Behavioural response of southern right whales (Eubalaena australis) to anthropogenic approaches in Bahía San Antonio, Río Negro Argentina

The behavioural response of southern right whales (SRWs) to human approaches was studied in Bahia San Antonio, Río Negro Argentina, to obtain essential information for the evaluation of a recent authorized whale-based tourism and the implementation of accurate regulations and conservation measurements. A total of 50 SRW groups were approached with a small zodiac during the whale-seasons (June-October) of 2008 and 2009, accounting for a total of 39h of behavioural observations. The approaches occurred in a slow and controlled way up to a minimum distance of 100m. A focal animal observation (instantaneous point sample) was used to record three mutual exclusive behavioural states: rest, travel and socializing and/or aerial activity. Groups (chosen ad random) consisted out of solitary animals (0.52), Surface Active Groups (SAG; 0.32) and non-SAGs (0.13). Nevertheless, because of the low amount of data, up to now all behavioural responses were analysed regardless group composition. Results indicated that whales continued travelling during an approach, but doubled their time resting after an approach had finished (22% → 40%) and decreased drastically their time socializing or aerially active (21% → 2%). Although the probability that a whale remained in a social/aerially active behaviour when affected by anthropogenic approaches decreased notably (-22%), no significant effect could be found up to now (Z-test for 2 proportions, p>0.05), probably due to the relative small dataset. Nevertheless, the apparent change in SRW social behaviour requires urgently more detailed information to implement conservation strategies regulating adequately the commercial whale-based tourism in the area

Variation in external morphology of resident bottlenose dolphins in Bahía San Antonio, Patagonia, Argentina

peer reviewedA photo-identification study carried out in Bahía San Antonio (Patagonia Argentina) showed a variation in external morphology among year-round resident bottlenose dolphins. Out of 63 individually identified bottlenose dolphins, 15 were considered year-round residents of which three show variations in external morphology: they have a more falcate dorsal fin, darker coloration and shorter beak, physical characteristics described for the regional form of bottlenose dolphins present in the more southern province Chubut. The three morphologic distinct individuals, with one associated calf, could be re-identified in the study area up to 10 times over all the different seasons and up to now, no other bottlenose dolphins with similar characteristics could be observed in the area. On all occasions, they were re-identified in close occasions with each other and on 8 occasions in close association with other identified individuals. So far it was believed that the two regional forms of bottlenose dolphins present in Argentina were isolated. This communication is meant to document the residency and interaction of both regional forms in the same area

Emissivity rules: Principles of infrared whale detection revisited

Thermographic (infrared/IR) imaging has been demonstrated repeatedly to reliably capture whale cues at mitigation relevant distances, including at night when visual observations are essentially futile. IR performance may however be subject to environmental conditions as well as the observed species, as a cue’s IR perceptibility requires a finite difference between cue and oceanic radiances, raising the question of to what degree this method is applicable globally. Particularly for tropical and equatorial climates, a general concern exists that warm ocean water would reduce the contrast between cue and oceanic radiance because of a lesser temperature difference between the two. Contrary to the underlying assumption that thermal contrast between cue and ocean governs the difference in radiance, our quantitative statistical analysis of 1900 cues demonstrates that the difference between oceanic radiance and both blow or body radiances is, to first order, constant, i.e. independent of the oceanic radiance, an observations also reported recently by Horton et al. (2017). Our paper explores the extent to which this correlation is subject to global ambient radiances, angular emissivity and the aspect at which the ocean background and the cue are viewed respectively, i.e., glancing with low angular emissivity for the near horizontal ocean surface versus near perpendicular with high angular emissivity for body parts and blow droplet facets. Notwithstanding the linear correlation between cue and ambient radiance, residual inter-cue variations in radiance suggest individual dependencies and thermodynamic processes modify cue radiance, aspects to be discussed with regard to their impact on the cue’s IR perceptibility

