Right whales (Eubalaena australis) that gather on a wintering ground off southern Brazil have been aerial surveyed and photographically identified since 1987. As of 2003 the Brazilian Right Whale Catalogue has 315 different individual whales of which 31 were resighted in other years (23 females, 3 yearlings and 5 whales of unknown age/sex). No resightings occurred prior to 1994 and 71% (n=24) were recorded in 2003. The modal observed interval between calving events is 3 years, consistent with successful reproduction. From 1997 to 2003 the number of reproductive females in the Central Survey Area off Brazil increased at a rate of 29.8% per year (95% CL 15.7, 44.0), and at 14% per year (95% CL 7.1, 20.9) from 1987 to 2003. These rates are significantly different from zero (t=4.133, p<0.009 and t=4.06, p<0.004, respectively). The increase from 1997 to 2003 is higher than the rates observed for right whales in other wintering grounds in the South Atlantic. The right whales on the Brazilian wintering ground are not just transients. Ten percent of the whales have been resighted. If the number of whales continues to increase they will probably expand their distribution throughout their historical 2,400km range and come into increasing conflict with human activities.RESUMO: As baleias francas (Eubalaena australis) que freqüentam a área de concentração reprodutiva de inverno no sul do Brasil têm sido monitoradas através de levantamentos aéreos e fotoidentificadas desde 1987. Até 2003, o catálogo brasileiro de identificação das baleias francas conta com 315 baleias identificadas individualmente, das quais 31 foram reavistadas em outros anos (23 fêmeas, 3 baleias de um ano de idade e 5 baleias de sexo/idade indeterminados). Nenhuma reavistagem foi registrada antes de 1994 e 71% (n=24) foram registradas em 2003. O intervalo modal observado entre o nascimento dos filhotes foi três anos, o que é consistente com o sucesso reprodutivo. De 1997 a 2003, o número de fêmeas registradas com filhotes na Área Central sobrevoada no sul do Brasil aumentou a uma taxa de 29,8% ao ano (95% CL 15,7 -44,0), e de 14% ao ano (95% CL 7,1 -20,9) de 1987 a 2003. Essas taxas são significativamente diferentes de zero (t=4,133, p<0,009 e t=4,06, p<0,004, respectivamente). O aumento de 1997 a 2003 é maior que as taxas observadas para as baleias francas nas outras áreas de concentração reprodutiva de inverno no Oceano Atlântico Sul. As baleias francas na área de concentração reprodutiva de inverno no sul do Brasil não são apenas transientes. Dez por cento das baleias têm sido reavistadas. Se o número continuar a aumentar, pode-se esperar que as baleias francas reocupem sua área de distribuição histórica ao longo de cerca de 2400km de costa, aumentando a possibilidade de conflitos entre as baleias francas e atividades humanas.

The reproductive success of southern right whale (Eubalaena australis) depends on body condition and, therefore, on foraging success. This, in turn, might be affected by climatically driven change in the abundance of the species main prey, krill (Euphausia superba), on the feeding grounds. Annual data on southern right whale number of calves were obtained from aerial surveys carried out between 1997 and 2013 in southern Brazil, where the species concentrate during their breeding season. The number of calves recorded each year varied from 7 to 43 ( = 21.11 ± 11.88). Using cross-correlation analysis we examined the response of the species to climate anomalies and krill densities. Significant correlations were found with krill densities (r = 0.69, p = 0.002, lag 0 years), Oceanic Niño Index (r = −0.65, p = 0.03, lag 6 years), Antarctic Oscillation (r = 0.76, p = 0.01, lag 7 years) and Antarctic sea ice area (r = −0.68, p = 0.002, lag 0 years). Our results suggest that global climate indices influence southern right whale breeding success in southern Brazil by determining variation in food (krill) availability for the species. Therefore, increased frequency of years with reduced krill abundance, due to global warming, is likely to reduce the current rate of recovery of southern right whales from historical overexploitation.

Around 176500 whales were killed in the sub-Antarctic waters off South Georgia (South Atlantic) between 1904 and 1965. In recent decades, whales have once again become summer visitors, with the southern right whale (SRW) the most commonly reported species until 2011. Here, we assess the distribution, temporal pattern, health status and likely prey of SRWs in these waters, combining observations from a summertime vessel-based expedition to South Georgia, stable isotope data collected from SRWs and putative prey and sightings reports collated by the South Georgia Museum. The expedition used directional acoustics and visual surveys to localise whales and collected skin biopsies and photo-IDs. During 76 h of visual observation effort over 19 expedition days, SRWs were encountered 15 times (~31 individuals). Photo-IDs, combined with publicly contributed images from commercial vessels, were reconciled and quality-controlled to form a catalogue of 6 fully (i.e. both sides) identified SRWs and 26 SRWs identified by either left or right sides. No photo-ID matches were found with lower-latitude calving grounds, but 3 whales had gull lesions supporting a direct link with Península Valdés, Argentina. The isotopic position of SRWs in the South Georgia food web suggests feeding on a combination of copepod and krill species. Opportunistic reports of SRW sightings and associated group sizes remain steady over time, while humpback whales provide a strong contrast, with increased sighting rates and group sizes seen since 2013. These data suggest a plateau in SRWs and an increasing humpback whale presence in South Georgia waters following the cessation of whaling.

North Atlantic right whales (NARW), Eubalaena glacialis, were nearly exterminated by historical whaling. Their abundance slowly increased up until 2010, to a maximum of fewer than 500 whales, and since then they have been in decline. We assessed the extent to which the relatively slow increase demonstrated by NARW was intrinsic, and how much could be due to anthropogenic impacts. In order to do so, we first compared calf counts of three populations of Southern right whales (SRW), E. australis, with that of NARW, over the period 1992–2016. By this index, the annual rate of increase of NARW was approximately one-third of that of SRW. Next we constructed a population projection model for female NARW, using the highest annual survival estimates available from recent mark–resight analysis, and assuming a four-year calving interval. The model results indicated an intrinsic rate of increase of 4% per year, approximately twice that observed, and that adult female mortality is the main factor influencing this rate. Necropsy records demonstrate that anthropogenic mortality is the primary cause of known mortality of NARW. Anthropogenic mortality and morbidity has limited the recovery of NARW, and baseline conditions prior to their recent decline were already jeopardizing NARW recovery.

The subtropical and temperate coastal waters of the western South Atlantic are an important calving ground for southern right whales, Eubalaena australis. From 2002 to 2008, data on right whale distribution and habitat characteristics were collected in 14 bays along the coastline of Santa Catarina State, Brazil. Generalized linear models with a negative binomial error distribution were used to determine which environmental (beach morphotype, bay mouth width, bay inclination angle, northsouth and east-west wind components), and temporal (month and year) variables best explained the aggregation pattern of individuals. Our results suggested that both cow-calf pairs and adults unaccompanied by calves prefer bays with dissipative beaches, and that cow-calf pairs apparently avoid bays facing southeast during days of strong east-west winds. The number of sightings peaked in September and tended to increase over the study period. One particular embayment (Ribanceira beach) had considerably higher numbers of animals and may be considered a preferred spot in this calving ground. Our findings contribute to a better understanding of the species' habitat use and ecological requirements and should be taken into account if new management measures are implemented to further increase protection of southern right whales in the region.