Academic literature on the topic 'Long-finned pilot whales (Globicephala melas)'

Knowledge of animal morphometry is important to understanding their ecology. By attaching two parallel lasers to a camera, known as laser photogrammetry (LP), a scale is projected onto photographed animals, allowing measurement of their body. Our primary aims were to test LP precision, and to estimate body length from dorsal-fin dimensions of Globicephala melas. Secondary aims involved demonstrating applications of LP, such as sex and leader determination. Using photographs taken over two-months, we measured dorsal base lengths (DBL) of 194 individuals individually-identified with natural markings. Results indicated 33 individuals were photographed in multiple encounters and eight matched previously-sexed whales. A mean difference of <2.1% between DBL’s of 58% of repeatedly-sighted individuals was found, and whales closer to the boat (<22m) produced more precise measures. The length from the blowhole to anterior insertion of the dorsal fin (BAID) was a better predictor of total body length in stranded whales than DBL, and laser-estimated lengths fell almost all within known pilot whale size. Despite our small sample size, we showed two examples of how LP could be applied in research: (1) males and females had similar DBL (n=8), but large males could be distinguished using DBL; (2) leaders were not necessarily bigger than other individuals in the same cluster (n=4). The ease of use of LP makes it a valuable tool in collecting measurements of body features, especially when coupled with photo-identification. Keywords: laser photogrammetry, morphometrics, measurement, length, Globicephala melas

In general, mammal species show geographic or social dispersal by one or both sexes. Long-term behavioural observations and genetic evidence have confirmed that fish-eating resident killer whales, Orcinus orca, are a rare exception. Female and male offspring travel with their mothers for their whole lives: this is natal group philopatry. It is suspected that pilot whales, Globicephala spp., also follow this social pattern, but longitudinal data on the social structure of live long-finned pilot whales, Globicephala melas, are rare. We observed G. melas through July and August of 1998–2000 off northern Nova Scotia, Canada. Estimated group sizes ranged from 2 to 135 (mean = 20, SD = 17, median = 15, n = 249). We distinguished 322 individuals on the basis of distinctive marks on the dorsal fin, with estimated mark rates of 0.336 (proportion) (SE = 0.041) and 0.352 (mean of estimates) (SE = 0.036). Permutation testing rejected the null hypothesis of random association between individuals (p < 0.0005). The best fit model of the standardized lagged association rate suggests short-term associations of individuals over hours to days and long-term associations with a subset of those individuals over years. When scaled according to mark rate, sets of long-term associates average approximately 11–12 individuals, a much lower estimate than that presented previously from drive-fishery data from the Faroe Islands. Genetic sampling of behaviourally studied individuals is recommended.

Cetacean social structures include fluid and stable elements. Long-finned pilot whales (Globicephala melas) live in units that interact forming labile groups. In this study conducted off Cape Breton Island, between 1998–2011, we confirm unit membership predicts associations between individuals. We determine how units are structured and interact. We delineated 21 nearly-stable social units, with an average 7 members. For units where multiple individuals are sexed, both sexes are present. Most units showed long-term stability, while one showed evidence of splitting. Three units shared individuals with the largest unit (K, average size = 29). Splitting is likely triggered by size and difficulties maintaining associations between all individuals. Pilot whales face many pressures driving sociality at a range of temporal and social scales producing a multilevel society. While we have produced a more detailed model of long-finned pilot whale social structure, there are still unanswered questions, particularly whether units are strict matrilines.