Scaling the laws of thermal imaging-based whale detection

Author Posting. © American Meteorological Society, 2020. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of the Atmospheric and Oceanic Technology 37(5), (2020): 807-824, doi:10.1175/JTECH-D-19-0054.1.Marine mammals are under growing pressure as anthropogenic use of the ocean increases. Ship strikes of large whales and loud underwater sound sources including air guns for marine geophysical prospecting and naval midfrequency sonar are criticized for their possible negative effects on marine mammals. Competent authorities regularly require the implementation of mitigation measures, including vessel speed reductions or shutdown of acoustic sources if marine mammals are sighted in sensitive areas or in predefined exclusion zones around a vessel. To ensure successful mitigation, reliable at-sea detection of animals is crucial. To date, ship-based marine mammal observers are the most commonly implemented detection method; however, thermal (IR) imaging–based automatic detection systems have been used in recent years. This study evaluates thermal imaging–based automatic whale detection technology for its use across different oceans. The performance of this technology is characterized with respect to environmental conditions, and an automatic detection algorithm for whale blows is presented. The technology can detect whales in polar, temperate, and subtropical ocean regimes over distances of up to several kilometers and outperforms marine mammal observers in the number of whales detected. These results show that thermal imaging technology can be used to assist in providing protection for marine mammals against ship strike and acoustic impact across the world’s oceans.This work was funded by the Office of Naval Research (ONR) under Award N000141310856, by the Environmental Studies Research Fund (ESRF; esrfunds.org) under Award 2014-03S and by the Alfred-Wegener-Institute Helmholtz Zentrum für Polar- und Meeresforschung. DPZ and OB declare competing financial interests: 1) Patent US8941728B2, DE102011114084B4: A method for automatic real-time marine mammal detection. The patent describes the ideas basic to the automatic whale detection software as used to acquire and process the data presented in this paper. 2) Licensing of the Tashtego automatic whale detection software to the manufacturer of IR sensor. The authors confirm that these competing financial interests did not alter their adherence good scientific practice. We thank P. Abgrall, J. Coffey, K. Keats, B. Mactavish, V. Moulton, and S. Penney-Belbin for data collection or IR image review. We thank S. Besaw, J. Christian, A. Coombs, P. Coombs, W. Costello, T. Elliott, E. Evans, I. Goudie, C. Jones, K. Knowles, R. Martin, A. Murphy, D. and J. Shepherd; and the staffs at the Irish Loop Express, the Myrick Wireless Interpretive Centre, the Mistaken Point Ecological Reserve, and the lighthouse keepers for logistical assistance at our remote field site. We thank D. Boutilier and B. McDonald (DFO) for assisting us in obtaining license to occupy permits for Cape Race. We thank D. Taylor (ESRF Research Manager) for his support

Southern right whales (Eubalaena australis): a new touristic attraction in the Natural Protected Area Bahía de San Antonio, Northeast Patagonia?

In Argentina, the southern right whale (SRW Eubalaena australis) was declared a ‘Natural Monument’ in 1984, protecting the species in waters under national jurisdiction. In the Northeast Patagonian province Río Negro, the SRW is being protected since 1997 by the provincial law 3130. Recently in 2006, this province declared the SRW as a ‘Natural Monument’ in the waters under their jurisdiction by the provincial law 4066. With this law, a commercial whale-watching activity was approved and regulated strictly by provincial authorities, as was the first legalization on ‘immersion with whales’ in Argentina. Data on the sighting frequency (SF), group size and group composition of SRWs were obtained during a preliminary study from March 2007 to February 2008 in the Natural Protected Area Bahía de San Antonio (NPABSA), the most touristic coastal town of this Northeast Patagonian province. Data indicate a peak SF in September with an explicit increase and decrease in the months before and after respectively. The majority of the whales visiting the area were solitary animals (47.7%) followed by non-surface active groups (non-SAG’s; 25%), mothers and calves (M&C; 20.5%) and SAG’s (4.5%). 2.3% of the whale groups could not be classified. Whales in the study area were mainly resting or in a slow travelling behaviour (64%). 22% of the whales were seen socializing whereas only few groups were believed to be engaged in a courtship behaviour (5%). These data might suggest that the area is not a main reproductive area, possibly favouring the region for a whale-based tourism. On the other hand, the unpredictability of their daily presence and the average distance between the whale and the shore raises questions on the viability of such a whale-based business

Abundance estimates of southern right whales (Eubalaena australis) in Bahía San Antonio, Patagonia, Argentina

Aerial surveys were conducted to estimate the abundance of southern right whales in Bahía San Antonio, a bay located in the north-western region of the San Matías Gulf (40°50¿S 64°50¿W), Rio Negro, Patagonia Argentina. The transect for the realization of aerial surveys was designed using the program DISTANCE 6.0 and consisted out of 14 North-South (up to S 40.9°) parallel transect lines with a 2.5km separation, covering a total surface of 418km² (mean coverage probability=0.78). Transect length was chosen according to the safety restrictions of the pilot. Surveys were conducted in good weather conditions and calm sea state (Beaufort 3 or less) using a high-wing Cessna 152 with a flat window. Due to the small size of the aircraft, only one person could fly besides the pilot; observations where therefore made from one side only. Average speed and height of the aircraft was kept constant over the surveys at 90kn (166km/h) and 700ft (213m) respectively. When a group of southern right whales was sighted, data were taken on location (using a Garmin GPSmap 60csx), time and group size. The downward angle to the group perpendicular to the aircraft¿s track was then measured using a hand-held clinometer (Suunto PM5/360PC). Perpendicular distances were calculated by the means of trigonometry using the aircraft¿s altitude and the declination angle to the sighting. Due the flat windows of the aircraft a left truncation distance was set at 150m. Perpendicular distances were also right-truncated at 10% of the observations. The uniform cosine model was chosen in the view of the minimum AIC to model the detection function of southern right whales in the study area. The estimates of g(0)=(s+t)/(s+d) resulted in a correction factor of 0.392 ± 0.456 In total, 7 aerial surveys were conducted in the beginning of August and September 2009, September, October and November 2010, and August, September 2011, resulting in a total flight time effort of 12.4h. In total, 200 whales were seen in 119 whale groups, equally distributed over the entire bay. Group sizes ranged between 1-5 animals with a mean group size of 1.7 animals (SD=0.83). Results show a peak of averagely 136 ± 63 whales in the bay during the month of September, with less than half the amount of whales present in adjacent months. September being the peak month for right whale presence accords to data from other regions in the country. The aerial surveys resulted in the first estimates of southern right whale abundance in this north Patagonian bay and indicate a marked peak during September. Nevertheless, data obtained over the other months remain scarce. More aerial surveys should be conducted to accurately determine the evolution of southern right whale abundance in the study area

