Marine megafauna occurrence was recorded in the deep-sea region bordering the abyssal plain ~400 km north-west of Luanda, Angola. The survey took place during an Environmental Baseline Study (EBS), prior to drilling exploration activities, with the goal of characterizing the habitat and biodiversity of the region. Offshore shipboard surveys were conducted during September 2018 in water depths ranging from 2350–3850 m. We recorded daytime sightings of marine mammals and sea turtles and at night made audio recordings using passive acoustic monitoring (PAM) methods focused on capturing the sounds of vocalizing marine mammals. A variety of species were visually detected, including the humpback whale (Megaptera novaeangliae), sperm whale (Physeter macrocephalus), common dolphin (Delphinus spp.), striped dolphin (Stenella coeruleoalba), Atlantic spotted dolphin (S. frontalis), and olive ridley turtle (Lepidochelys olivacea). Acoustic click bouts similar to those made by several odontocete species, possibly including beaked whales, were recorded within the 25–48 kHz range. The humpback whale was the most frequently sighted species, accounting for 56% of mammal sightings, indicating a potential far offshore migratory habitat in this region. Most notably, right whales (probable Eubalaena australis) were visually observed. This is the first confirmed record of right whales in Angolan waters since the early 1900s. As development expands in this offshore region, these data can usefully inform future monitoring and mitigation strategies focused on minimizing impacts to wildlife.

In South-western Atlantic waters, individuals of the southern right whale (SRW) Eubalaena australis spend part of the year (the austral winter and spring) in northern inshore waters where they breed and then migrate to southern feeding grounds during the summer. Mar del Plata (MDP) is located between two main reproductive areas (Península Valdés-Argentina and Santa Catarina-Brazil). The purpose of the present study is to report the presence of SRWs on their journey off the coast of MDP based on sighting records during the past half century. We carried out whale observations through systematic weekly coastal marine mammal surveys in different points of the MDP area from 1966 to 2016. The first SRW sighting was recorded in 1970; since then, sighting frequency has gradually increased, reaching a peak of 28 sightings (N = 63 whales) in 2016. These are unique long-term sighting records of SRWs in Argentina and the first on their journey off the shores of Buenos Aires province. We expect that these results will help local authorities to regulate tourism and other activities in the area and thereby contribute to the conservation of the species.

The historical and contemporary presence of southern right whales (SRWs; Eubalaena australis) around the Falkland Islands (Malvinas) has received little recognition. We assessed SRW occurrence in the Falklands via whaling records, a literature review, systematic surveys (boat, aerial and shore-based), and citizen science sightings. The combined data sources indicated a year-round (peaking in austral summer) presence of SRWs in pelagic areas around the Falklands. In contrast, most nearshore records originated in the austral late autumn and winter (May to August), including a marked increase in sightings along the north-east coast during 2017 compared with previous years. The data support spatio-temporal variation in the use of Falklands waters by SRWs. Pelagic waters appear to comprise summer foraging habitat, and may also be used by animals migrating between the Patagonian shelf and feeding grounds located further south and east. The peak numbers observed in nearshore waters occurred earlier in the winter (July) than those on the Argentinean or Brazilian calving grounds (Aug–Oct). Consequently, some whales may have continued migrating northwards to established breeding areas after departing Falklands waters. A component of the south-west Atlantic population could also be using the islands as a novel wintering destination, for mating and/or socializing (no calving has been confirmed to date). The importance of Falklands waters as a multi-use SRW habitat appears to be increasing. The region is important in the context of addressing current knowledge gaps regarding feeding grounds and migratory corridors highlighted in international SRW conservation and management plans for the wider South-west Atlantic.

Urbanization and intense vessel traffic in coastal areas are obstacles for right whales when selecting breeding and calving grounds. Human activities might be the main cause for the recently observed drop in right whale sightings along the south-eastern coast of Brazil. Information concerning the biology and the activities that can potentially affect the presence of individuals along the coast are essential for management purposes, as well as for the recovery of the species stocks after a period of whaling pressure. This study correlated the occurrence of right whales in the northern limit of the breeding ground in the South-western Atlantic Ocean with local geomorphology, degree of urbanization and oceanographic features to better identify suitable areas for use by these whales. The study area was divided into 14 sub-areas based on local coastal geomorphology and discharge of large rivers. The following five ranking criteria were applied to each sub-area: presence of whaling stations and whaling activity in the past; presence and activity of ports; protection from swell, coastal slope and composition of the bottom substrate. The sub-areas that offered conditions conducive to the presence of right whales received higher scores. The proposed criteria were validated by overlapping the ranking scores with the records of right whales sighted in each sub-area. In south-eastern Brazil, protected areas with sandy bottom and gentle slope were associated with more sightings of female-calf pairs. The criteria can be used as a primary diagnostic indicating suitable sub-areas for right whales in poorly known breeding grounds.

