Academic literature on the topic 'Southern Hemisphere humpback whale'

To investigate the incidence of non-lethal predation in Southern Hemisphere whales, more than 3400 fluke-identification photographs from resight histories of 1436 east Australian humpback whales were examined for evidence of predatory markings. Photographs were obtained from 1984 to 1996 at various locations along the east coast of Australia, from northern Queensland to southern New South Wales. Photographs were classified in terms of the level and type of scarring. The possible predator and whether the markings appeared fresh were also noted. In all, 17% of identified east Australian humpbacks possessed some form of predatory scarring, 57% of which was minor and 43% major. Almost all predatory scarring was consistent with that inflicted by killer whales. Only three whales demonstrated an increase in the level of predatory scarring after their first sightings. Two incidents of fresh scarring were recorded, and one fatal killer whale attack on a humpback whale calf was directly observed. The overall level of predatory scarring found in this study is comparable to those found in studies for Northern Hemisphere humpback whales. The low incidence of adult whales showing their first sign of predatory scarring after their initial sighting, and the small number possessing recent scarring, support the idea that east Australian humpback whales experience most predatory attacks early in life.

Southern Hemisphere humpback whales ( Megaptera novaeangliae ) inhabit a wide variety of ecosystems including both low- and high-latitude areas. Understanding the habitat selection of humpback whale populations is key for humpback whale stock management and general ecosystem management. In the Atlantic sector of the Southern Ocean ( ASSO ), the investigation of baleen whale distribution by sighting surveys is temporally restricted to the austral summer. The implementation of autonomous passive acoustic monitoring, in turn, allows the study of vocal baleen whales year-round. This study describes the results of analysing passive acoustic data spanning 12 recording positions throughout the ASSO applying a combination of automatic and manual analysis methods to register humpback whale acoustic activity. Humpback whales were present at nine recording positions with higher acoustic activities towards lower latitudes and the eastern and western edges of the ASSO . During all months, except December (the month with the fewest recordings), humpback whale acoustic activity was registered in the ASSO . The acoustic presence of humpback whales at various locations in the ASSO confirms previous observations that part of the population remains in high-latitude waters beyond austral summer, presumably to feed. The spatial and temporal extent of humpback whale presence in the ASSO suggests that this area may be used by multiple humpback whale breeding populations as a feeding ground.

Humpback whale song is an extraordinary example of vocal cultural behaviour. In northern populations, the complex songs show long-lasting traditions that slowly evolve, while in the South Pacific, periodic revolutions occur when songs are adopted from neighbouring populations and rapidly spread. In this species, vocal learning cannot be studied in the laboratory, learning is instead inferred from the songs' complexity and patterns of transmission. Here, we used individual-based cultural evolutionary simulations of the entire Southern and Northern Hemisphere humpback whale populations to formalize this process of inference. We modelled processes of song mutation and patterns of contact among populations and compared our model with patterns of song theme sharing measured in South Pacific populations. Low levels of mutation in combination with rare population interactions were sufficient to closely fit the pattern of diversity in the South Pacific, including the distinctive pattern of west-to-east revolutions. Interestingly, the same learning parameters that gave rise to revolutions in the Southern Hemisphere simulations gave rise to evolutionary patterns of cultural evolution in the Northern Hemisphere populations. Our study demonstrates how cultural evolutionary approaches can be used to make inferences about the learning processes underlying cultural transmission and how they might generate emergent population-level processes. This article is part of the theme issue ‘Vocal learning in animals and humans’.

In the central Indian Ocean, humpback whales (Megaptera novaeangliae) are rare. Records from southern India, Sri Lanka, Maldives and the Chagos Archipelago (n=67) were compiled and show a bimodal pattern of seasonal occurrence. Those occurring during the northern winter (December to April) are known to belong to the Arabian Sea humpback whale population. There have been no humpback whales recorded in Maldives during the northern winter since 2001, suggesting a possible range contraction for the Arabian Sea humpback whale population. Humpback whales occurring during the southern winter (June to October) are assumed to belong to the southwest Indian Ocean population (IWC breeding stock C). In this case, numbers of opportunistic sightings are increasing and the population appears to be spreading northwards as it recovers from commercial whaling, with several recent southern winter records from as far north as 5°N in northern Maldives and southern Sri Lanka. For this southern hemisphere population, calves are first seen in August, with numbers of calves increasing in September and October. For both populations, interactions with regional fisheries, particularly pelagic gillnetting, may be a major cause of mortality.

