The North Pacific humpback whale (Megaptera novaeangliae) population has been increasing at an average annual rate of ~6% since the early 1990s. In northern Southeast Alaska alone, there are now more whales than estimated for the entire North Pacific several decades ago. An understanding of how this growing population is repopulating traditional foraging grounds will benefit from detailed investigations of their prey preferences and trends in whale abundance and distribution relative to those prey. This dissertation examines these issues from late May until early September 2008 in Frederick Sound and Stephens Passage, a Southeast Alaskan feeding area historically used by humpback whales. The foundation for the study is an analysis of the life histories and abundance patterns of euphausiids, the principal prey of humpbacks in the area, during late spring and summer. Four species, Thysanoessa raschii, T. longipes, T. spinifera, and Euphausia pacifica, were identified in plankton net samples collected at random locations throughout the study site (n = 49) and in locations where a strong scattering layer was observed on a 120 kHz echosounder (n = 48). Both sample types varied in euphausiid species composition. Abundance patterns of immature euphausiids coupled with observations of females carrying spermatophores indicated differences between species in spawning schedules. Thysanoessa spp. began spawning in early April with the spring phytoplankton bloom and continued until late June, whereas E. pacifica began spawning in early June and continued until late August. This protracted recruitment of immature euphausiids was geographically widespread throughout the summer in contrast to adults, which, although present all summer, were found primarily in slope and shallow (< 100 m) areas. To determine if humpback whales preferred one euphausiid species or life-stage over another, net sample and hydroacoustic data collected in the vicinity of whales were compared to similar data collected in random locations throughout the study site. This revealed that whales targeted dense aggregations of adult euphausiids, but did not discriminate between the various species, which was surprising because of presumed differences in the energy density linked to their different spawning schedules. Additionally, whales did not spend time in areas with concentrations of immature euphausiids, which were likely not large enough during the study period to be suitable prey. With this preference for adult euphausiids, the abundance and distribution patterns of humpbacks were examined in relation to prey availability. Whale abundance was lowest at the beginning of the study in late May at ca. 68 whales and peaked in late July at ca. 228 animals – approximately 12% of the region’s estimated abundance for the study year. This study did not detect a concomitant increase in the availability of adult euphausiids, which is unsurprising since immature euphausiids would not recruit into the adult population until after the end of the study, and post-spawning mortality and predation pressure is presumably high during this time. Instead, whales clustered increasingly around comparatively fewer prey as the summer progressed. These observations, combined with a plateau in whale abundance after July, suggest that their abundance in the area was limited by euphausiid availability. Estimates of whales using the study site during the summer have remained similar over several decades despite a dramatic increase in humpback numbers in Southeast Alaska and elsewhere in the North Pacific. The results from this study suggest that, although the study site remains important seasonally to some whales, it is not a significant source of prey responsible for regional population growth in general. More likely, it is part of a network of feeding areas that has influenced the population trend. Further insight into these and the other issues raised in this dissertation could come from several additional analyses. An extended sampling season that captures the recruitment of immature euphausiids into the adult population would reveal whether a given year's prey cohort represents an important resource to whales in that same year, which has potential implications for interpreting mid-late season whale abundance patterns. As well, a photo-identification study would be useful in characterizing whale residency patterns and determining whether the abundance trends reflect a relatively small subset of the regional population using the area for most of the season or a continuous flow of a larger portion of the population. Finally, similar analyses as those outlined here but conducted in other areas within the region would provide additional insight into the network’s capacity to support the recovering whale population. / Graduation date: 2012

South Pacific humpback whales were devastated by commercial whaling in their Antarctic feeding areas during the 20th century. Understanding migratory connections and current abundance of these isolated breeding stocks is crucial for the allocation of historical Antarctic catches in population dynamic models used to assess current recovery. However, only a small number of migratory connections have been documented between Oceania breeding stocks within the South Pacific and feeding areas in the Antarctic. In addition, little is known about abundance of these stocks which encompass a vast oceanic region. For this thesis I first used mixed-stock analysis (MSA) to allocate migratory connections from four Antarctic feeding areas (n=142) to seven South Pacific breeding stocks (n=1,373), including four in Oceania, based on genetic marker frequencies. The use of this method was justified by the breeding stocks showing genetic differentiation at the haplotype level with an F[subscript ST] value of 0.027 (p-value <0.001). The results showed a relatively strong connection of Western Australia to Antarctic Area IV, Tonga