Increasingly, baseline knowledge of habitat preferences and movement patterns of marine species is required to inform anthropogenic developments. The aim of this study was to determine baseline spatio-temporal distribution and habitat preference of cetaceans in the coastal waters of Algoa Bay. Areas of potential conflict with anthropogenic activities were also assessed. Monthly sea-based surveys were conducted between June 2008 and May 2011. A total of 500 cetacean sightings comprising six species were recorded in 106 surveys. Tursiops aduncus (Indo-Pacific bottlenose dolphin), Sousa plumbea (Indian Ocean humpback dolphin), Delphinus capensis (long-beaked common dolphin) and Balaenoptera brydei (Bryde's whale) were observed year-round, while Eubalaena australis (southern right whale) and Megaptera novaeangliae (humpback whale) were recorded from May to December. A large portion of sightings were associated with a Marine Protected Area and shipping zones. Eubalaena australis, T. aduncus and S. plumbea were found inshore (water depths < 12 m), while the other species were associated with deeper waters. Tursiops aduncus were most commonly seen (233 sightings). Megaptera novaeangliae were sighted often in austral winter, with 113 sightings. Only nine D. capensis sightings were recorded. Spatial distributions of species were corrected for search effort to identify habitat preferences. A number of key observations were made, including opportunistic foraging in M. novaeangliae, and the expansion of nursery grounds for E. australis, to include Algoa Bay. Four preferred habitat areas are proposed, providing important information for conservation and management of cetaceans in Algoa Bay. The spatial approach can be used to inform future relevant management decisions elsewhere.

Península Valdés (PV) is the most austral calving ground for the SW Atlantic population of Eubalaena australis. Recent studies indicate that E. australis often feeds in PV mainly in late September and October. A microscopic analysis of food chitin remains found in five whale faeces was performed in the present study in an attempt to obtain baseline knowledge about trophic ecology and degree of use of plankton food available for whales in PV during spring (September–December). The remains in faeces from stranded and live individuals included copepods, other zooplankton and centric diatoms, all of which were characterized. Copepod remains were found to be dominant. Scanning electron and confocal laser scanning microscopes were used for comparative analyses between the mandibular gnathobases found in whale faeces and those obtained from preserved specimens. Mandibular gnathobases were the same in structure and morphometry as those obtained from preserved Calanus australis (copepodites 4–6). The positive relationship observed between the total length and width of the mandibular gnathobases edge of C. australis and those found in faeces allowed us to infer the developmental stages of the copepods ingested by E. australis. Our results indicate – for the first time – the relevant role of C. australis copepodite 5 as main prey for E. australis in PV during the calving season. Copepodite 5 of C. australis accumulates energy-rich lipids. This is energetically attractive for whales and it is the potential reason why E. australis feeds mainly on dense patches dominated by this developmental stage of C. australis.

The southern right whale (Eubalaena australis) was one of the most intensively hunted whales between the 17th and 20th centuries in the southern hemisphere. Recent estimates indicate that today there are around 7000 whales, representing 5 to 10% of its original population. On the other hand, recent studies estimated that the population that migrates to the Brazilian coast grew by 14% from 1987 to 2003. However, there is no information about sex-ratio for adults or for calves in this region, which is an important parameter for understanding the biology of the species. We present here the first estimate of calves' sex-ratio of southern right whales found along the southern Brazilian coast, one of the most important wintering grounds for the species. Sex was molecularly indentified for 21 biopsies collected from calves between 1998 and 2002, along the coast of Rio Grande do Sul and Santa Catarina States, in southern Brazil. The sex-ratio was two females for one male, however, it was not statistically different (χ2 test, α = 0.05; df = 1) from the expected ratio of 1:1. This result is in accordance with the sex-ratio estimated for the species of all ages using external morphology (and behaviour information), as well as for most species of baleen whales.

Presently, there is no information about the functionality of the immune system in the franciscana dolphin (Pontoporia blainvillei), a small dolphin from southern Brazil. As in the case of the franciscana, the population of southern right whale (Eubalaena australis) which inhabits Brazilian waters has not yet been surveyed in what concerns MHC expression. For the first time it was possible to observe the DQB gene expression in skin of these two species of cetacean using RT-PCR. Skin pieces of the animals were collected to RNA extraction. The fragment corresponding to DQB exon 2 was amplified, cloned and sequenced. A total of five alleles were found, one to franciscana and four to southern right whale. The observed dN/dS ratio of 2.77 (P = 0.03) suggests that this gene is under balancing selection pressure (positive Darwinian selection). The sequences indicate that, in both species analysed, the DQB gene is functional.