Intensive commercial whaling caused significant declines in Southern Hemisphere humpback whale (Megaptera novaeangliae) populations. In Fiji, land-based humpback whale surveys undertaken from 1956 to 1958 documented maximum weekly counts of more than 150 humpback whales in parts of the Bligh waters. These records provide an invaluable point of comparison to present-day observations as they occurred immediately prior to very large humpback whale catches in Antarctic waters to the south – and on potential migration routes – of humpback whales breeding in Fijian waters. We report here on a three-year (2010–2012) land-based survey also conducted in the Bligh waters during which a total of 33 individuals over 480 h were counted from Ovalau Island and 68 individuals over approximately 300 h were observed from Makogai Island. These findings suggest a large decrease in numbers of humpback whales seen in Fiji waters since commercial whaling operations.

Some humpback whales migrate annually from Antarctic feeding grounds to the seas around the Tongan Islands to give birth and mate. The Tongan humpbacks are considered part of Southern Hemisphere Group V that splits during migration, some swimming to Eastern Australia and others to various Polynesian Islands. During this time long complex songs are produced. The song is thought to be a male breeding display and may serve either as an intra-sexual or an inter-sexual signal or both. It is in a constant state of change that occurs every season. Since these changes are directional they cannot be described by drift, and singers incorporate changes as they occur, thus song must be shared through cultural transmission. This investigation describes the cultural changes that occurred in 158 songs recorded from Tongan humpbacks through the 1990s. The rate of change differed within years, some themes were retained for as much as five years and others were lost after only two years. The farther apart the years the less similar are the songs, as in the humpback songs of the Northern Hemisphere. The largest number of changes seems to have occurred in the early 1990s where all themes seemed to have been lost and new ones originated. What initiates these changes remains speculative, but we assess some hypotheses in relation to humpback whale behaviour and cultural transmission in avian song.

Humpback whales ( Megaptera novaeangliae ) annually undertake the longest migrations between seasonal feeding and breeding grounds of any mammal. Despite this dispersal potential, discontinuous seasonal distributions and migratory patterns suggest that humpbacks form discrete regional populations within each ocean. To better understand the worldwide population history of humpbacks, and the interplay of this species with the oceanic environment through geological time, we assembled mitochondrial DNA control region sequences representing approximately 2700 individuals (465 bp, 219 haplotypes) and eight nuclear intronic sequences representing approximately 70 individuals (3700 bp, 140 alleles) from the North Pacific, North Atlantic and Southern Hemisphere. Bayesian divergence time reconstructions date the origin of humpback mtDNA lineages to the Pleistocene (880 ka, 95% posterior intervals 550–1320 ka) and estimate radiation of current Northern Hemisphere lineages between 50 and 200 ka, indicating colonization of the northern oceans prior to the Last Glacial Maximum. Coalescent analyses reveal restricted gene flow between ocean basins, with long-term migration rates (individual migrants per generation) of less than 3.3 for mtDNA and less than 2 for nuclear genomic DNA. Genetic evidence suggests that humpbacks in the North Pacific, North Atlantic and Southern Hemisphere are on independent evolutionary trajectories, supporting taxonomic revision of M. novaeangliae to three subspecies.

The photo-identification catalogue of humpback whale tail flukes from Oman was compared with those from Antongil Bay, Madagascar and study sites in South Africa and Mozambique collectively termed the ‘East African Mainland’. No matches were found, supporting other lines of evidence that the humpback whales studied off the coast of Oman form part of a discrete Arabian Sea population, which adheres to a Northern Hemisphere breeding cycle, and has little or no ongoing exchange with the nearest neighbouring populations in the southern Indian Ocean. While the sample size from Oman is small, and low levels of ongoing exchange might not be detected in this type of catalogue comparison, the study nonetheless emphasises the need to pursue research and conservation efforts in the known and suspected range of the Endangered Arabian Sea humpback whale population.

