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During the austral winter, adult female southern right whales Eubalaena australis enter the South African coastal waters to give birth and raise their young. Most births take place over a 4-month period, when the females congregate in specific coastal areas or nursery grounds for up to a recorded maximum of 105 days. At this time, the density of cow-calf pairs in nursery areas can reach as high as 3.2 pairs/km2 over 26 km of coastline. Although a single young is born and suckled exclusively for 7 months to a year, recent observations on nursery grounds include 3 incidents where apparently abandoned/orphaned calves-of-the-year have been seen associating with a minimum of 2-3 different cow-calf pairs over periods of 11-38 days. Attempts to suckle from these females have been noted in 2 of the cases, with the response of the female varying from extreme avoidance to apparent tolerance. In one instance where the observations of the same trio extended over 21 days, the non-offspring appeared to compete at least equally with the offspring, even though the mother directed her evasive tactics more at the non-offspring than her own calf. At the same time, both of the calves exhibited some growth in length when compared with the size of the adult female: their subsequent survival is unknown. Non-offspring nursing in monotocous species is generally rare, and the costs to the female potentially high: this is certainly the case for seasonally feeding mysticetes such as the right whale, where the costs of lactation cannot be recovered until the cow resumes feeding about 4 months after parturition. Hence, it is perhaps not surprising that these are the first recorded observations of contemporaneous nursing attempts by offspring and non-offspring calves of any mysticete. [ABSTRACT FROM AUTHOR]

Heaviside's dolphin (Cephalorhynchus heavisidii) is a coastal delphinid with a limited inshore distribution off the west coast of southern Africa. Knowledge of its habitat usage is an essential precursor to assessing its potential vulnerability to fisheries interactions. Six Heaviside's dolphins (1 male and 5 females) were fitted with satellite-linked transmitters in 2004, and tracked for up to 54 days. The 5 tags fitted to female dolphins transmitted continuously, allowing for analysis of movements at a fine temporal scale. Four dolphins showed an initial avoidance of the capture site by moving over a wider area in the first 2-5 days posttagging than later in the deployment period. All dolphins had used their full home ranges (determined as 100% minimum convex polygons) 5-20 days before tag failure, suggesting measured home ranges were stable at this temporal scale. Home-range estimates using local convex hulls ranged from 301.9 to 1,027.6 km² (90% isopleths) and 875.9 to 1,989.6 km² using the 100% isopleths and scaled positively with body size but varied in shape, usage, and number of core-use areas. Although the distance from shore and depth at which individual dolphins moved varied greatly, all dolphins showed a strong onshore-offshore diurnal movement pattern, generally being closest inshore between 0600 h and noon, and farthest offshore between 1500 h and 0500 h. This pattern is assumed to be related to the movements of their principal prey, juvenile shallow-water hake (Merluccius capensis), which migrate into the upper water column at night. Movements inshore may be associated with rest, socializing, and predator avoidance. [ABSTRACT FROM AUTHOR]

This paper presents evidence of the presence and subsequent loss of postnatal skin in an ecdysis-like process in southern right whales, Eubalaena australis. Individuals whose skin was noticeably uneven, spongy, broken, and often light gray in color formed ≥20% of right whale neonates seen on the South African coast on any day up to and including the 1st week of September. Thereafter ≥85% of calves were of the normal, smooth-skinned appearance. The 50% transition point between the 2 forms occurred on 31 August (95% CI 1.1 days), or about a week after birth. Histological analysis of skin from stranded neonates showed a definite cleavage plane in the midepidermis, the mechanical integrity of which was further compromised by low concentrations of desmosomes and intracellular filaments. We propose that focal edema develops between the cells and forms the cleavage plane, which eventually leads to separation of the outer epidermal cell layer (cf. spongiosis in humans). The movement from the intrauterine to the oceanic milieu, and the osmoregulatory consequences thereof, may be a catalytic factor for this process to occur. This ecdysis may have important consequences for the cyamid fauna of neonatal right whales. [ABSTRACT FROM AUTHOR]

Humpback whales ( Megaptera novaeangliae) from a breeding ground off Gabon (0-4°S) and a migratory corridor/feeding ground on the west coast of South Africa (WSA; 33°S) differ genetically and in catch histories. Interpretation of the population structure is hampered by the lack of data from the intervening 3,500 km of coastline or to the north of Gabon. Here we collate all relevant nongenetic data on humpback whales from Namibia (∼23°S) from 2005 to 2012 and compare these with corresponding data from Gabon (2000-2006) and WSA (1983-2008). Data from Namibia include photographic catalogs of dorsal fin and tail fluke images, seasonal presence, and a photographic assessment of scarring and wounds from cookiecutter sharks ( Isistius sp.). No confirmed photographic identification matches could be made between Namibia and Gabon and only 2 potential matches were made between Namibia and WSA from dorsal fins. Humpback whales in Namibia show a bimodal seasonality in occurrence, with a primary peak in austral winter (July) and a secondary peak in spring (September), but generally low directionality of movement. Whales were never recorded to sing, competitive groups were rarely sighted, and very few calves were observed, making it unlikely that this is a breeding area. The prevalence of killer whale bite scars on flukes was similar at all sites. Fresh bites from cookiecutter sharks were highest in Namibia, intermediate in Gabon, but almost nonexistent in WSA. We propose that animals seen in Namibia in winter are on their northward migration and have intercepted the coast from farther offshore (where cookiecutter sharks occur), whereas animals seen in WSA in spring-summer, where they are feeding during their southward migration, have followed a slow coastwise route within the cold Benguela Ecosystem, thus allowing time for cookiecutter bites to heal. [ABSTRACT FROM AUTHOR]