Rotta, Andrea (2009) Stato di benessere delle popolazioni di cetacei e marangone dal ciuffo nel nord Sardegna. Doctoral Thesis.
The aim of this research study was to assess the welfare of two endangered wildlife species inhabiting the coastal area of north east Sardinia, the Bottlenose dolphin (Tursiops truncatus) and the European shag (Phalacrocorax aristotelis desmarestii). In both cases, population size and interactions with human activities were evaluated in the waters within 3 miles from the coast of the would be ‘Bocche di Bonifacio’ International Park. Bottlenose dolphin population size was estimated in 96 individuals. Behavioural observations indicated a strong interaction between bottlenose dolphin and fisheries, mostly when trammel nets fishery targeting striped red mullet were used. Concentration of organo-chloride compounds in the bubbler of stranded animals evidenced that values are comparable to those found in small cetacean inhabiting Spanish coastal areas. The presence of morbillivirus infection among the population was detected. European shag breeding pairs in the studied area were 483 in 2007. Each pair raised a mean of 1.53 fledglings. Birds found entangled in fishing nets were mostly represented by adult males. Sex ratio was determined during two consecutive reproductive seasons by DNA analysis. Obtained data evidenced that, within fledglings, males accounted for the 60% of the population. This results suggest that feeding behaviour differed between sexes and that sex ratio was adjusted because of the high mortality of males in the fishing nets. This study demonstrated that the integration of data from different disciplinary activities can contribute to the identification of the principal threats affecting target species within a protected area. This information will represent a powerful toll in designing future conservation strategies.
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