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| Author(s): |
Kátia Regina Groch
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD) |
| Defense date: | 2014-04-30 |
| Examining board members: |
José Luiz Catão Dias;
Artur Andriolo;
Jociery Einhardt Vergara Parente;
Ricardo de Francisco Strefezzi;
Leonardo Liberali Wedekin
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| Advisor: | José Luiz Catão Dias |
| Abstract | |
The exposure of humpback whales (Megaptera novaeangliae) to anthropogenic impacts is increasing due to population recovery following the legal ban on commercial whaling, together with the increment of human activities at the species breeding grounds and migration routes. However, little is known about the health and pathologic processes in humpback whales in Brazil. The present study investigated the health status of the population of humpback whales that seasonally migrate to the southeastern and northeastern Brazilian coast, aiming to identify possible lethal and nonlethal diseases, through histopathological analysis and study of osteopathies, as well as to quantify the occurrence of anthropogenic interactions, detrimental to the species. The evaluation was carried out through image analysis from photo-identified whales in the wild, during 5 years (2008-2012), through which skin lesions and scars were characterized, and anthropogenic, predatory or inter-specific marks were quantified. An estimate on individuals who survived to entanglement in fishing gear, collisions with vessels and/or interactions with predators was obtained. The investigation of pathologic processes in stranded animals performed by means of histopathological analysis of tissues from 19 animals found in good condition, while osteopathies were studied through macroscopic analysis on skeletal tissue of 49 necropsied animals. Immunohistochemical analysis was carried out in selected cases to search for Morbillivirus. The prevalence of skin lesions was estimated using a conservative, but systematic, approach and may be used as the basis for a long term assessment of the health status of this humpback whale population. Histopathological findings showed that most stranded calves had signs of perinatal or neonatal disorders, and are susceptible to infections. The study of skeletal lesions in stranded animals has shown that humpback whales are susceptible to degenerative, infectious and traumatic processes, and malformations. Finally, data obtained in this study present a first overview on health conditions and pathological processes in humpback whales in Brazil and may guide future studies in this area. By monitoring the occurrence of nonlethal lesions, as well as investigating pathological processes and causes of death of humpback whales, this study provides the environmental conditions in which these animals live and can contribute for the management and conservation actions for the species. (AU) | |