Estimating demographic parameters is essential to assessing the recovery potential of severely depleted populations of marine mammal species such as the baleen whales, which were decimated by commercial whaling of the past century. The Oceania humpback whale Megaptera novaeangliae population is classified as endangered by the IUCN because of low numbers and a slow recovery rate. Nevertheless, an anomalously strong increase has recently been detected in the New Caledonia breeding population. To determine the drivers of population growth, reproductive parameters were estimated for the first time for a humpback whale population of Oceania. Based on an extensive monitoring program (1995-2018), recapture histories were reconstructed for 607 females and incorporated in multi-event capture-recapture models. As the females’ ages were generally unknown (87%), 2 models with contrasting age scenarios were investigated. For females of unknown age, the mature scenario assumed maturity at the first encounter, while the immature scenario assumed immaturity within 7 yr after the first encounter, unless the female was encountered breeding. These models respectively resulted in a calving interval of 1.49 yr (95% CI: 1.21-2.08) or 2.83 yr (95% CI: 2.28-3.56) and a calving rate of 0.67 or 0.35. The relatively high calving rate modelled by the mature model is consistent with high pregnancy rates recently observed in the migratory corridors of the Kermadec Islands and on the feeding grounds of the Antarctic Peninsula. Therefore, our results suggest that the recovery of the New Caledonia humpback whale population from past exploitation may be partially driven by an increased reproductive capacity.

We report the first documented movement of an individual humpback whale between the eastern South Pacific stock off Ecuador and the western South Atlantic stock off Brazil. This constitutes the first record of a humpback whale in both the Atlantic and Pacific breeding grounds off South America, and one of a small number of inter-oceanic movements documented to date. It is possible that, even at quite low levels, this movement of individuals between breeding grounds contributes to the current high level of mtDNA diversity in these once-depleted Southern Hemisphere populations. When first sighted, the whale was accompanied by a young calf, and is therefore identified as an adult female. This movement to a different and distant breeding ground is the first reported by a reproductively mature female, and shows that extreme long-distance travellers among humpback whales are not restricted to young males.

Southern hemisphere humpback whales are high-fidelity krill predators relying on high Antarctic krill biomass to survive and undergo successful reproduction. During the austral summer, humpback whales consume large quantities of krill and build up their blubber reserves. The rest of the year is spent migrating to temperate waters and back while relying on accumulated energy reserves. This expected reliance on Antarctic krill underpins our understanding of Southern hemisphere humpback populations. Their Northern hemisphere counterparts are however known to be more flexible in their feeding habits, and recent work has shown that the Southern hemisphere populations are capable of a certain feeding plasticity, with multiple visual reports of supplementary feeding during the migration, and evidence of anomalous feeding observed in baleen plates. Due to the dependency of Antarctic krill on sea-ice duration and extent for its larval recruitment, the entire Antarctic sea-ice ecosystem is expected to destabilise in a changing climate. The resulting effects on high-fidelity krill predators, such as humpback whales, are unknown. Detailed, long-term information regarding current and past diet, migration and metabolism of humpback whales are needed to successfully assess possible trophodynamic variability, and to differentiate between the natural feeding plasticity of this species and population responses to climate driven environmental change. This thesis aims to evaluate whether Australian humpback whale populations display feeding plasticity in their prey choice and/ or feeding locations.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>Griffith School of Environment<br>Science, Environment, Engineering and Technology<br>Full Text

