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See detailOccurrence of bottlenose dolphins (Tursiops truncatus) in the Río Negro Estuary, Argentina, and their mid-distance movements along the Northeast Patagonian coast
Failla, Mauricio; Seijas, Veronica; Vermeulen, Els ULg

in Latin American Journal of Aquatic Mammals (in press)

A systematic study on the presence of bottlenose dolphins (Tursiops truncatus) in the Río Negro Estuary (RNE), Patagonia Argentina, was carried out between the months March – July from 2008 to 2011. Data ... [more ▼]

A systematic study on the presence of bottlenose dolphins (Tursiops truncatus) in the Río Negro Estuary (RNE), Patagonia Argentina, was carried out between the months March – July from 2008 to 2011. Data on the dolphin’s activity patterns were gathered via an Ad Libitum focal group sampling mode accompanying dorsal fin images taken for identification and re-identification of individuals. A total effort of 188 h resulted in 58 h of positive observation of 124 dolphin groups (sightings per unit effort (SPUE) = 0.66 groups/h). Data analysis showed two main activity states for the observed groups, travelling (65%) and foraging (26%). The remaining 9% of the groups were involved in other activity states. The photo-identification effort, which started opportunistically in 2006, resulted in a catalogue of 21 individual dolphins, with a total mean re-identification rate of 9 days (max = 24 days). When comparing these pictures to the existing catalogue of Bahía San Antonio (approximately 200 km west from the study area) dorsal fins of 20 individuals could be positively matched and most (n = 17) could be subsequently re-identified in both areas, indicating their long distance movements along the North Patagonian coast during the austral autumn months. This season coincides with the lowest amount of feeding activity observed in Bahía San Antonio. This study suggests that bottlenose dolphins enter RNE, mainly during autumn, to forage. It appears that the search for food resources may be the trigger for their movement patterns along the North Patagonian coast during this season, at least for certain individuals. More research is needed to accurately confirm this hypothesis. [less ▲]

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See detailAN IDENTIFICATION STUDY ON BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS) IN NORTHEAST PATAGONIA, ARGENTINA
Vermeulen, Els ULg; Cammareri, Alejandro; Failla, Mauricio et al

Poster (2008, October 13)

In Argentina, bottlenose dolphin (Tursiops truncatus) sightings decreased notably since the late 80s in regions where it used to be frequent to observe them. Nowadays, Northeast Patagonia is one of the ... [more ▼]

In Argentina, bottlenose dolphin (Tursiops truncatus) sightings decreased notably since the late 80s in regions where it used to be frequent to observe them. Nowadays, Northeast Patagonia is one of the few regions where they still can be seen frequently, although local increasing human activities result in increasing need for information. In general, photo-identification has been established as a helpful tool in cetacean research. However, only few studies have applied this method to bottlenose dolphins in Argentina. This study is therefore aimed to obtain basic information concerning bottlenose dolphins through their identification, this way contributing to their conservation. Land-based observations were made in the northern Gulf of San Matías, Patagonia, Argentina, from August 2006 up to June 2008. Over 15.000 digital pictures of dorsal fins were analysed using the computer assisted identification systems FinEx and FinMatch. Dolphins re-identified during all four seasons in one year were defined as residents. The degree of residency was further estimated by the re-identification frequency (RF); non-resident (RF=1-3) - occasional (RF=4-7) - frequent (RF=8-11) - common (RF¿12). In total, 221 surveys were conducted with an average observation effort of 3.2h per survey, resulting in a total observation effort of 915h of which 124h were spent with 182 dolphin groups. A total of 50 dolphins were identified of which the vast majority (82%) was photographed only in the Natural Protected Area Bahía San Antonio (NPABSA), due to the higher observation effort in this region. Nevertheless, 12% of the catalogued dolphins could be photographed in both NPABSA and the Río Negro estuary, indicating that their home-range might include at least the whole northern region of the Gulf San Matias. Dolphins could be re-identified up to 13 days with 54% showing a degree of residency for NPABSA. This study shows the first data concerning bottlenose dolphins in Northeast Patagonia, but further investigation is highly necessary to improve their conservation. Therefore, the obtained photo-identification catalogue from the presented study is meant to serve as a primary tool for progressing research concerning this species in Argentina. [less ▲]

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See detailA photo-identification catalogue of bottlenose dolphins (Tursiops truncatus) in Northeast Patagonia, Argentina: A tool for the conservation of the species
Vermeulen, Els ULg; Cammareri, Alejandro; Failla, Mauricio

in Report to the International Whaling Commission (2008)

A photo-identification study of bottlenose dolphins (Tursiops truncatus) was performed in the northern Gulf of San Matías, Patagonia Argentina, during the period 2006-2008. In total, 199 surveys were ... [more ▼]