Context Mass strandings of cetaceans occur frequently in Tasmania, Australia, with efforts made by authorities to rescue stranded animals when possible. Determining the fate of rescued cetaceans following a stranding event is essential to assess individual survival and the effectiveness of rescue procedures; however, few studies have monitored animals post-release and their fate remains largely unknown. Satellite telemetry of released cetaceans provides a means of assessing the short- to medium-term success of stranding management techniques. Aims To examine the short- to medium-term survival and at-sea movement and behaviour of long-finned pilot whales (Globicephala melas) on their release following a mass-stranding event. Methods We deployed satellite transmitters on 5 of 11 long-finned pilot whales returned to sea after a mass-stranding event in Tasmania in November 2008. The transmitters, incorporating a corrosive link, were attached to the dorsal fin of two adult and three subadult whales before release. The resulting telemetry data were examined to infer behaviour of the tagged individuals post-release, including swim speeds and how individuals moved in relation to each other over time. Key results Tracking data established the success of the rescue attempt and confirmed survival of stranded individuals in the short term (12–32 days) following release. Although conditions required whales to be released individually, data showed the tracked whales re-united immediately after release. A subsequent aerial survey revealed that they had formed a larger group with six additional whales which then separated and reformed. Conclusions Short-term survival of long-finned pilot whales following mass stranding and rescue was confirmed and behaviour was consistent with known behavioural information for this species. Importantly, the present study demonstrated physical recovery from a traumatic event in spite of delayed rescue and that individuals successfully re-united following individual release. Implications The present study confirmed that the rescue procedures employed were successful in the management and release of mass-stranded long-finned pilot whales, at least in the short term. It also provided some insight into the at-sea behaviour of this highly social and gregarious species and supported the theory behind stranding management techniques and the considerable resources and effort required for rescue of stranded cetaceans.

SUMMARYThe intestines of 170 long-finned pilot whales, Globicephala melas, caught off the Faroe Islands (N.E. Atlantic) were examined for helminth parasites. Eight species were detected but only 4 occurred in at least 10% of the sample. No core or recurrent group of species were identified and no correlations between abundances of species were significant. Diversity values were far below those reported for other endotherms. Colonization by helminths was random, whales not being readily colonized. These features point to largely unpredictable, isolationist infracommunities, there being little potential for inter-specific interactions. Older hosts tended to harbour more diverse infracommunities, offering more opportunities for such interactions. Two hypotheses, which might also apply to other cetaceans, are proposed to account for the depauperate helminth communities of the pilot whale: (i) some ancestral helminth species failed to adapt their cycles to the marine habitat and (ii) the hosts' isolation from land prohibited new infections with helminths of mammals.

In cooperation with an international research program concerning the biology of the long-finned pilot whale (Globicephala melas) in the Northeast Atlantic, 152 pilot whales taken in the Faroese drive fishery were examined for ectoparasites. The whale-louse Isocyamus delphini was detected on 45(29.61%) of the whales. Four whale groups were established, according to sex and sexual status: immature or pubertal males, mature males, immature females, and mature females. Whale-lice showed over-dispersed distributions on these four whale groups. Prevalence, abundance, and spatial distribution of I. delphini on sexually mature males were significantly different from those on the other whale classes. Heavy infections were only observed on mature males. Behavioral differences between males and females and between adults and juveniles could account for these results. The genital slit was by far the site most preferred by I. delphini. This location seems to be one of the few that offers appropriate shelter for this cyamid.

Selenium is an important nutritional element that is required in a minute amount for maintenance of proper health in both humans and animals. Many biochemical processes in human and animal depends on Se and selenoprotein function, and various studies have suggested that Se supplementation can improve fundamental immune function in both humans and animals. Se status in the UK is very low; therefore, there is a need to enhance selenium intake through diet. One way of doing that is through the introduction of selenium to farmed animals. In this Ph.D. study, we fed rainbow trout with diet containing different spiked concentrations (0.8 - 8.9 μg g-1) of Se for 14 weeks. Fish were sampled every two weeks and liver, kidney, muscle, gills and whole blood were collected and processed. The first phase of this Ph.D. study focused on selenium distribution and biotransformation in tissues of rainbow trout. Three methods were developed and used to determine total selenium concentration; species' distributions in tissues and Se peptide sequence to determine the possible incorporation of Se into proteins respectively. In the first method total selenium concentration was determined using ICP-MS and the second and third methods using HPLC-ICP-MS/ESI-MS. Total selenium concentrations in trout tissues were determined, and the highest selenium concentrations were found in liver followed by kidney, gills, and muscle. SeMet and SeCys were found to be the major species in all tissues followed by inorganic and other unknown species. To determine the possibility of Se incorporation in to protein, peptide de novo sequencing was carried out. Few selenoprotein were identified using automated de novo sequence and database search. Se species distributions in tissues of beached Pilot whales were studied. Several low molecular weights Se species were identified with selenite pre-dominating other species in most of the adult whales tissues analysed.