A photo-identification catalogue of bottlenose dolphins (Tursiops truncatus) in Northeast Patagonia, Argentina: A tool for the conservation of the species

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

Historical records of southern right whales (Eubalaena australis) of the province Río Negro, North Patagonia, Argentina (1991-2008)

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 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

Seasonal Variation in Abundance and Time-Budget of Bottlenose Dolphins (Tursiops truncatus) in Bahía San Antonio, Patagonia, Argentina

The abundance and time-budget of bottlenose dolphins (Tursiops truncatus) was assessed in Bahía San Antonio, Patagonia (Argentina) in the years 2009 and 2010. A total of 366.4 boat-based survey hours resulted in 64 contact hours with a total of 88 dolphin groups. Mark-recapture abundance estimations, based on 63 identified dolphins, resulted in a corrected maximum estimate of 97 and 83 individuals during winter, and a minimum of 34 and 38 individuals during autumn of 2009 and 2010 respectively. Between 25% and 68% of the population consisted of unidentifiable individuals depending on the season, indicating the high presence of juveniles and calves. Behavioural data indicated that the dolphin¿s time-budget consisted mainly out of resting and feeding, variable over the seasons. Dolphins increased their time feeding and socializing during winter and spring, whereas feeding dropped to a minimum in autumn. During summer, the dolphins spent up to 46% of their time diving, a behaviour presumably associated with a tail out/peduncle-dive foraging strategy. Based on these data, we assume more prey availability during winter and spring (main food source being pelagic fish) and a notable decrease in prey availability during summer with benthic prey species being the main food source. In autumn, even less prey items might be available. Furthermore, the increase in social behaviour during winter and spring combined with a peak in the presence of calves during these seasons, suggests the existence of a mating and calving season. These estimates of abundance are in line with the sizes of other coastal populations of bottlenose dolphins elsewhere in the world, and fit the occupancy patterns described for other coastal areas with small resident communities. The study furthers suggests that dolphins specifically use the study area to rest and feed, and to give birth and raise their young, specifically during winter and spring

Variation in external morphology of resident bottlenose dolphins (Tursiops truncatus) in Bahia San Antonio, Patagonia, Argentina.

Two geographic variations of bottlenose dolphins were described in Argentina (Bastida & Rodriguez, 2003); bottlenose dolphins characterized by their triangular dorsal fin shape (coast of the province of Buenos Aires), and bottlenose dolphins characterized by their falcate dorsal fin shape (coast of the province of Chubut). It was stated that `their clear difference would indicate that both geographic forms are isolated¿ (Bastida & Rodriguez, 2003 p.137). A photo-identification study carried out in Bahía San Antonio (BSA), North Patagonia Argentina, showed a similar variation in external morphology among year-round resident bottlenose dolphins. Out of the 15 bottlenose dolphins considered year-round resident in the bay (Vermeulen & Cammareri, 2009), three are clearly distinguishable by a more falcate dorsal fin, a darker coloration and a notably shorter beak. These individuals, with one associated calf, were first identified in September 2008 and could be re-identified in the study area up to 13 days over all the different seasons. On all occasions, they were re-identified in close association with each other and on 10 occasions in close association with triangular dorsal fin shaped bottlenose dolphins. Behavioural observations made during these associations indicated that these mixed dolphin groups were 18% of their time feeding, 18% socialising, 17% slowly travelling and resting, 16% travelling in medium and fast speed and 7% milling (n=380 min). Although both forms show variations in external morphology, the extent to which this phenotypic variation is genetically correlated remains unknown. A clear insight on the differentiation between these regional forms might have important conservation implications for this species in Argentina