A photo-identification study of bottlenose dolphins (Tursiops truncatus) was performed in the northern Gulf of San Matías, Patagonia Argentina, during the period 2006-2008. In total, 199 surveys were conducted with an average observation effort of 4.2h (SD=1.5) per survey. These surveys resulted in a total observation effort of 824.7h of which 105.7h was spend with 158 dolphin groups. Over 12,500 pictures were analysed using the automatic identification systems FinEx and FinMatch (EuroPhlukes Initiative, Leiden University, The Netherlands), resulting in the first identification catalogue of 47 dolphins for the North Patagonian region. The catalogued dolphins were re-identified up to 13 days with 57% (n=47) showing a degree of residency for the Natural Protected Area Bahía de San Antonio (NPABSA; resighting frequency (RF)≥4). At least 6 dolphins, including one mother with her calf, were additionally re-identified inside the estuary of the river ‘Rio Negro’, 250km east, indicating that their home-range includes at least the whole northern region of the Gulf of San Matias. Data suggest that it concerns a stable but yet unknown population of bottlenose dolphins with a high touristic potential and an urgent need of conservation measurements. The obtained photo-identification catalogue is meant to serve as a tool for the conservation of the species and the realization environmental education projects in the region. [less ▲]

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See detailHistorical records of southern right whales (Eubalaena australis) of the province Río Negro, North Patagonia, Argentina (1991-2008)
Failla, Mauricio; Vermeulen, Els ULg; Cammareri, Alejandro

in Report to the International Whaling Commission (2008)

The increase of the southern right whale (SRW Eubalaena australis) population might rise questions about the reoccupation of previous sites. This report is a compilation of historical records of SRWs ... [more ▼]

The increase of the southern right whale (SRW Eubalaena australis) population might rise questions about the reoccupation of previous sites. This report is a compilation of historical records of SRWs along the coast of the Río Negro province, Northeast Patagonia, to evaluate the tendency of their occurrence in the area over the past decade. A total of 308 records (425 whales) were collected over distinct coastal regions in Northeast Patagonia. The majority of sightings were concentrated between the months July-October with a peak in August-September as was observed similarly in South Brazil, Uruguay and central Patagonia. Groups consisted out of 2 individuals on average whereas mother and calf pairs could be observed in only 11% of the sightings. There was a general increase in sightings over the subsequent years possibly explained by a cause-response relation of increasing sightings and increasing effort. The information presented in this report could suggest a similar hypothesis of reoccupation in the province of Río Negro, Argentina, as was suggested to be occurring along the southeastern coast of Brazil, Uruguay and the Santa Cruz province of Argentina. Data are too preliminary however, to determine the importance of this area for the reproduction and/or migration of this species. Nevertheless, the presented data completes an evolving database of the presence of SRWs along the whole Patagonian coast as was recommended by the International Whaling Commission in 2001. More data and systematic effort is needed to obtain the information on the ecology of SRWs in the Río Negro province, needed for the implementation of conservation measurements in the waters of the provincial jurisdiction, specially in the touristic area of the Natural Protected Area Bahía San Antonio. [less ▲]

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See detailSIGHTING FREQUENCY AND PHOTO-IDENTIFICATION OF BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS) ALONG THE COAST OF BAHÍA SAN ANTONIO, PATAGONIA, ARGENTINA
Holsbeek, Ludo; Cammareri, Alejandro; Failla, Mauricio et al

Poster (2008, March 10)

The sighting frequency (SF), site fidelity, home-range and group composition of bottlenose dolphins (Tursiops truncatus) were assessed during a photo-identification study in 2006-2007. This study aims to ... [more ▼]

The sighting frequency (SF), site fidelity, home-range and group composition of bottlenose dolphins (Tursiops truncatus) were assessed during a photo-identification study in 2006-2007. This study aims to provide first data on this unknown austral bottlenose dolphin population to answer to their increasing conservation needs. Data and pictures were collected during 132 surveys with an average observation effort of 2.8h (SD=1.6) per survey. All clear pictures were analysed using the automatic identification systems FinEx and FinMatch (EuroPhlukes Initiative). The SF was obtained dividing the number of sightings by the amount of effort. Site-fidelity was estimated using the Capture Mark Recapture method and the degree of residency by the re-identification frequency following Culloch (2004). In total, 377.4h were spent searching for bottlenose dolphins of which 57.3h were spent in the presence of 126 dolphin groups divided in 105 sightings. The SF was 0.28/h with and average duration of 43.2min/sighting (SD=0.76). A total of 43 dolphins were classified into an identification catalogue. These recognizable dolphins were re-identified up to 10 days with 44% (n=43) showing a degree of residency (resighting frequency (RF)¿4). The average group size was 6.1 (SD=7.9) ranging from one to fifty animals. Group size increased significantly with the presence of calves and with the distance from the coast. Nevertheless, all dolphins were seen in inshore waters ¿20m deep. The most frequent group formation was loose (34.5%), variable (29.8%), disperse (20.2%) and tight (15.5%). At least 6 identified dolphins, including one mother with her calf, were photographed in the mouth of the Rio Negro 250km from the study area indicating that their home-range is far from limited to Bahia de San Antonio. Data indicate that it concerns a resident but yet unknown population of bottlenose dolphins with a high commercial potential and an urgent need of conservation measurements. [less ▲]

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