Short-finned pilot whales (Globicephala macrorhynchus) are the most frequently sighted odontocete in a long-term study in Hawaiʹi (representing 23.8% of all odontocete sightings from directed research efforts), yet little has been published on this species in Hawaiian waters. Studies elsewhere have suggested that short-finned pilot whales travel in stable mixed-sex groups composed of strongly associated individuals; however temporal analyses of social structure are lacking. To examine site fidelity, association patterns and temporal relationships, I analyzed data from 267 directed research and opportunistic encounters of short-finned pilot whales off the island of Hawai`i from 2003 through 2007. Sightings occurred year-round. Analysis of sighting depths in relation to effort indicated short-finned pilot whales are strongly associated with the island slope, with no sightings in water >2,700m deep despite effort to ~5,000m. Using only good quality photos, I identified 448 distinctive individuals; of these, 305 (68.1%) were seen more than once and 250 (55.8%) were seen in >1 year. Sighting histories varied from 1-29 sightings per individual (median=3) over the course of the study, suggesting only some individuals exhibit high site-fidelity. Degree of residency was assessed using multi-year site fidelity to the study area; individuals seen ≥5 times in ≥3 years were considered core residents (154 individuals) while individuals who fell below these criteria but that were seen more than once were termed residents (150 individuals) and those seen on a single occasion were termed visitors (142 individuals). Only 71.9% of the whales were linked by association into a single social network, suggesting the possibility of multiple populations using the study area. Individuals demonstrated preferential associations and community division was strongly supported by average-linkage hierarchical cluster analysis of the association data. Nine longitudinally-stable social units composed of key individuals (seen together ≥8 times in ≥4 years) and their constant companions (seen together ≥5 times in ≥3 years) were identified (unit membership 5-16, median=10.5; mean unit association index: 0.62-0.90). Qualitative assignment of age and sex classes to unit members indicated some segregation between adult males and female/calf pairs may occur. Temporal analysis using standardized lagged association rates of individuals grouped in the same encounter produced a best-fit model where dyads gradually disassociated over time while individuals grouped in the same day produced a model where dyads remained in association, suggesting companions not documented during an encounter are likely still present in the study area. Differential patterns of residency and site fidelity were unexpected and may be indicative of multiple populations around the main Hawaiian Islands. Additionally, the presence of a core resident population demonstrating strong, long-term site-fidelity and associations off the island of Hawaiʹi may warrant special management considerations. Evidence of fisheries-related injuries in addition to anthropogenic threats such as high levels of commercial and recreational vessel traffic, targeted tourist activities, and commercial and sports troll fisheries indicate that additional research is needed to evaluate potential threats to this island-associated population.

