COMPARATIVE PATHOLOGY AND HEALTH EVALUATION OF BYCAUGHT FRANCISCANA DOLPHINS (Pontoporia blainvillei) FROM SÃO PAULO COAST, BRAZIL

• Grant number: 25/02136-4
• Support Opportunities: Scholarships in Brazil - Master
• Start date: June 01, 2025
• End date: August 31, 2026
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Pathology
• Principal Investigator: Jose Luiz Catao Dias
• Grantee: Barbara Sophia Leurizo Escrich Luques Codeas
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Franciscana dolphins (Pontoporia blainvillei) are small odontocetes that are endemic in the southwestern Atlantic Waters and inhabit coastal waters (<50m) off Brazil (itaúnas) to Argentina (Golfo Nuevo). According with the IUCN Red List of Threatened Species, they are classified as ''Vulnerable'' and as ''Critically Endangered'' according to the List of the Brazilian Fauna Threatened of Extinction, and thus, they are considered the most endangered dolphin in the Southwestern Atlantic Ocean, especially because the species is highly exposed to anthropogenic impacts such as bycatch. While post-mortem examination of stranded animals is a useful tool to assess bycatch and other anthropogenic impacts, there remains a lack of standardization concerning pathological findings of fishing-related deaths and its comorbidities in Franciscana, considering the diagnosis of drowning following underwater entrapment related with bycatch very challenging. Additionally, pathological investigation can also help to detect novel or emerging diseases, which is particularly relevant considering the escalating threats the marine ecosystem is facing linked with human exploitation and climate change, jeopardizing the long-term survival of the affected populations and, thus, directly influencing their conservation. Despite the conservation status of Franciscana dolphins, the available literature regarding infectious agents is extremely limited, mostly represented by bacteria, evidencing a gap of knowledge regarding its health evaluation. The main goals of this study is to describe the pathological lesions observed on bycaught Franciscana dolphins (planned sampling effort of 30 cases) , to establish diagnostic criteria of bycatch in this species, and investigate potential comorbidities and their etiological agents that may be affecting the health of bycaught individuals in the São Paulo coast, Brazil, by relying on classical (i.e., histopathology) and advanced (i.e., genetic and molecular) pathology tools, to infer about the health status of this critically threatened population. (AU)