Skeletal abnormalities in humpback whales Megaptera novaeangliae stranded in the Brazilian breeding ground

Skeletal tissues of 49 humpback whales Megaptera novaeangliae that stranded between 2002 and 2011 along the Abrolhos Bank seashore and its adjacent waters in Brazil were studied. Twelve (24.5%) animals presented pathological changes in one or more bones. Degenerative changes and developmental malformations were most frequent (10.2% each), followed by inflammatory/infectious and traumatic lesions (8.2% each). Infectious diseases led to severe lesions of the caudal vertebrae of 2 whales. In one of these individuals, the lesions involved 6 caudal vertebrae, leading to ankylosis of 3 vertebrae. Degenerative changes were observed in the vertebral columns of 3 animals, involving the joints of 13 ribs of 1 individual, and in the humerus of 1 whale. Traumatic lesions, such as osseous callus in the ribs, were observed in 4 animals. In 1 whale, the rib showed severe osteomyelitis, possibly resulting from the infection of multiple fractures. Developmental abnormalities such as spina bifida on 3 cervical vertebrae of 1 whale, fusion of spinal processes on thoracic vertebrae of 1 individual and fusion of the first 2 ribs unilaterally or bilaterally in 4 animals were found. Chronic infectious conditions found in the axial skeleton may have restrained spinal mobility and had detrimental effects on the general health of the animals, contributing to stranding and death. To our knowledge, this is the first systematic study on skeletal lesions in stranded humpback whales.

Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [2010/50094-3, 2011/08357-0, 2012/00021-5]

We thank Sr. Ariosvaldo Pinto dos Santos and volunteers for the invaluable support in the fieldwork; Projeto TAMAR, Parque Estadual de Itaúnas and Instituto Orca for the logistical support in many stranding events; Prof. Dr. Paulo César Simões-Lopes for providing many papers for the review of literature; Prof. Dr. Sentiel Rommel, Dr. Erwin J. O. Kompanje and 2 anonymous referees for very helpful comments on the manuscript; and Prof. Dr. Rainer Haetinger and Dr. Enio César Vieira Pereira for help with the interpretation of radiographic images. The support of Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), processes 2010/50094-3, 2011/ 08357-0 and 2012/00021-5, is greatly appreciated. Veracel Celulose provided financial support to the Rescue Program. Projeto Baleia Jubarte is sponsored by Petroleo Brasileiro (Petrobras). J.L.C.D. is a recipient of a pro fessorship by the Conselho Nacional de Desenvolvimen to Científico e Tecnológico— CNPq (301517/2006-1). This study was conducted by K.R.G. as partial fulfillment of the requirements for the doctoral degree at the Departamento de Patologia, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo.