Thesis (M.Sc.(Zoology))--University of Pretoria, 2001. / Includes bibliographical references.

The general architecture of the skin of the southern right whale, Eubalaena australis, is comparable to that described for other cetacean species. As found in bowhead whales, Balaena mysticetus, of the same family, southern right whales possess an acanthotic epidermis and a notably thick hypodermis. Epidermal rods and extensive papillomatosis support these unique characteristics. A "fat-free" reticular dermis makes the integument of southern right whales more like that of odontocetes than that described for balaenopterids. Skin samples taken in South African and Antarctic waters showed evidence of superficial moultin'g throughout the austral winter and in mid-summer. Unidentified "microfIora" and fungal microbes were detected on the skin of whales sampled in both South African and Antarctic waters. The predominance of "microfIoral" aggregations on cows and calves in OctoberlNovember suggests that these micro-organisms are acquired in coastal waters. A Candida-like invasive fungal infestation of the skin of a stranded neonate was recorded for the first time in this species and may be related to the demise of this animal. The film-forming diatom, Bennettella [Cocconeis] ceticola, was not detected on any skin samples. This may imply that southern right whales exhibit high cellular proliferation rates, which prevent diatomaceous films from forming. Neonatal southern right whales undergo a spectacular form of ecdysis approximately 6-7 days after birth. Histologically, "rough-skinned" neonates possess a distinct "fault line" above the distal tips of the dermal papillae, that becomes characterised by intercellular oedema, which causes all the cell layers above the plane to separate from those below it. The fatty acid composition of the dermal and hypodermal layers provides indications of prey species consumed as well as reflecting physiological processes within the digestive system of the southern right whale. Total lipid values in the blubber of late season cows and calves are reported for the first time. A new hand¬held biopsy system for collecting deep-core integument samples from free-swimming balaenids is described. It is a practical and cheaper alternative to projectile systems and the head design allows for the collection of samples that can be used for multidisciplinary research on right whales (e.g. histology, toxicology and blubber composition studies). / Thesis (PhD (Zoology))--University of Pretoria, 2006. / Zoology and Entomology / unrestricted

Distributional data from 32 years of aerial surveys of southern right whales (Eubalaena australis) along the south coast of South Africa were investigated using GIS, over a variety of spatial and temporal scales to test whether their discontinuous yet predictable distribution is related to environmental characteristics. Most whales were found in areas that provided reasonable protection from open ocean swell and seasonal winds as well as having sedimentary floors with gentle slopes, despite these characteristics being less common. Correlation type analyses with whale density only showed significance at the broadest scale. Cow-calf pairs were found significantly closer to shore and in shallower water than unaccompanied whales; they also segregated longshore in nursery areas. No relationship between reproductive success and distribution was found except a higher than expected incidence of neonatal strandings in areas dominated by unaccompanied whales. Habitat choice at this time of year was concluded to be related both to energy conservation for calves and lactating females and protection of neonates. / Dissertation (MSc (Zoology))--University of Pretoria, 2006. / Zoology and Entomology / unrestricted

Guidelines for sustainable swim-with tourism for large whales are not welldeveloped, as researchers have focused on delphinids. Nations that signed the Convention on Biological Diversity at the Earth Summit in Rio de Janeiro in 1992 are obligated to consider sustainable use principles when allowing new ecotourism activities, yet the fast-growing worldwide swim-with-whales industry is lacking the research needed to create successful management guidelines that can be implemented by local communities. From September to November of 2005 and July to October of 2006, I collected movement and behavioral state data for southern right whales in proximity of swimmers at Península Valdés, Argentina. Whales were observed before, during, and after a series of directed interactions with swimmers. I quantified the behavioral and movement effects relative to group composition of whales (mother/calf pairs, juveniles or adult/mixed groups) and activity level of swimmers. Group composition had a significant effect on the response of whales to swimmers. Swimmer activity level did not substantially affect the reaction of whales. Resting and socializing activities significantly decreased and traveling activities significantly increased when boats approached and when swimmers entered the water. Resting and socializing bout length in the presence of swimmers decreased to less than a third of the length of bouts when swimmers were not present. Whales swam faster, reoriented more often, and followed a less linear path during interactions. Effects were greater for mother/calf pairs than juveniles, while mixed adult/juvenile groups showed no significant changes in behavior or movement. The initial reaction of whales to the approach of the boat and the entry of swimmers into the water was a good predictor of the magnitude of effects on the behavior and movement patterns of the whale. Increased levels of activity are a concern for the whales that are resting and not feeding in this area. To provide quality resource management guidelines for this activity, additional research is needed to determine long-term effects of boat and swimmer activities on the behavior of whales. It is also important to obtain energetic data for right whales to determine the magnitude of impacts.

