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Title: Population biology of bottlenose dolphins in the Azores archipelago
Author: Silva, Monica Almeida
ISNI:       0000 0004 2715 7876
Awarding Body: University of St Andrews
Current Institution: University of St Andrews
Date of Award: 2007
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The ranging behaviour, habitat preferences, genetic structure, and demographic parameters of bottlenose dolphins living in the Azores were studied using data collected from 1999 to 2004. Only 44 dolphins out of 966 identified were frequently sighted within and between years and showed strong site fidelity. The remaining individuals were either temporary migrants from within or outside the archipelago, or transients. Estimates of home range size were three times larger than previously reported for this species, possibly as a result of the lower availability of food resources. Mitochondrial DNA sequences showed very high gene and nucleotide diversity. There was no evidence of population structuring within the Azores. The Azorean population was not differentiated from the pelagic population of the Northwest Atlantic, suggesting the "unproductive" waters of the Atlantic do not constitute a barrier to dispersal. Population size, survival and temporary emigration rates were estimated using open-population models and Pollock's robust design. A few hundreds of dolphins occur in the area on a given year, though the majority should use it temporarily, as suggested by the high emigration rates. Bottlenose dolphins preferentially used shallow areas with high bottom relief. Temporal and spatial persistence of dolphin-habitat associations documented in this study further supports the idea of a close relationship between certain bathymetric features and important hydrographic processes and suggests the occurrence of prey aggregations over these areas may be, to some extent, predictable. Several results of this study suggest there are no reasons for concern about the status of this population. Yet, the resident group may be negatively affected by increasing pressure from the whale watching activity. Although the proposed Marine Park constitutes important habitat for resident dolphins, at present, the area is clearly insufficient to satisfy their spatial requirements and its conservation value may be limited.
Supervisor: Hammond, Philip S.; Santos, Ricardo Serrão Sponsor: Fundação para a Ciência e Tecnologia
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Cetaceans ; Bottlenose dolphins ; Photo-identification ; Ranging behaviour ; Capture-recapture methods ; Demographic parameters ; Habitat modelling ; Distribution ; Population structure ; Genetic structure ; Conservation ; QL737.C432S5 ; Bottlenose dolphin--Azores ; Bottlenose dolphin--Genetics--Azores ; Bottlenose dolphin--Conservation--Azores ; Cetacea populations--Azores ; Population biology