The North Pacific humpback whale (Megaptera novaeangliae) is a wide-ranging baleen whale species with a complex life history and population structure. As seasonal migrants, humpback whales are known to inhabit cooler, high-latitude waters when foraging and low-latitudes for mating and calving. Beyond this general migratory pattern, a number of demographic characteristics including, abundance, distribution, seasonal occurrence, and prey preferences remain unknown or poorly described. A complete understanding of humpback whale ecology is therefore lacking. Many methods used to explore these aspects of cetacean ecology are either prohibitively expensive or limited in the scope of what can be learned from their use. Fortunately, in recent years, the analysis of stable isotope ratios of animal tissues has proved a valuable and relatively inexpensive technique for providing information on trophic position, diet, and feeding origins of migratory populations. This study employed techniques in stable isotope ecology to increase knowledge of the population structure, migration routes, and foraging ecology of North Pacific humpback whales. Skin samples were collected from free-ranging humpback whales throughout all known feeding and breeding grounds and were analyzed for stable carbon ([delta]13C) and nitrogen ([delta]15N) isotope ratios. The population structure of humpback whales was first explored through geographic differences in stable isotope ratios. Stable isotope ratios varied significantly with location of sample collection. Based on this analysis, foraging animals were separated into six feeding groups. Classification tree analysis was then used to determine which isotopic variables could be used to predict group membership. Probable migratory linkages were then described by applying results of classification trees to [delta]13C and [delta]15N of animals sampled on breeding grounds. Strong migratory connections between the eastern-most foraging and breeding areas and the western-most areas were reflected in similarities of stable isotope ratios. Foraging ecology was then examined through calculation and comparison of the relative trophic levels of the six feeding groups. Isotopic values suggest some feeding groups are piscivorous, while others feed on a more mixed diet. These results can be used to determine if differences in diet composition between groups result in differences in accrued nutritional benefits, negatively impacting reproductive success and survival relative to fish eating groups. Finally, to gain insight into specific foraging habits, the diet of one group of humpback whales was modeled using an isotope mixing model. The [delta]13C and [delta]15N of Kodiak Island, Alaska humpback whales and several species of potential prey indicate that these animals likely rely heavily on euphausiids (Thysanoessa spinifera), Pacific sandlance (Ammodytes hexapterus), and capelin (Mallotus villosus). This study represents the first application of stable isotope ecology to an entire population of marine mammals. Stable isotope analysis was successfully applied to describe and improve understanding of the demographics of North Pacific humpback whales.

Whaling in the eighteenth and nineteenth centuries was a global industry. Ships from many nations with crews from ports all over the world hunted in waters from the Arctic Ocean to the Tasman Sea. Whale oil illuminated the cities and greased the machines of the Industrial Revolution. Far from formal legal institutions, the international cast of whalemen created their own rules and methods for resolving disputes at sea over the possession of a valuable natural resource. These unwritten customs were remarkably effective in preventing violence between crews of competing ships. Whaling was intensely competitive, yet the dangers of hunting in often treacherous conditions fostered a close knit community that was able to fashion resolutions to disagreements that also maximized their catch. Legal scholars have cited whaling customs as evidence that property law is often created by participants and not imposed by legislatures and courts. Whaling law was, in fact, a creation of both whalemen and lawyers. At sea, whalemen often improvised and compromised in ways that had more to do with personal and communal ethics than with well understood customs. Lawyers and judges, looking for certainty and consistency, imagined whaling customs to be much more established and universally observed than was ever the case. The same loose whaling customs that prevented violence and litigation failed, however, to check practices that severely depleted the available supply of bowhead and sperm whales. As a close knit community capable of governing themselves, American whalemen should have been able to find a way out of the "tragedy of the commons" which predicts that commonly owned and competitively exploited resources are - without an external or group imposed system of restraint - fated for destruction. Prior to about 1850, whalemen, generally believing that whales as a species were impervious to extinction, saw no need to limit their catch. By the time whalemen recognized that whales stocks were seriously depleted other sources of energy - coal oil and petroleum - had swept the market. There was, at this point, no reason to preserve the prey of a soon to be obsolete endeavor. / History

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No description available.