The site fidelity of humpback and southern right whales in Algoa Bay was investigated as a baseline study to examine the importance of this area for the future conservation of these species. An absence of whales since the 1980’s from Algoa Bay and more frequent sightings of southern right and humpback whales during a survey conducted between 2008 and 2011 in Algoa Bay led to the present photo-identification study. Data were collected from boat-based surveys along the coastline in 2015 and 2016 and data from a previous boat-based study during 2008-2011 assessing the occurrence of all cetaceans in Algoa Bay were added. A cumulative number of 96 individual southern right whales and 184 individual humpback whales were identified from callosity patterns and dorsal fins, respectively, over this period in Algoa Bay. A low resighting rate for both species was observed within (6.25 for southern right whales & 6.98% for humpback whales) and between years (1.04% for southern right whales & 9.24% for humpback whales) with mainly individual adult humpback whales being resighted. In contrast, all southern right whale resightings were confirmed to be mother-calf pair individuals. The timing of monthly sightings and resightings of mother-calf pair individuals in the bay may suggest that this area may serve as a fairly new nursery area for southern right whales and as a possible migratory corridor for humpback whales during their migrations to and from their breeding grounds. The sighting distribution within the bay suggest that mother-calf pairs are located closer inshore and further away from the shipping activities on the eastern side of the bay in the proximity of two operational ports. This forms an important baseline for future monitoring to assess the effect of increased shipping activity in the bay on the breeding behaviour of the whales. The site fidelity of humpback and southern right whales in Algoa Bay was investigated as a baseline study to examine the importance of this area for the future conservation of these species. An absence of whales since the 1980’s from Algoa Bay and more frequent sightings of southern right and humpback whales during a survey conducted between 2008 and 2011 in Algoa Bay led to the present photo-identification study. Data were collected from boat-based surveys along the coastline in 2015 and 2016 and data from a previous boat-based study during 2008-2011 assessing the occurrence of all cetaceans in Algoa Bay were added. A cumulative number of 96 individual southern right whales and 184 individual humpback whales were identified from callosity patterns and dorsal fins, respectively, over this period in Algoa Bay. A low resighting rate for both species was observed within (6.25 for southern right whales & 6.98% for humpback whales) and between years (1.04% for southern right whales & 9.24% for humpback whales) with mainly individual adult humpback whales being resighted. In contrast, all southern right whale resightings were confirmed to be mother-calf pair individuals. The timing of monthly sightings and resightings of mother-calf pair individuals in the bay may suggest that this area may serve as a fairly new nursery area for southern right whales and as a possible migratory corridor for humpback whales during their migrations to and from their breeding grounds. The sighting distribution within the bay suggest that mother-calf pairs are located closer inshore and further away from the shipping activities on the eastern side of the bay in the proximity of two operational ports. This forms an important baseline for future monitoring to assess the effect of increased shipping activity in the bay on the breeding behaviour of the whales.

Mysticetes, or baleen whales, make up one of two sub-orders of the Order Cetacea within the Class Mammalia (Drikamer et al, 2013). It contains three families, each characterized by baleen plates (Drikamer et al, 2013). These baleen plates consist of keratin that replaced the tooth structures for feeding in these mammals (Drikamer et al, 2013). Other biological characteristics of these animals include paired external nares (blowholes), a sternum consisting of a single bone, symmetrical skull and the most conspicuous of all, the body length of between ten to thirty metres (Drikamer et al, 2013). It is thought that the size characteristic was probably the main factor when categorising them as cetaceans, with the Latin word ‘Cetus’ referring to ‘sea monster’ (Carnaby, 2006). In this literature review, the focus will fall on two species of mysticetes from separate families, namely that of the southern right whale, Eubalaena australis of the Balaenidae family, and the humpback whale, Megaptera novaeangliae of the Balaenopteridae family. Emphasis in this review will fall on the aspect of site fidelity of the mother-calf pairs.

Southern right whale vocalisations recorded in Walker Bay, South Africa, between June and November 1999, were analysed to investigate the acoustic repertoire, the relationship between calling behaviour and whale presence, the proportions of vocal and silent whales, and of recorded calls from unseen whales, and the evidence for vocal individuality. This marks the first study of right whale vocalisation in South African waters. A simple matrix system with the axes acoustic contour and onset frequency described twelve call types. Analysis of call use over time indicated that some calls, as well as broadband gunshots, clustered strongly in bouts of differing lengths, and that their relative use varied over the season; the repertoire and its classification was compared with other accounts of right whale vocalisation [chapter one]. A generalised linear model explained the variation in the overall call rate in terms of the numbers of whales present, month and wind direction. The overall call rate, for each month and in all wind conditions, rose with increasing whale numbers to a plateau at between ten and fifteen whales, and then declined as whale numbers rose further, suggesting that the social motivation for vocalising was progressively reversed. An inverse linear relationship between call rate per whale and whale abundance was clearly demonstrated over the whole season, indicating that call rates were unreliable as an indicator of whale numbers [chapter two]. A dual-axis, three-element hydrophone array suspended at 5m from floating buoys was designed to assign whale vocalisations to calling whales. The array was calibrated with an overall mean error of 3°. Bearings to calling whales were calculated using correlelograms, and compared with the observed positions of whales. On average 31% of low up (upwardly inflected) calls and 11% of medium and high down (downwardly inflected) calls came from whales not sighted from the boat; up to just under half of the whales sighted from the boat were silent. This indicates the importance of integrating visual and acoustic data when estimating whale numbers [chapter three]. In characterising individuality in vocalisations, we used cluster analysis of acoustic properties of whale calls to derive the Euclidean distances (a measure of similarity) between each possible pair of calls within a continuous recording session. Calls clearly from different whales (distant call pairs) were more dissimilar than calls possibly from one whale (‘close’ call pairs), lending support to the hypothesis of vocal individuality. The similarity between ‘close’ up calls was greatest when the calls were within 0.5 minutes of each other, and declined progressively, up to a separation of 6.5 minutes, as the likelihood of both calls being from one whale declined, indicating individual bout-calling. Medium and high down (downwardly inflected) calls, associated with surface active groups (SAGs), and thought by other researchers to be produced by the focal female, were more similar within any given SAG than when compared across SAGs. This evidence strongly suggests that southern right whales produce individually distinctive vocalisations [chapter four]. / Thesis (PhD)--University of Pretoria, 2010. / Zoology and Entomology / unrestricted