This thesis describes the novel use of multiple steroid hormone analysis to investigate and gain understanding of previously unknown aspects of the endocrinology and reproductive biology of the Southern Hemisphere humpback whale (Megaptera novaeangliae). Steroid hormones are a class of structurally related molecules that function as messengers in a variety of important physiological processes (e.g. salt homeostasis, immune system, sexual development and reproductive cycles). A number of endogenous steroid hormones have been identified as critical for reproduction (e.g. androgens, progestogens, oestrogens) and stress response (e.g. corticosteroids) in mammals. Understanding the species-specific roles and baseline levels of endogenous steroid hormones enable these compounds to be used as biomarkers of reproductive status and stress exposure. The use of steroid biomarkers for these purposes promises to be extremely advantageous in cetacean species, since other approaches often require increased time and resources. However, the collection and interpretation of steroid hormone data in the humpback whale is currently limited by methodological issues (e.g. challenging sampling, difficult comparison between sample types, analytical approach restricted to single hormone analysis), and by a general lack of detailed knowledge of the humpback whale endocrine system. Collection of biological samples from cetaceans is inherently difficult. In particular, free-swimming individuals of baleen whale species, including humpback whales, cannot be kept in captivity, nor they can be immobilised for sampling. Contemporary studies have demonstrated that steroid hormones analysis is viable in baleen species through the use of remotely collected tissues and fluids (i.e. faeces, blow, blubber). The seasonal migration of the humpback whales from the Antarctic feeding areas to the tropical breeding grounds, however, imposes further restrictions in regard to sample types and timing of collection. To date, blubber is the only matrix employed for steroid analysis in this specie and comprehensive seasonal steroid hormone changes have not being studied. Blubber is a lipid-rich tissue, able to sequester traces of steroid hormones from circulation. This is advantageous as multiple types of steroid hormones are likely to be present in this tissue. However, steroid hormones in blubber, particularly those at trace levels, can only be quantified by using sensitive techniques that need to accommodate the presence of lipids in the matrix. Enzyme immunoassay (EIA) is typically used for steroid hormone analysis in complex matrices, as it requires minimal sample preparation. Although EIA provides high sensitivity, its precision can suffer due to the indirect nature of the measurements and by the possibility of cross-reactivity. A significant disadvantage of employing EIAs for the investigation of species-specific endocrinology is that each EIA quantifies only a single steroid hormone, or a single class of steroid metabolites in its ensemble. Single steroid hormone measurements can be misleading, as steroid hormones act in concert. The same steroid hormone can have different roles and increase or decrease in concentration to accommodate different biosynthetic pathways (e.g. acting as an active metabolite, or as a precursor to or degradation product from other steroids). Liquid chromatography coupled with tandem mass-spectrometry (LC-MS/MS) represents an alternative to EIAs, as it can provide accurate and precise quantification of multiple steroid hormones from the same sample portion. Major issues in LC-MS/MS methods include the coelution of multiple analytes or the interference of matrix components, which can sometimes be resolved only through a trade-off between analyte resolution and sensitivity. These challenges can however be identified prior to the analysis, and overcome, at least partially, by optimising the sample extraction and cleanup. This thesis aimed to adapt and validate a LC-MS/MS method for extracts of humpback whale blubber, and to evaluate use of multiple steroid hormone measurements in relation to reproductive status and possible stress exposure from free-ranging individuals. Blubber samples from stranded humpback whale carcasses were initially employed to assess the applicability, scope, and repeatability of a LC-MS/MS method for the analysis of multiple steroid hormones (Chapter 2). The method, initially developed for bottlenose dolphin (Tursiops truncatus) blubber, proved to be applicable to the comparatively lipid-rich humpback whale outer blubber. Levels of five corticosteroids and six reproductive steroids (including androgens, progestagens and oestrogens) were determined in humpback whale blubber, and ten of these analytes could be quantified with high accuracy (error on amended samples < 15%) and repeatability (percent standard deviation < 15%). The multi-steroid hormone profiles obtained by the stranded carcasses were also investigated as potentially indicative of the endocrinological responses of some of the whales to stress exposure. Subsequently, the LC-MS/MS method was applied to biopsy extracts from freeswimming humpback whales collected at two time points of the whale breeding season over multiple years. The application of this methodology to live biopsies resulted in a smaller number of analytes detected, predominantly as an effect of the corticosteroid analytes being lower in concentration or undetectable in these samples. The quantified steroid hormones provided, however, novel insights into endocrinology and reproductive biology of female (Chapter 3) and male (Chapter 4) humpback whales. In Chapter 3, we show how the use of a previously validated pregnancy concentration threshold for the single hormone progesterone failed to detect any pregnant females based on LC-MS/MS analysis of blubber extracts from 23 females sampled while approaching the breeding grounds. However, by considering multiple steroid profiles including androgens and cortisol, we suggest that relatively high blubber concentrations of androstenedione may distinguish pregnant individuals during the last month of gestation. This hypothesis is supported by reference to steroid hormone measurements through pregnancy in evolutionarily related mammal species, although further work (e.g combining photo identification) is required to provide conclusive evidence. In addition, the same previously validated progesterone threshold resulted in an unexpectedly low proportion of pregnant females (3%) from among 29 females departing the breeding grounds. This prompted the suggestion of a new lower progesterone concentration threshold for assignment of early pregnancy status. In Chapter 4, the seasonal variations in blubber steroid hormone concentration in males are examined through the breeding season. Lowering of testosterone during the expected peak in reproductive activity suggests asynchronicity between blubber testosterone levels and male fertility. Correlation analyses among multiple hormone couples are used to postulate the changes in biosynthetic pathways behind the large interseasonal variations in steroid concentrations. These large intra-season variations in blubber androgens and a contrasting relationship with cortisol across the migration, encourages further investigation on the effects of age and sexual maturity on concentrations of these two hormones. This is necessary before they can be used as biomarkers for reproductive status or stress exposure. An application of how some of the multi-hormone information can be used to improve humpback whale monitoring is provided in Chapter 5. Early and late pregnancy diagnoses as formulated in Chapter 3, are combined with body condition information simultaneously measured in the same female individuals. Superior body condition among late-pregnant female corroborated previous observations that females would increase their feeding opportunities before parturition in order to support, as capital breeders, the combined energetic cost of migration and lactation. In contrast, no relationship was found between whales identified as early pregnant and their body condition compared to the rest of the migrating females. These results suggest that body condition and fertility might not be directly related during the breeding season. Instead, annual winter-feeding efficiency might be more important than accumulated energy stores in guaranteeing the annual reproductive success in females of this species. Overall, by analysing for a larger suite of steroid compounds and focusing on a comparatively less studied period of the migration, this work revealed some limitations of the current methodology used to measure steroid hormones in humpback whales. These findings enhance our knowledge of the humpback whale endocrine system and provide new approaches for the diagnostic use of steroid hormones profiles in free-swimming humpback whales.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>School of Environment and Sc<br>Science, Environment, Engineering and Technology<br>Full Text

