Franciscana (Pontoporia blainvillei) found dead in Northern Patagonia, Argentina: record, description and sampling. Preliminary report

Abstract

The Rio Negro estuary is considered the southernmost breeding and feeding area of the franciscana. Preliminary results of necropsies performed on six dead specimens found dead during 2020 are reported here. One calf, two juveniles/subadults and three adults were analyzed. Two of the adults died in gill nets. Macroparasites of Nematoda and Acantocephala phyla were found in the stomach inspections of four animals. Two dead specimens showed beak deviations which would represent the southernmost report of beak anomalies for the species throughout its range. Scattered granulomatous lesions compatible with mycobacteria was detected in one franciscana. Cultured samples of the whitish nodular lesions showed the development of acid-fast bacilli detection. In addition, molecular identification of Mycobacterium tuberculosis complex was positive. This report will be the first case of Mycobacterium tuberculosis complex in this cetacean. Based on the macroscopic lesions compatible with infectious diseases discovered here, it is necessary to extend the sanitary study of population of franciscana.