emphasis on growth, feeding ecology, epizootics and parasites, predation and pathologies
Occurrence of bottlenose dolphins (Tursiops truncatus) in the Río Negro Estuary, Argentina, and their mid-distance movements along the northeastern Patagonian coast
No full textA systematic study was carried out on bottlenose dolphins (Tursiops truncatus) in the Río Negro Estuary (RNE), Patagonia, Argentina, to analyze their occurrence and activity patterns in this region. The photo-identification data of this study was further compared to data from an adjacent region to gain information on the animals' movements along the northeastern Patagonian coast. Information was gathered through land-based observations between the months of March and July of 2008 up to 2011. Data on dolphin activity patterns were collected via an ad libitum focal-group sampling mode. At the same time, dorsal fin images were obtained from as many dolphins as possible for identification and subsequent re-identification of individuals. Total effort equaled 188h, resulting in 58h of observation of 124 dolphin groups [sightings per unit effort (SPUE) = 0.66 group/h]. Most of the groups observed contained between one and five individuals, and two main activity states could be determined, namely traveling (65%) and foraging (26%). The photo-identification effort, which started opportunistically in 2006, resulted in a catalogue of 17 individual dolphins, with a total mean re-identification rate of nine days (max. = 24 days). When comparing these pictures to the existing catalogue of Bahía San Antonio (BSA; approximately 200km west from the study area) dorsal fins of 15 individuals could be matched and most (n = 12) could be subsequently re-identified in both areas, indicating their long distance movements along the northeastern Patagonian coast during the austral autumn months. This season coincides with the lowest dolphin abundance and feeding activity in BSA. This study indicates that bottlenose dolphins enter the RNE to forage at least during autumn. It further suggests that the search for food resources is the main trigger for their movement patterns along the northeastern Patagonian coast during this season, at least for certain individuals. More research is needed to accurately confirm these hypotheses