to the border of Antarctic Area VI/I, Colombia to the Antarctic Peninsula, and a split allocation of Eastern Australia and New Caledonia to Antarctic Area V. This study provides the first population-level information supporting previous individual-based studies that humpback whale migration may not necessarily be direct north south. Next, utilizing capture-recapture methodology of unique humpback whale fluke photographs, I estimated abundance of one of the least studied Oceania breeding stocks, French Polynesia, a stock which also showed no significant migratory allocation using MSA. Taking into consideration the possible advantages of using Quality Control (QC) photographs to minimize bias in matching, estimates were generated using the complete photo catalogue and also using only photographs adhering to QC criteria. I found that the choice of using QC has an effect on the abundance generated and discuss the implications of this finding. Despite the photo catalogue used, the French Polynesia stock is estimated to number less than 1,900 individuals. Lastly, to provide additional information on the French Polynesia stock I used photo-identification to compare French Polynesia whales to whales in the Antarctic Peninsula and Strait of Magellan (Antarctic Area I), a possible migratory connection suggested by previous microsatellite genotyping. No conclusive matches were found. Although this does not discount the possibility of a few migrants traveling between these regions it does indicate the Antarctic Peninsula and the Strait of Magellan are not primary feeding areas of French Polynesia. This new information regarding abundance and migration of French Polynesia whales is important for the Comprehensive Assessment of Southern Hemisphere humpback whales. This document is currently being completed as the International Whaling Commission considers the next critical steps in recovery for Oceania humpback whales stocks. / Graduation date: 2010

Marine mammals are in a precarious conservation position because of anthropogenic impacts and historic perceptions that they are a consumable commodity. In light of changing abiotic conditions, further evaluation is needed on the habitat use, behavior, and interactions among marine mammals. Conservation legislation has helped protect species, but the greatest ground swelling may be the advent of the commercial whale watching industry. The feeding grounds in Alaskan waters have made this area a prime tourism location, and these nutrient-rich waters have resulted in a confluence of marine mammal species, including the appealing and abundant humpback whale (Megaptera novaeangliae) that may associate with three ecotypes of killer whales (Orcinus orca). These species are interesting because they may travel together to feed on prey or be adversaries in a predator-prey relationship. Using whale watching as a platform, this study evaluated the effects of the presence of these two species separately and together, and of the type of interaction between them, on human perception. Data were collected via opportunistic observations and a retrospective pre- and post-survey instrument. Differences in humpback whale distribution and group size patterns were found relative to killer whale occurrence, although humpback whale behavioral states were unchanged. Changes in passenger conservation attitudes could not be attributed to species and behaviors but they were important determinates to whale watching satisfaction. Overall, more positive conservation attitudes and an increase in knowledge about marine mammals were reported after whale watching. These tours provide an opportunity for collecting meaningful scientific data and providing more in-depth education such as enhancing the appreciation for ecosystem services provided by marine mammals.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2004. / Includes bibliographical references.

Population structure and vital rates of Gulf of Maine (GOM) humpback whales, Megaptera novaeangliae, were studied by a combination of longitudinal data, region-wide surveys and modern mark-recapture statistical methods. Demography and rates of exchange were examined among six GOM areas. Juveniles and females were preferentially encountered in southern GOM habitats, including at the Studds Stellwagen Bank National Marine Sanctuary (SBNMS). Multi-state modelling also revealed unequal probabilities of movement between areas that was not explained by inter-area distance, adjacency, whale density or dominant prey type. Aerial surveys and photo-identification data indicated that the population was likely closed to migration between June and September. Otherwise, seasonal trends in population composition were consistent the demographically staggered migration reported in other oceans. Over-wintering occurred,but there was little evidence that a significant number of humpback whales failed to undertake or complete migration each year. Vital rates varied with sex, age and time. Juveniles exhibited lower and more variable survival than adults and so were a potential source of downward bias in “non-calf” survival estimates. Males exhibited higher survival than females and achieved maximal survival at age five, the estimated age at male puberty. By contrast, females did not reach peak survival until the current average age at first birth (8.78 years, s = 2.33). The latter was significantly higher than previous estimates and females that recruited by age seven had a lower likelihood of subsequent survival than those that recruited late. Costs of reproduction persisted into adulthood, with breeders exhibiting lower survival than nonbreeders. Calves born during years of low fecundity exhibited lower survival than those born when fecundity was high, possibly due to lower maternal investment. Costs of reproduction have not previously been described in cetaceans, but are consistent with the risks potentially associated with capital breeding.

