Veterinary pathology of stranded cetaceans in Canary Islands (06-12)

Abstract

The occurrence of disease in aquatic organisms will be probably one of the long-term consequences of climate change and environmental degradation. Cetaceans are regarded as sentinel species to monitor marine and marine-terrestrial interface ecosystems wherein humans are strictly integrated. Cetaceans are exposed to environmental stressors either anthropogenic, e.g., chemical and acoustic pollution, fisheries, maritime traffic, tourism industry, and non-anthropogenic, hereafter ‘natural,’ e.g., biotoxins, pathogens (bacteria, fungi, parasites, viruses). . Some of these pathogens have epizootic potential, are zoonotic or display complex pathogeneses in which biotic, e.g., genetic stock, immunologic dysfunction, and abiotic, e.g., chemical pollutants, may play a major role. This study describes the pathologic findings and most probable causes of death (CD) of 224 cetaceans stranded along the coastline of the Canary Islands (Spain) over a 7-year period, 2006–2012. Most probable CD, grouped as pathologic categories (PCs), was identified in 208/224 (92.8%) examined animals. Within natural PCs, those associated with good nutritional status represented 70/208 (33.6%), whereas, those associated with significant loss of nutritional status represented 49/208 (23.5%). Fatal intra- and interspecific traumatic interactions were 37/208 (17.8%). Vessel collisions included 24/208 (11.5%). Neonatal/perinatal pathology involved 13/208 (6.2%). Fatal interaction with fishing activities comprised 10/208 (4.8%). Within anthropogenic PCs, foreign body-associated pathology represented 5/208 (2.4%). A CD could not be determined in 16/208 (7.7%) cases. Natural PCs were dominated by infectious and parasitic disease processes. Herein, our results suggest that between 2006 and 2012, in the Canary Islands, direct human activity appeared responsible for 19% of cetaceans deaths, while natural pathologies accounted for 81%. These results, integrating novel findings and published reports, aid in delineating baseline knowledge on cetacean pathology and may be of value to rehabilitators, caregivers, diagnosticians and future conservation policies.