Tese de doutoramento em Ciências (ramo de conhecimento em Biologia)
This study focused mainly on providing information about the ecological and genetic characteristics of Iong-finned pilot whales (Globicephala meias) from the Western coast of the Iberian Peninsula, as weli as the determining the habitat preferences of this species, in that region. Additionally, the inclusion of samples from other regions ied to the investigation ofthe occurrence of population structure within the North Atiantic. Firstly, stomach contents and fatty acid analyses were used, to assess the dietary preferences and understand the influence of geographical and biological factors in the dietary ecoiogy of G. meias. Stomach contents results confirmed pilot whaies as mainly teuthophagous species and showed that Iberian whales had a more diverse diet, dominated by Octopodidae species, in comparison to the predominance of Ommastrephids in Scotland. The analysis of prey fatty acids, in the presnt study, also indicated that, although not conclusive, there is some evidence that iberian whales are feeding on octopods. Both stomach contents and fatty acid analyses reveaied the occurrence of significant geographical differences between animais from different regions of the North Atlantic (iberia, Scotland and USA). These results may be a consequence of the ingestion of different types of prey based on prey preference/availability or due to the exploitation of different feeding niches/habitats in the study areas, which suggest the possibiiity of the occurrence of different ecological groups with specific foraging habits in the North Atiantic. There were also biological influences on the dietary ecology of G. meias, particularly evident in the stomach contents analysis, where significant differences in the main prey consumed were associated with the Iength and sex of the animal. However, no significant differences occurred in the fatty acid profiles offemale/maie or mature/immature piiot whales. Secondly, the genetic population diversity and divergence of G. meias from six regions in the North Atlantic and adjacent waters were investigated, based on mitochondrial DNA (mtDNA) and MHC DRA and DOB loci. Both mtDNA and MHC diversities were comparabie to other abundant widespread cetaceans. Pairwise estimates of genetic differentiation (FST) indicated the occurrence of genetic structure at both regional and oceanic scaies at mtDNA, while MHC suggested that Iberian whaies represent a genetically differentiated group. Population structuring reveaied by mtDNA couid be reiated to the social structure presented by this species, associated with high leveis of female phylopatry. For the MHC loci, aithough the occurrence of historical balancing selection appeared to have an important role in shaping population diversity, the spatiai patterns of extnt diversity across the North Atlantic could be attributable to local selection pressures for specific pathogens/parasites or patterns of gene fiow and/or drift. Therefore, the combination of the results from ecological tracers (i.e. fatty acids, stomach contents) and genetic markers into a multi-tracer approach reveaied the occurrence of segregation oflong-finned piiot whaies from the different regions ofthe North Atlantic anaiysed. Furthermore, the resuits obtained in this thesis consistently show G. meias from the Western Iberian Peninsula as a potential different group within the North Atlantic, based on genetic (mtDNA and MHC) and trophi((stomach contents and fatty acids) analyses. Finally, since the identification of habitat preferences and suitable habitats within a species range has been defined as a priority for effective conservation and management, habitat modeling techniques (presence-only modeis, .i.e. PCA and Maxent) were used to determine piiot whales habitat preferences and suitabiiity in Atlantic Iberia, based on six ecogeographic variabies. Both methodologies identified depth and SST gradient as the most important variables for the ecological niche of pilot whales. SST was aiso an important variabie defined by PCA, aithough Maxent modei inciuded it as a variabie of minor importance. Higher habitat suitabiiity occurred in locations with shailower waters, higher values of SST gradient (aithough PCA, based on a shorter temporal scale, showed the opposite result for SST gradient) and SST values between 15 and 17°C. These resuits may indicate that pilot whales undertake incursions into coastal waters which may be related with a high concentration of Octopodidae spawners in these areas, in the upwelling season. However, it also highlights the importance of thinking carefully about the meaning of findings at different temporal scales, as weli as demonstrating the importance of using a fine temporal scale, in marine environments. The main results of this study contribute to the basic knowledge of this cetacean species, necessary for the determination of its conservation status and the identification of potential conservation concerns. In this context one ofthe key findings is the good evidence for existence of a separate Iberian population, which might be considered as a management unit for conservation purposes.