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.

A fim de caracterizar o comportamento de filhotes de baleia jubarte, este estudo foi conduzido ao redor do Arquipélago dos Abrolhos, um importante sítio de nascimento e cria da espécie no Brasil. Foram investigados aspectos do desenvolvimento comportamental dos filhotes, diferenças comportamentais entre filhotes nascidos em diferentes temporadas reprodutivas e, também, a influência da presença de um escorte no comportamento dos filhotes. Os dados foram coletados entre os anos de 1998 a 2004, entre os meses de julho a novembro, a partir de um ponto fixo de observação no topo da Ilha de Santa Bárbara, no Arquipélago dos Abrolhos. O método utilizado foi o de amostragem de animal focal, com registro de todos os eventos e estados comportamentais realizados pelos filhotes, com o auxilio de um teodolito. 207 observações focais foram analisadas, totalizando 313,65 horas de amostragem. Os filhotes apresentaram um repertório comportamental bastante diverso e com uma grande variação quanto à taxa de ocorrência. Os eventos mais freqüentes foram ARQUEAMENTO DO PEDÚNCULO, SALTO, EXPOSIÇÃO DE UM LOBO DA CAUDAL e BATIDA DE CAUDAL; os poucos freqüentes ou raros foram SLASH DE CAUDAL, BARRIGA PARA CIMA, ACENANDO e ALONGAMENTO DO PEDÚNCULO. Entre os estados comportamentais, os filhotes permaneceram a maior parte do tempo em NATAÇÃO, sendo observado em média 42,21% do tempo. MILLING foi o segundo estado mais freqüente (média: 29,86%), seguido de REPOUSO (média: 20,91%) e ATIVO (média: 7,02%). A alta freqüência de ocorrência de alguns eventos e o tempo gasto em NATAÇÃO sugerem a importância desses comportamentos no desenvolvimento da coordenação e aptidão motora, fortalecimento da musculatura e melhora da resistência nos filhotes. Dessa maneira, os filhotes desenvolvem habilidades necessárias para interações sociais futuras e reprodução e, também, para necessidades do momento, como o desenvolvimento da relação com a mãe, amamentação e preparação para a migração. A análise do comportamento dos filhotes nas três fases da temporada reprodutiva mostrou que os filhotes aumentaram a taxa de ocorrência dos eventos ARQUEAMENTO DO PEDÚNCULO, EXPOSIÇÃO DE CABEÇA, BATIDA DE CABEÇA, EXPOSIÇÃO DE UM LOBO DA CAUDAL e EXPOSIÇÃO DE PEITORAL. Entretanto, não foi possível identificar estágios de desenvolvimento específicos. Dez dos 18 eventos comportamentais apresentaram diferenças na taxa de ocorrência entre filhotes de temporadas distintas, assim como a proporção do tempo gasto em REPOUSO pelos filhotes foi diferente. Apesar destas diferenças observadas entre alguns anos, não foi identificado um padrão temporal. Na presença de um escorte o comportamento dos filhotes mudou: a taxa de ocorrência de ARQUEAMENTO DO PEDÚNCULO, EXPOSIÇÃO DE CABEÇA e COLO foi significativamente menor. Adicionalmente, os filhotes permaneceram mais tempo em NATAÇÃO e menos tempo em REPOUSO do que quando estavam acompanhados apenas de suas mães. Alguns trabalhos sugerem que a presença de um escorte pode proporcionar proteção ao filhote, porém, diante das alterações comportamentais observadas, e do aumento da velocidade média de natação, a presença do escorte parece não trazer benefícios, pelo contrário, parece ter um efeito negativo para o filhote, ao menos em termos energéticos. / To characterize the behavior of humpback whales calves, a study was conduct around Abrolhos Archipelago, an important nursing area for the species in Brazil. It was investigated aspects of the behavioral development of calves, behavioral differences between calves of different breeding seasons and also the effects of the presence of one escort in the behavior of calves. The data were collected from 1998 to 2004, through the months of July to November, from a land-base station on the top of Santa Barbara Island at the Abrolhos Archipelago. The chosen method was animal focal sampling, with record of all behavioral events and state occurrences, using a theodolite. A total of 207 focal observations were analyzed, comprising 313.65 hours of sampling. Humpback whales calves exhibit a very diverse behavioral repertoire, with a strong variation in the occurrence rate. More frequent events were PEDUNCLE ARCH, BREACH, EXPOSITION OF HALF OF THE FLUKE and TAIL SLAP; and the less