Millions of hazardous chemicals are synthesized each year. Their release often represents a risk for the environment and biota. As part of a broader effort to investigate the accumulation and effect of emerging chemicals of concern in the Antarctic sea-ice ecosystem, this thesis focuses upon exposure and effect assessment in southern hemisphere (SH) humpback whales (Megaptera novaeangliae). Cetaceans traditionally represent ideal targets for exposure assessment to Persistent Organic Pollutants (POPs), that is chemicals identified as persistent, bioaccumulative, toxic and capable of long-range environmental transport. Their extended life span and high proportion of body fat render cetaceans susceptible to accumulation of elevated burdens. Southern hemisphere humpback whales feed almost exclusively on Antarctic krill (Euphasia superba) and thus represent second order consumers of the Antarctic sea-ice ecosystem. Exposure assessment consisted of targeted analysis of short-chain chlorinated paraffins (SCCPs) included under the Stockholm Convention (SC) in 2017, and brominated structures listed in 2009 as well as novel, naturally occurring brominated structures, already detected at lower trophic levels of the Antarctic sea-ice ecosystem. SCCPs were targeted in stranded specimens and were detected in 77.7 % of samples, representing the first detection of SCCPs in any mysticetes or any Antarctic foraging marine mammal.Blubber samples from free-swimming and stranded specimens were dedicated to the analysis of the modern category of POPs, polybromodiphenilethers (PBDEs), and a naturally occurring brominated compound, 2,4,6-tribromoanysole (TBA), the chemical structure of which closely resembles PBDEs, flagging the possibility of similar toxic action. Humpback whale PBDEs profiles were dominated by tetra- and penta- congeners, supporting a single previous study on PBDE accumulation in Southern hemisphere humpback whales feeding in the Antarctic Peninsula region. Further, the detection of decaBDE adds support for the local emissions or particle bound transport to Antarctica. PBDE congeners were detected in all samples analysed, whilst TBA was 88 detected in 80% of samples. Upon establishing accumulation of three novel chemical groups in the Antarctic sea-ice ecosystem, species-specific effect assessment was performed through cytotoxicity assessment implementing the newly established immortalized humpback whale fibroblast cell line (HuWaTERT). Two endpoints were targeted, namely membrane integrity and metabolic activity following 24h exposure to an SCCP cocktail, BDE-47, BDE-99, TBA. Each assay also incorporated the assay reference chemical, p,p’-DDE. The four chemicals did not show a dose-dependent response comparable to the one produced by the reference chemical. Whilst p,p’-DDE induced a decrease of both metabolic activity and membrane integrity, the cell response to BDE-99 indicated a positive, or potentially hermetic relationship with regards to the metabolic activity, warranting further investigation of underlying mechanisms.The final thesis chapter explores the unique potential of HuWaTERT for the generation of induced pluripotent stem cells (iPSCs). The main objective of this work was to generate a source of a number of different cell lines from the iPSCs, that could be applied for a more tailored approach to in-vitro chemical effect evaluation to fill the gap currently existing in the field of cetacean toxicology. The re-generation trial involved the use of the Sendai virus, which induces the de-differentiation mechanism in HuWaTERT to become iPSCs without integrating into the cell genome. After successfully generating a number of iPC colonies, the cells ultimately did not thrive, likely due to a fungal infection. Overall, this thesis combines both chemical exposure and effect assessment of novel chemical groups, for unique insight into chemical accumulation and impact in the Antarctic sea-ice ecosystem. The work provides new information regarding the range of chemicals that Antarctic consumers are exposed to, a reflection of hemispheric chemical usage and local input, and also contributes invaluable species-specific in vitro toxicity assessment data, which represents a critical research gap for cetacean chemical impact assessment.<br>Thesis (PhD Doctorate)<br>Doctor of Philosophy (PhD)<br>School of Environment and Sc<br>Science, Environment, Engineering and Technology<br>Full Text