Este estudo focou-se na obtenção de informação sobre as características ecológicas e genéticas de Baleia-piloto (Globicephaia meias), bem como na determinação das preferências de habitat desta espécie, na Costa Oeste da Península Ibérica. Adicionalmente, foi também investigada a ocorrência de estrutura populacional no Atlântico Norte. Inicialmente, foram analisados conteúdos estomacais e ácidos gordos para determinar as preferências dietéticas e investigar a influência de factores geográficos e biológicos na ecologia trófica de G. meias. A análise de conteúdos estomacais confirma esta espécie como maioritariamente teutófaga, com as baleias Ibéricas a apresentarem uma dieta mais variada e dominada por Octopodidae, comparativamente com a predominância de Omastrephidae, na Escócia. A análise dos ácidos gordos de presas, no presente estudo, também sugere a possível ingestão de polvos por parte das bales que ocorrem na Península Ibérica. Os resultados dos conteúdos estomacais e dos perfis de ácidos gordos sugerem a ocorrência de diferenças geográficas significativas entre animais de diferentes regiões do Atlântico Norte (Península Ibérica, Escócia e EUA). Estas diferenças poderão resultar da ingestão de diferentes espécies-presa, consoante a preferência ou disponibilidade de presas ou da exploração de diferentes nichos/habitats na área de estudo, o que sugere a ocorrência de diferentes grupos ecológicos, com hábitos alimentares específicos no Atlântico Norte. Foram também observadas influências biológicas na ecologia alimentar de G. meias, principalmente ao nível dos conteúdos estomacais, onde a abundância das principais presas é significativamente influenciada pelo tamanho e sexo do predador. O mesmo não se verificou ao nível dos ácidos gordos, onde não ocorreram diferenças significativas entre machos/fêmeas ou entre animais imaturos/maturos. Em seguida, foram investigadas a diversidade genética e a estruturação populacional de G. meias de seis regiões do Atlântico Norte e águas adjacentes, baseados em AM mitocondrial (mtADN) e marcadores de MHC. A diversidade genética ao nível do mtADN e do MHC apresentou valores comparáveis com outras espécies de cetáceos. As estimativas de diferenciação genética (FST) indicam a ocorrência de estrutura populacional a escalas regionais e oceânicas para o mtADN, enquanto o MHC sugere as baleias da Península Ibérica como uma população geneticamente distinta. A estrutura populacional revelada pelo mtADN poderá estar relacionada com a estrutura social apresentada por esta espécie, com elevados níveis de filopatria feminina. Relativamente ao MHC, apesar de historicamente a selecção aparentar ser determinante para a diversidade genética, a estruturação espacial dessa mesma diversidade poderá ser atribuida a pressões selectivas locais por agentes patogénicos/parasitas específicos ou devido a padrões de fluxo e/ou deriva genética. Assim, a combinação de marcadores ecológicos e genéticos revelou a ocorrência de segregação de Baleias-piloto de diferentes regiões do Atlântico Norte. Adicionalmente, os resultados desta tese consistentemente sugeriram que as G. me/as da costa Oeste da P. Ibérica representam um grupo distinto no Atlântico Norte, baseado tanto em análises genéticas como tróficas. Por último, técnicas de modelação de haitat foram utilizadas (métodos de presença, PCA e Maxent) para determinar as características ambientais e os habitats favoráveis à ocorrência de Baleias-piloto na Costa Atlântica da Península Ibérica, tendo por base seis variáveis ambientais. Ambas as metodologias identificaram profundidade e gradiente de temperatura superficial da água (GrSST) como as variáveis que mais influenciaram a distribuição das baleias. A temperatura superficial da água (SST) foi também considerada uma variável importante pelo PCA, no entanto no modelo do Maxent foi incluída como uma variável de menor importância. As condições de habitat mais favoráveis para as baleias ocorreram em locais com águas menos profundas, valores elevados de GrSST (apesar de a utilização de uma escala temporal mais fina no PCA mostrar um resultado oposto para esta variável) e valores de SST entre 15 e 17°C. Estes resultados sugerem que as Baleias-piloto poderão realizar migrações para águas costeiras devido, provavelmente, à elevada concentração de indivíduos reprodutores de Octopodidae nessas águas, na época de afloramento. No entanto, também evidenciam a importância de uma cautelosa interpretação de resultados provenientes de diferentes escalas temporais e da utilização de escalas temporais finas, em ambientes marinhos. Os resultados do presente estudo contribuem para o conhecimento desta espécie, necessário para a determinação do seu estado de conservação e identificação de potenciais problemas de conservação. Dentro deste contexto, um dos principais resultados obtidos é a evidência da ocorrência de uma população distinta de G. meias na Península Ibérica, o que poderá constituir uma unidade de gestão independente, para fins de conservação.
Financial support for this investigation (SFRH/BD38735/2007, FCT and FSE - EU´s Third Community Support Framework) was received from Fundação para a Ciência e a Tecnologia e Ensino Superior. Financial support for part of the field work was received by SafaSea Project (Project 0039), supported by Iceland, Lichenstein and Norway through the EEA Financial Mechanism and by the MarPro (Project LIFE09 NAT/PT/000038), supported by a grant from Life+.