This study successfully utilised the non-invasive neuroimaging techniques of Computerised Tomography (CT) and Magnetic Resonance Imaging (MRI) to establish that dolphins have high relative brain size values, transcending the primate range for neocortex volume and neocortex ratio. Bottlenose dolphins superseded human values of the neocortex ratio and common dolphins marked the upper limit of the range for the dolphin species under investigation. In addition this study was the first to find a correlation between sociality and neocortex ratio in dolphins (R.I.M. Dunbar, pers.comm), which supports the hypothesis of neocortical development in relation to sociality/group size (Sawaguchi & Kudo 1990; Dunbar 1992) and social/Machiavellian intelligence (Byrne & Whiten 1988; Byrne 1995). The study devised new measures of relative brain size, including the grey-white matter and higher cortical ratios and these require further research before verification of their efficacy. Equations were calculated to allow estimation of: (1) MRI values of total brain volumes from CT values, (2) total brain volume from cranial volume using CT, (3) cerebral cortex volume from cranial or total brain volume (CT) and (4) cerebral cortex and cerebellar cortex volume from total brain volume (MRI). The effects of freezing and defrosting on volume and density of CT and MRI values were investigated. Additionally, the relationship between relative brain size (EQ) and sociality was investigated for other dolphin research, using previously published figures, but no significant correlations were found. Finally, dolphin values were compared to primate values for neocortex volume and neocortex ratio with the finding that the only primate within the dolphin range of neocortex was the human, positioned higher than the solitary humpback dolphin, but below all of the other, more socially complex, dolphin species. / Thesis (M.A.)-University of Natal, Durban, 1996.

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

This thesis analyzes two major discourses that intersect and inform one another in Witi Ihimaera's The whale rider: storytelling and modern science.

Submitted by (edna.saturno@ufrpe.br) on 2017-02-23T12:25:14Z No. of bitstreams: 1 Williams Dantas Charles.pdf: 2829415 bytes, checksum: bf5d0ed2319bb047d509bf6837ebad7e (MD5) / Made available in DSpace on 2017-02-23T12:25:14Z (GMT). No. of bitstreams: 1 Williams Dantas Charles.pdf: 2829415 bytes, checksum: bf5d0ed2319bb047d509bf6837ebad7e (MD5) Previous issue date: 2007-02-15 / Since 50`s, industrial fisheries have been damaged by cetaceans in all oceans, with different intensity levels. According to specialists, this behavior is named depredation, which occurs when the animals eat the fishes caught by a fishing gear. Killer whale has been cited as an animal that shows this kind of behavior often, otherwise other species as a false killer whale or sperm whale have been recorded doing fishing gear interactions. After the creation of the On Board Observers Program (PROBORDO) it was possible to cover all tuna fleet working in northeast of Brazil, based on Natal-RN, Cabedelo-PB and Recife-PE ports. The covering was made by board observers that get important information to the fisheries dynamic knowledge made by pelagic long line. Interactions between false killer whales and killer whales are cited as an important scientific subject, in relation to these fisheries type, that the present study pretends to show up. Factors like interactions type, groups’ size, qualitative and quantitative descriptions of depredated fishes and spatial location of the interactions were analyzed. The false killer whale showed greater occurrence on the study area than other species, generally within groups of few individuals, however, there were situations that the group was composed by hundreds of individuals. This species showed food preference about the target species of this fisheries kind, in other words, tuna and swordfishes instead of others catched, but in case of low productivity, they feed with squid used as a bait on the hooks. Killer whales were observed in the Tropical Western Atlantic, interacting with the fisheries. Also, there were accidental catches of the cited cetaceans by the fishing gear, what can bring serious damage to the individuals caughted. / Desde a década de 50, a indústria pesqueira vem sofrendo perdas provocadas por cetáceos, em todos os oceanos, com diferentes níveis de intensidade, num comportamento denominado pelos especialistas como depredação, que ocorre quando esses animais se alimentam do peixe capturado pela arte de pesca. Orcas verdadeiras têm sido citadas como as que exibem esse comportamento com maior freqüência, porém outras espécies como as falsas orcas e cachalotes, são registradas interagindo com a pesca. Com a criação do Programa de Observadores de Bordo (PROBORDO) foi possível a cobertura de toda a frota atuneira arrendada que opera no nordeste, sediada nos portos de Natal-RN, Cabedelo-PB e Recife-PE por observadores de bordo, que coletam informações relevantes para o conhecimento da dinâmica da pesca realizada com espinhel pelágico monofilamento. Dentre os assuntos de grande valor científico cita-se a ocorrência de interações entre as falsas orcas e as orcas verdadeiras, com esse tipo de pescaria, que o presente trabalho pretende apresentar. Fatores como o tipo de interação, tamanho de grupo, descrição quali-quantitativa dos peixes depredados e localização espacial das interações, foram analisados. A falsa orca apresentou maior ocorrência na área de estudo, geralmente em grupos de poucos indivíduos, porém houve situações em que o grupo era composto por centenas de espécimens. Elas demonstraram preferência alimentar pelas espécies-alvo deste tipo de pescaria, ou seja, atuns e espadartes em detrimento da fauna acompanhante, mas no caso de produtividade baixa, também se alimentavam das lulas, utilizadas nos anzóis como isca. Orcas verdadeiras também foram observadas na região do Atlântico oeste tropical, interagindo com a pesca. Também houveram capturas dos referidos cetáceos pelo espinhel, o que pode causar danos sérios aos espécimens capturados.