South African southern right whales (SRWs; Eubalaena australis) have been studied intensively since 1969, and annual aerial surveys between 1971 and 2006 indicate a predominant 6.9% annual population growth rate – a conservation success story after the species’ legal protection from commercial whaling in 1935. However, the prevalence of South African SRW unaccompanied adults (non-calving adults) and cow-calf pairs dropped sharply after 2009 and 2015, respectively. Additionally, the calving interval of many female South African SRWs has shifted from a three-year cycle to a four- or five-year cycle, since 2010, suggesting calving failure. This has resulted in a decrease in the population growth rate from 6.9% between 1971 and 2006, to 6.5% in 2017. SRWs are capital breeders that meet migratory and reproductive costs through seasonal energy intake, leading to strong links between their calving and foraging success. The anomalous trends in the South African SRW population have therefore raised concern about the ecological status of its broad feeding range in the Southern Ocean and ultimately about its continued population recovery. This necessitated investigation firstly into the influence of large-scale global climate drivers, Antarctic winter sea-ice extent and summer ocean productivity on the calving output of the South African SRW population. Auto-regressive integrated moving average models revealed significant model performance improvement through the inclusion of the Oceanic Niño Index (a key measure of El Niño events), the Antarctic Oscillation (the leading mode of atmospheric variability in the Southern Ocean) and chlorophyll a concentrations. The findings indicate that the South African SRW calving output appears closely influenced by not only the species’ life cycle, but also by foraging ground productivity and global climate. Secondly, the foraging strategies of South African SRWs during the 1990s (i.e. a period of high calving rates) and the late 2010s (i.e. a period of low calving rates), were assessed, through the analyses of stable carbon (δ13C) and nitrogen (δ15N) isotope values in SRW skin biopsy samples (n = 122). Results show that South African SRWs underwent a dramatic northward shift in foraging location, as well as a diversification in foraging strategy, between the 1990s and 2010s. Bayesian mixing models suggest that during the 1990s, the population foraged on prey with isotopic values similar to krill from around South Georgia. By contrast, in the 2010s, it is inferred that the population foraged on prey with isotopic values consistent with prey found in the waters of the Subtropical Convergence, Polar Front, and Marion Island. This shift could represent a new strategy to cope with changes in the availability of preferred prey or changes in habitat productivity. However, the co-occurring reproductive declines show that altering foraging strategies may not be sufficient to successfully adapt to a changing ocean. Overall, the results of this dissertation advocate that South African SRWs have recently been affected by environmental change at their foraging grounds, in turn affecting their reproductive success. Their predictive coastal presence and the existing long-term monitoring suggest that the species should be regarded as an indicator species – illustrative of climate change impacts in Southern Ocean ecosystems. / Dissertation (MSc ((Zoology))--University of Pretoria, 2020. / Zoology and Entomology / MSc (Zoology) / Restricted

Data collected during boat-based and aerial surveys were used to describe population structure, movements, temporal patterns of migration and skin condition of humpback whales in breeding sub-stock C1-S off southern Africa. Results confirmed that the migration route along the south coast of South Africa is linked to the winter ground off Mozambique. A lack of exchange between breeding sub-stocks C1-N and C1-S was found, suggesting that these are independent of each other. Molecular analysis revealed unexpected levels of population structure between the migration route and the winter ground of C1-S, as well as the possibility that this migration route is also utilised by some individuals from breeding sub-stock C3. A skin condition of unknown aetiology that primarily affects humpback whale mother-calf pairs was identified. The first assessment of its prevalence and severity was made, providing a baseline for future monitoring. Humpback whale abundance in an inshore region of Bazaruto Archipelago, Mozambique was estimated and attempts were also made to use the limited information off Plettenberg Bay/Knysna, South Africa. In addition to improving our understanding of humpback whales from Breeding Stock C, knowledge about another baleen whale species utilising the southwest Indian Ocean was extended. The first evidence of southern right whale presence off the coast of Mozambique since the cessation of whaling was documented. It remains unknown whether this is a remnant sub-stock or the recovering South African sub-stock reoccupying its historical range.