frequent were TAIL SLASH, BELLY-UP, TAIL WAVE and PEDUNCLE ELONGATION. Among the behavioral states, calves remained more time SWIMMING (mean: 42.21%). MILLING was the second most frequent state (mean: 29.86%), followed by RESTING (mean: 20.91%) and ACTIVE was the least frequent (mean: 7.02%). The high frequency of occurrence of some behavioral events as well as the high proportion of time SWIMMING suggest that these behaviors are important to the development of coordination and motor ability and also to muscle strengthening. In this way, the calves can develop abilities needed to future social interactions and reproduction, but also to current needs, as in the development of the relationship with its mother, for nursing and for preparing to migration. There was a significant effect of phase of the season on rate of occurrence of PEDUNCLE ARCH, HEAD EXPOSITION, HEAD SLAP, EXPOSITION OF HALF OF THE FLUKE and PECTORAL EXPOSITION. However it was not possible to identify a specific development stage. Ten of 18 behavioral events showed variation in the rate of occurrence along the seven breeding seasons studied, also the proportion of time RESTING state showed a significant difference among seasons. Despite the observed differences among some years, they did not show any pattern. In the presence of one escort the behavior of calves changed. The rate of occurrence of PEDUNCLE ARCH, HEAD EXPOSITION and LAP was significant lower. Besides, calves remained more time SWIMMING and less time RESTING than when calves were only accompanied with their mothers. Studies suggest distinct functions to escorts, including provide protection to calves. However in face of the behavioral changes and increase in speed of swimming, the presence of one escort seems not to be an advantage, on the contrary seems to have a negative effect to the calf, at least in the energetic demand.

Developing appropriate management plans for species at risk requires information about their population structure and abundance. For most cetacean populations, few reliable population estimates are available and even fewer distributions have been mapped. Accurate abundance estimates can be determined from capture-recapture data if assumptions are met, however this can be difficult when the animal in question demonstrates both strong site fidelity and large-scale migrations, and different models can result in dramatically different results. I explored these issues by examining a 15-year dataset (1992-2006) of photo-identifications of humpback whales (Megaptera novaeangliae) in British Columbia (BC), Canada. I used multiple capture-recapture models to compare how the definition of population and variation in effort affected estimates of population size, and I explored means to correct for these biases. I also considered stock structure by examining individual breeding ground destinations, movement, and localized site-fidelity within BC. Across the six models considered, the BC humpback whale abundance in 2006 ranged between 1,428 and 3,856 individuals. The Lincoln-Petersen estimate (1,428-1,892) likely best described the number of humpback whales in BC during summer 2006. The effort-standardized Jolly-Seber model (1,970-2,331) is more representative of the larger population of humpback whales that uses or passes through BC over multiple years. Ultimately, selecting the best estimation model requires defining the ‘population’ of interest and accounting for spatial and temporal distribution of sampling effort. British Columbia provides feeding habitat and a potential migratory corridor for whales that breed in the northeastern Pacific Ocean. Forty-four percent of the 1,986 humpback whales considered were sighted in BC in more than one year. Identifications were highest from May to October, with a peak in September, but humpback whales were present in BC in all months of the year. Whales showed strong site fidelity with a median re-sighting distance of 75 km between years, and a maximum re-sighting distance that ranged from 0.41 km to 842 km. Matching rate within BC decreased as a function of north-south distance, though no clear north-south boundary could be established. Stock structure of humpback whales in British Columbia is complex and should be considered in managing this population.