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.

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.

The humpback whale was almost driven to extinction by commercial whaling in the Southern Ocean. Little is known about the degree of interchange among the remaining Southern Hemisphere populations. This thesis aimed to assess the connectivity among breeding grounds, feeding areas and migratory corridors of humpback whales using mitochondrial and nuclear DNA markers. The population structure of humpback whale populations in breeding grounds across the South Pacific and eastern Indian oceans was investigated, with an interest in the origins of whales in eastern Polynesia, using an extensive collection of mitochondrial DNA (mtDNA) sequences (n = 1,112; 470 base pairs in length). Samples were obtained from living whales at six breeding grounds: New Caledonia, Tonga, Cook Islands, French Polynesia (Society Islands), Colombia and western Australia. We found significant differentiation, at both the haplotype and nucleotide level, among the six breeding grounds (FST = 0.033; ΦST = 0.022) and for most pair-wise comparisons. The differentiation of the eastern Polynesia humpback whales is consistent with the hypothesis of a relic subpopulation, rather than vagrancy or colonization from known neighbouring breeding grounds. Regardless of their origin, it seems probable that islands of eastern Polynesia are now the primary breeding grounds for humpback whales feeding in the management Area VI (170°W – 120°W) of the Antarctic, as defined by the International Whaling Commission. A population of humpback whales migrates along the western South American coast, with breeding grounds mainly off Colombia and Ecuador and feeding areas off the western coast of the Antarctic Peninsula and in the channels and fjords ofsouthern Chile. We analysed the genetic relationship between humpback whales from these two summer feeding areas of the eastern South Pacific population to assess the potential heterogeneity in the migratory pattern of the population. We compared mitochondrial DNA control region sequences from 132 whales from the Antarctic Peninsula and 52 whales from the Magellan Strait areas. An AMOVA showed significant differences between the two feeding areas (FST = 0.180; ΦST = 0.169). A phylogenetic analysis showed both areas are represented in the AE clade that is only found in the Southern Hemisphere in the Colombian breeding ground. Genetic and previous demographic data (based on photo-identification) strongly suggest that both feeding areas are related to the same breeding ground but that heterogeneity exists among the feeding areas of this population, similar to that observed in the North Pacific and North Atlantic populations of humpback whales.Humpback whales migrating through eastern Australia and New Zealand have been linked with those breeding off northeastern Australia, New Caledonia, Fiji and Tonga, forming a single stock (Breeding Stock E). We investigated the relationship between the New Caledonian and Tongan breeding grounds, based on interchange of individual whales (genetically identified) and population genetic differentiation (mitochondrial DNA control region sequences and nuclear DNA microsatellites). We found significantly higher recapture probabilities within each breeding ground compared to the recapture probability between them using genetic identification, and significant differences at the population level in the FST and ΦST for mitochondrial and nuclear markers. These analyses suggest differentiation among the Breeding Stock E, supporting a proposed sub-stock division for New Caledonia (E2) and Tonga (E3). Historically, humpback whales off New Zealand coasts were caught during their migratory journeys between Antarctic feeding areas and tropical breeding grounds in the South Pacific. Here we investigated the genetic diversity of New Zealand humpback whales, comparing mitochondrial DNA control region sequence data with that from breeding grounds across the South Pacific (New Caledonia, Tonga, Cook Islands, French Polynesia and Colombia) and eastern Indian (western Australia) Oceans. We analyzed 30 samples collected around New Zealand, revealing 20 haplotypes. All haplotypes were found in New Caledonia and some were also found in other breeding grounds. New Zealand humpback whale haplotype diversity and nucleotide diversity were similar to those from the compared breeding grounds, but were significantly different at haplotype level from the Cook Islands, French Polynesia and Colombia breeding grounds. We found significant differences at haplotype level with the same three locations when a pair-wise AMOVA was performed. Three breeding grounds (western Australia, New Caledonia and Tonga) did not show significant differences at either nucleotide or haplotype levels. This genetic evidence and the available demographic data suggest a closer relationship of the New Zealand stock with New Caledonia and to a lesser extent with Tongan whales, supporting New Zealand as a primary migratory corridor for the humpback whales breeding in these western Pacific Islands.

