The prevalence of epidermal conditions in a small population of coastal bottlenose dolphins (Tursiops truncatus) in Monterey Bay was evaluated between 2006 and 2008. Five different skin condition categories were considered, including Pox-Like Lesions, Discoloration, Orange Film, Polygon Lesions, and Miscellaneous Markings. Of 147 adults and 42 calves photographically examined, at least 90 and 71%, respectively, were affected by at least one or multiple conditions. Pox-Like Lesions were the most prevalent, affecting 80% of the population, including adults and calves. This condition warrants the most urgent investigation being possibly indicative of the widespread presence of poxvirus or a similar pathogen in the population. In view of the high number of individuals affected, standard monitoring of the health status of Monterey Bay bottlenose dolphins is considered imperative. Discoloration was strongly associated with Pox-Like lesions. Orange Films were likely an epifaunal infestation caused by diatoms, which have been documented in other cetacean species. Polygon Lesions, a newly described category, could be the result of infestation by barnacles of the genus Cryptolepas. Miscellaneous Markings were variable in appearance and may not have the same causative factor. Although none of the proposed etiologies can be confirmed without appropriate clinical tests, recognizing common visible characteristics of the conditions could aid in preliminary comparisons across populations and individuals.
hundreds of thousands of individuals (Read et al. 2006). Most types of fishing gear (e.g. gillnets, long lines, and pot/trap lines) are known to cause entanglements (
Short-term measures of behavioural responses of cetaceans to tourism operations have been used in many studies to interpret and understand potential long-term impacts of biological importance. The short-beaked common dolphin (Delphinus delphis) is the species most frequently observed in the Azores and constitutes an important component of the marine mammal tourism industry in this region. This study investigated the potential effects of tour boats on the behaviour of common dolphins off São Miguel, Azores, with particular focus on the changes in activity budget and the time required to resume activities after a tour boat interaction. Behavioural data were collected from land using a group focal-follow methodology. Markov chains were applied to analyse control and interaction sequences and to assess behavioural transition probabilities in both scenarios. In the presence of tour boats, dolphins significantly reduced the time spent foraging and increased the time engaged in other high energy activities. Dolphins also took significantly longer to resume feeding after an interaction occurred. The average bout length varied significantly between control and interaction scenarios, with foraging bouts being shorter during tour boats interactions. The results presented have management implications since feeding is a biologically critical activity. Disruption of foraging behaviour could lead to a decrease in energy intake for this population. With cetacean tourism likely to increase in the future, a precautionary approach to issuing new licences is advisable and any expansion would warrant an appropriate monitoring programme.
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