Thesis (Ph. D.)--University of Adelaide, 1984. / Includes bibliographical references (leaves 193-224).

Bibliography: leaves 193-224.

Le lion de mer Australien a un cycle de reproduction non-annuel et asynchrone entre les colonies.Contrairement aux autres pinnipèdes, ce système unique offre l’opportunité aux mâles de se reproduiredans plusieurs sites lors d’une saison de reproduction. L’accès des mâles à plusieurs sites dereproduction pourrait contrecarrer le fort degré de structure génétique de population chez les femellesdûe à une fidélité extrême au site de reproduction. J'ai utilisé deux méthodes indépendantes maiscomplémentaires, moléculaire et acoustique, afin d’étudier la structure de la population et le systèmede reproduction. Pour l'analyse moléculaire, j'ai développé une banque de microsatellites spécifiques àl'espèce. Ces marqueurs ont été utilisés pour examiner le flux génétique des mâles dans les différentescolonies de reproduction, le succès reproducteur, et les taux de paternité inter- et intra-colonies. Deplus, j'ai mesuré la variation géographique dans les cris des mâles, ce qui représente une approchealternative pour mesurer les convergences/divergences entre colonies. J'ai montré que si les mâlesprésentent une certaine dispersion entre colonies, elle est limitée à une courte échelle en dépit del’opportunité des mâles de se reproduire dans différents sites. Les analyses acoustiques des cris demâles ont révélé des variations géographiques significatives entre colonies, qui ne reflètent pas lastructure génétique. Les analyses de paternité indiquent un faible taux de polygynie, la majorité desmâles ne produisant qu’un ou deux jeunes par saison. Des stratégies alternatives de reproduction(nomade ou sédentaire) sont présentes dans cette espèce, certains mâles se déplaçant activement entredifférentes colonies proches. Le système de reproduction unique du lion de mer Australien semblefortement influer à la fois les modalités de dispersion, mais aussi la structure de population et lesystème de reproduction. / The Australian sea lion has a non-annual and asynchronous breeding cycle across geographically closecolonies. In contrast to other pinnipeds, this unique reproductive system provides the opportunity formales to breed in different colonies during one breeding cycle. Male mating success across differentcolonies could counteract the high degree of structure driven by extreme site fidelity in females. I usedtwo, independent but complementary methods, molecular and acoustic to investigate their populationstructure and mating system. For molecular analysis I developed a species-specific microsatellitelibrary. These markers were used to examine the extent and rate of male mediated gene-flow acrossbreeding colonies but also to determine the breeding success and paternity both within and acrossspatially close colonies. Also, I investigated the geographical variation in male barking call. Thisrepresents an alternative approach to measure boundaries and relationships between colonies. Malesexhibit dispersal; however, this is limited to remarkably small scale in regards to the high potential fordispersal and opportunity to breed in different colonies. Acoustic analyses of the male barking callsrevealed significant geographical variation across sites; however this observed acoustic variation didnot reflect the genetic structure. Paternity analyses revealed that males display relatively modest ratesof polygyny with the majority of successful males siring only one or two pups per breeding cycle. Thepresence of alternative mating strategies (roaming vs staying) is apparent in this species with somemales actively moving and breeding between close colonies. It appears that the unique breedingbiology of Australian sea lion influences dispersal patterns, population structure and mating system.

Bibliography: leaves 193-224 / xvi, 224 leaves, [1] plate : ill. (1 col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Pathology, 1984

Over the last 15 years, pinniped tourism has experienced a rapid growth in the Southern Hemisphere, and particularly in Australia and New Zealand where at least four sites attract more than 100,000 visitors per year. Tourism focused on the Australian sea lion (Neophoca cinerea), a protected species endemic to Australia, occurs in at least nine sites in South Australia and Western Australia. Australian sea lions haul out on several offshore islands in the Perth region. Carnac Island Nature Reserve is one of the main sites where people can view sea lions near Perth, either during recreational activities or on commercial tours. This study sought: (1) to investigate the potential impact of human visitors on Australian sea lions hauled out on Carnac Island, (2) to consider implications of the results for the management of Carnac Island Nature Reserve, and (3) to examine under which conditions tourism and recreation around sea lions can be sustained in the long term. Sea lion numbers, rate of return to the site, behavioural response to human presence and incidents of disturbances of sea lions by visitors were recorded over a period of four months on Carnac Island. A survey of 207 visitors was also carried out. Findings indicated that there were two main types of human impacts on the sea lions: • A specific state of sea lion vigilance induced by low level, but ongoing, repetitive disturbances from human presence, sustained at various approach distances ranging to more than 15 m, vigilance that is different from the behaviour profile observed in the absence of human disturbance, • Impacts resulting from incidental direct disturbances of sea lions by visitors from inappropriate human recreational activities or from visitors trying to elicit a more ‘active’ sea lion response than the usual ‘sleeping or resting’ behaviour on display; these impacts included sea lions retreating and leaving the beach, or displaying aggressive behaviour. Impacts on sea lions from these disturbances may range from a potential sea lion physiological stress response to sea lions leaving the beach, a reduction in the time sea lions spend hauling out, and, in the longer term, the risk of sea lions abandoning the site altogether. Repeated instances of visitors (including unsupervised young children) approaching sea lions at very short distances of less than 2.5 m represented a public safety risk. Results also indicated that (1) the numbers of sea lions hauled out and their rate of return to the beach did not appear to be affected by an increase in the level of human visitation (although longer-term studies would be required to confirm this result); and (2) there appeared to be a high turnover rate of sea lions at the site from day to day, suggesting that there are frequent arrivals and departures of sea lions to and from Carnac Island. The visitor survey indicated that many visitors to Carnac Island had a recreational focus that was not primarily directed towards sea lion viewing (‘incidental ecotourists’). Although many visitors witnessed incidental disturbance caused by humans to sea lions, they did not seem to recognise that they themselves could disturb sea lions through their mere presence. Visitors also seemed to have a limited awareness of the safety risk posed by sea lions at close range. Visitors expressed support for the presence of a volunteer ranger on the beach and for more on-site information about sea lions. Finally, visitors indicated that they greatly valued their sea lion viewing experience. It is anticipated that the continued increase in visitation to Carnac Island from recreation and from tourism will result in intensified competition for space between humans and sea lions. Long-term impacts of human disturbances on sea lions are unknown, but a physiological stress response and/or the abandonment of haulout sites has been observed in other pinniped species. The findings of this study highlight the need to implement a long-term strategy to reduce disturbance levels of sea lions by visitors at Carnac Island to ensure that tourism and recreation around sea lions can be sustained in the long term. Recommendations include measures to control visitor numbers on the island through an equitable allocation system between various user groups, the development of on-site sea lion interpretation and a public education and awareness program, the setting up of a Sea Lion Sanctuary Zone on the main beach, ongoing monitoring of sea lion and visitor numbers and other data, and a system of training and accreditation of guides employed by tour operators.