The biology of South African Bryde’s whales (Balaenoptera brydei/edeni), with a focus on the inshore form, was investigated through estimates of abundance and survival rate, seasonality of occurrence and variation in mitochondrial and nuclear DNA. Photographs, sightings data and biopsy samples were collected in Plettenberg Bay, on the south-east coast of South Africa. Additional genetic material was obtained from the Iziko South African Museum, Marine and Coastal Management, and the Port Elizabeth Museum. Mark-recapture methods applied to photo-identification data were used to estimate abundance and survival rate. Estimates of abundance ranged from 130 to 250 (CV = 0.07 - 0.38) and the estimated annual survival rate was 0.93 (CV = 0.047, 95% CI = 0.852 - 1.0). Seasonal increases in the encounter rate and number of individual whales were observed during summer and autumn, with a peak in April, which corresponded to increased feeding activity and larger average aggregation sizes. Chlorophyll-a, sea surface temperature and wind speed were all significant factors in explaining the variability in the occurrence of whales. No seasonality in the occurrence of calves was detected. Mitochondrial DNA control region sequences (685bp) were compared to published sequences. This confirmed the offshore form as Balaenoptera brydei and the inshore form as closely related to B.brydei, possibly at the sub-specific level, but excluded it as B.edeni. Phylogenetic analyses support complete separation between the two forms. The use of 10 polymorphic microsatellite loci revealed no population structure among the inshore samples (FST = 0.006). Pairwise estimates of relatedness found most individuals to be unrelated, with only a few distant relatives detected.

A perceived opposition between 'culture' and 'nature', presented as a dominant, biased and antagonistic relationship, is engrained in the language of Western culture. This opposition is reflected in, and adversely influences, our treatment of the ecosphere. I argue that through the study of literature, we can deconstruct this opposition and that such an ‘ecocritical’ operation is imperative if we are to avoid environmental catastrophe. I examine the way language influences our relationship with the world and trace the historical conception of ‘nature’ and its influence on the English language. The whale is, for many people, an important symbol of the natural world, and human interaction with these animals is an indication of our attitudes to the natural world in general. By focusing on whale texts (including older narratives, whaling books, novels and other whale-related texts), I explore the portrayal of whales and the natural world. Lastly, I suggest that Schopenhaurean thought, which has affinities in Moby-Dick, offers a cogent approach to ecocritically reading literature.