Developing appropriate management plans for species at risk requires information about their population structure and abundance. For most cetacean populations, few reliable population estimates are available and even fewer distributions have been mapped. Accurate abundance estimates can be determined from capture-recapture data if assumptions are met, however this can be difficult when the animal in question demonstrates both strong site fidelity and large-scale migrations, and different models can result in dramatically different results. I explored these issues by examining a 15-year dataset (1992-2006) of photo-identifications of humpback whales (Megaptera novaeangliae) in British Columbia (BC), Canada. I used multiple capture-recapture models to compare how the definition of population and variation in effort affected estimates of population size, and I explored means to correct for these biases. I also considered stock structure by examining individual breeding ground destinations, movement, and localized site-fidelity within BC. Across the six models considered, the BC humpback whale abundance in 2006 ranged between 1,428 and 3,856 individuals. The Lincoln-Petersen estimate (1,428-1,892) likely best described the number of humpback whales in BC during summer 2006. The effort-standardized Jolly-Seber model (1,970-2,331) is more representative of the larger population of humpback whales that uses or passes through BC over multiple years. Ultimately, selecting the best estimation model requires defining the ‘population’ of interest and accounting for spatial and temporal distribution of sampling effort. British Columbia provides feeding habitat and a potential migratory corridor for whales that breed in the northeastern Pacific Ocean. Forty-four percent of the 1,986 humpback whales considered were sighted in BC in more than one year. Identifications were highest from May to October, with a peak in September, but humpback whales were present in BC in all months of the year. Whales showed strong site fidelity with a median re-sighting distance of 75 km between years, and a maximum re-sighting distance that ranged from 0.41 km to 842 km. Matching rate within BC decreased as a function of north-south distance, though no clear north-south boundary could be established. Stock structure of humpback whales in British Columbia is complex and should be considered in managing this population.

<p>High-resolution bio-logging tools were used to examine the fine-scale foraging behaviors of humpback whales (Megaptera novaeangliae) in the coastal waters of the Western Antarctic Peninsula during the austral autumn of 2009 and 2010. Discrete feeding events (i.e., lunges) were inferred from the biologging records of thirteen whales, including a mother and her calf. In general, humpback whales exhibited efficient foraging behaviors that allowed them to maximize energetic gains and minimize energetic costs as predicted by optimal foraging theory. They fed at a continuous and high rate in the upper portion of the water column (< 100 m) from approximately dusk to dawn when their prey (Antarctic krill, Euphausia superba) were most vulnerable and less costly to acquire (i.e., near the surface). When forced to dive to greater depths, they adjusted their behaviors (e.g., descent and ascent rates) so that they could maximize their foraging durations and increase their lunging rates. In addition, humpbacks appeared to accept short term (i.e., dive by dive) costs associated with depleted oxygen stores in favor of maximizing long term (i.e., daily) energetic gains. Such efficient behaviors are particularly beneficial for mother-calf pairs who have additional energetic costs associated with foraging, such as lactation (mother), growth (calf), and maintaining proximity. In addition, because the physiology of humpback whales is poorly understood yet critically important for predicting their behaviors in response to fluctuations in their environmental conditions, foraging behaviors inferred from the bio-logging records were used to estimate their metabolic rates, oxygen storage capacities, and oxygen replenishment rates under the framework of optimal foraging theory. This research suggests that the current techniques used to estimate humpback whale oxygen stores is appropriate but that the estimation of metabolic rates of humpbacks while foraging and while traveling need to be addressed further. This work aims to increase the current understanding of humpback whale foraging behaviors along the Western Antarctic Peninsula so that appropriate measures can be taken to aid in their recovery and in the sustainability of the Antarctic marine ecosystem.</p> / Dissertation