Whales are mysterious and fascinating creatures. Despite modern technology, their world is still largely unexplored and unknown. They can only be seen, or rather glimpsed, when they are near the sea surface, either from boats, or perhaps from shore, or underwater by divers. They also reach astonishing sizes – the blue whale, for example, can grow to 30 metres in length, equivalent to the height of a six-storey building, and can weigh more than 130 tonnes.&#x0D; Seven ‘Great Whales’ are found in the coastal waters surrounding Australia. These include six of the largest baleen whales – blue whale, fin whale, humpback whale, sei whale, Bryde’s whale and southern right whale – and the sperm whale, the largest toothed whale. &#x0D; This book provides a detailed account of these extraordinary mammals. As well as the seven Great Whales, a smaller species – the minke whale – is included because of its special interest to Australians. The book describes whales’ highly specialised mammalian structure and biology, and the history of people’s association with them, at first through legend and wonder, then whaling, and more recently whale watching. It also looks at their past and current status, and the conservation initiatives that are in place to protect them from existing or potential threats.&#x0D; With both historical and recent photographs, as well as an extensive glossary, Great Whales will be enjoyed by natural history enthusiasts, zoologists and students alike.

Marine Mammals: Fisheries, Tourism and Management Issues brings together contributions from 68 leading scientists from 12 countries to provide a comprehensive, up-to-date review on the way we manage our interactions with whales, dolphins, seals and dugongs. The book examines how we have fared conserving the world’s marine mammal populations, with a focus on the key issues of fisheries and tourism.&#x0D; From a unique southern hemisphere perspective, the authors consider how science informs the culling debate, how wild fisheries and aquaculture interact with marine mammal populations and how we might manage the effects of whale, dolphin and seal watching industries. The authors also address other issues such as the way in which ethics, genetics, acoustics, ecosystem models and pollution influence the management and conservation of marine mammals.&#x0D; Marine Mammals is an invaluable and accessible resource for all those involved with marine mammals, including scientists, managers, policy makers, industry representatives and students.&#x0D; Winner of a 2004 Whitley Award.

The book combines the approaches of maritime history and ecological science to explore the evolution of life-forms and eco-systems in the ocean from a historical perspective, in order to establish and develop the sub-discipline of marine environmental history. Documentary records relating to the human activity, such as fishing, plus naturally occurring paleo-ecological data are analysed in order to determine the structure and function of exploited ecosystems. The book is divided into four chapter groups, the first concerned with Newfoundland and Grand Banks’ fisheries, the second with the potential of historical sources to provide a history of marine animal populations, the third explores the development of fisheries in the southern hemisphere during the twentieth century, and the final section explores the limitations of data and existing analysis of whale populations. The epilogue reiterates the suggestion that collaboration between historians and biologists is the key to furthering the sub-discipline.

In 1998, two species of minke whales were recognized based on the review of the morphological and genetic information available at that time: the Antarctic minke whale (Balaenoptera bonaerensis), which is restricted to the Southern Hemisphere, and the cosmopolitan common minke whale (Balaenoptera acutorostrata). Furthermore, three sub-species of the common minke whale were recognized: the North Atlantic (B. a. acutorostrata), North Pacific (B. a. scammoni) and Southern Hemisphere (B. a. subsp.). This chapter reviews the genetic studies on minke whales conducted after 1998. The review is organized by topic, e.g., those studies focused on phylogeny and other matters most relevant for taxonomy, and those focused on population genetic structure within oceanic basins most relevant for conservation and management. On the former topic, the new genetic information, whilst strongly supporting the minke whale taxonomic classification recognized in 1998, also reveals substantial genetic differentiation within the Southern Hemisphere common minke whales, with subsequent taxonomic implications. On the latter topic, results from different analytical procedures have provided information on population identification and structure in the Indo-Pacific sector of the Antarctic and western North Pacific, but they have failed to identify unequivocally any population within the North Atlantic common minke whales.