La pathologie en pisciculture tropicale et l'approche écopathologique : méthodologie et étude de cas sur les élevages de Pangasiidae

Abstract

The profound changes in breeding and rearing systems along with the intensification of tropical aquaculture production, especially in South-East Asia, tend to increase the occurrence of epizooties and enzootic diseases, of which the socio-economic and environmental impacts amount to hundreds of millions of US $ per year. Because of the variety of cultured species and culture environments, diseases are numerous and their natures are generally multi-factorial, thus complicating health management. Until now, Asian fish-culturists have explored exclusively or essentially the chemotherapeutic register, which is known to result in the accumulation of residues in the environment and/or fish flesh, and to promote antibiotic resistance, including through the transfer of resistance between bacterial species. Alternatives to this chemical strategy are urgently needed to secure the health management of cultured fish, in particular in the field of epidemiology and ecopathology. Ecopathology is a branch of analytical epidemiology that explores and analyzes the different variables of an animal production system in order to individualize the risk factors responsible for creating the setting of a pathogen or disease breakthrough. This holistic approach, which regards pathology as one of the outcomes of a productive system, is very rarely used in aquaculture. This article provides a synthesis on the health issues of fish breeding systems in the tropics, with emphasis on South East Asia, and illustrates the benefits of an ecopathological strategy that was deployed to elucidate then alleviate the mortality of Pangasius spp. reared in floating cages in the Mekong River, Vietnam.