First Map of Diseases that Affect Decorative Fish in Colombia
By: Giovanni Clavijo Figueroa,, Unimedios
The use of fish for decorative purposes dates as far back as ancient Babylonia −around the fifth century B.C.−, and currently in certain cultures such as in Asia, these aquatic animals are a sign of socioeconomic status.
In South America, extracting fish from their habitats is a highly profitable activity, which leads to a dilemma: on the one hand, it is one of the few legal employment options in many riverside and jungle regions of Colombia, while on the other hand it causes an ecological impact that has yet to be adequately measured.
In the Colombian case, the rivers from which decorative fish species are taken are mostly found in the Orinoco and Amazon basins. Their exportation generates revenues of around US$ 8 million yearly. According to UN Comtrade 2010 data, Colombia is one of Latin America's leading countries in this trade (holding first place in the value of exports and second place in the number of individuals traded).
However, crowding and excessive handling, along with deteriorated water used to maintain these animals makes them vulnerable to attacks by diverse diseases, particularly those caused by bacteria, which lead to premature deaths.
Links of diseases
The project began from the premise of ignorance of the precise causes and factors leading to the deaths of these freshwater species in Colombia. "No systematic work had been carried out according to regions and species that would give us that information. We suspected that they were being improperly handled throughout the chain of extraction, with grave repercussions on their health and on the environment" according to professor Carlos Iregui, leader of the Veterinary Pathobiology Group at the Universidad Nacional and a researcher into infectious diseases among fish and mammals.
Colombia has not specialized in the raising of these species but rather on their extraction, says Giovanni Penagos, a veterinarian from the UN. "This activity is neither viable nor sustainable over the long term, so our research seeks to create health bases and to determine the factors that influence the pathologies that affect them, so as to contribute towards their sustainable production".
The study followed up on each link in the fish commercialization chain, taking water samples to measure quality parameters, and fish tissue samples to determine the disease and cause of death of the individuals, according to veterinarian Paola Barato.
Demands of the chain
The process consists first of all of the fishermen. According to Barato, "it is not a mass labor, but rather there is an art of fishing for each species, and in many zones those who capture them are indigenous people".
Subsequently, the fishermen store the fish in cement basins, aquariums and earthenware tanks. They are in constant contact with the exporter and those responsible for sending the final product to the purchasers, who are almost always international ones.
The most sought after and costly decorative species in Colombia are the ‘arawana azul’, which is found only in the Department of Vichada, the manta rays that mostly come from the rivers of Orinoquia, and other species such as the ‘cucha real rayada’ and ‘arawana plateada’.
In order to regulate fishing in the country, the Colombian Agricultural and Livestock Raising Institute (Instituto Colombiano Agropecuario – ICA) has established annual fishing and export quotas for each species as well as prohibited periods in each region to avoid overexploitation.
Diseases of freshwater species
The UN researchers, led by microbiologist Judith Figueroa, examined around 4,000 decorative fish belonging to more than 100 species from the departments of Vichada, Guainía, Putumayo, Amazonas and Meta and from export warehouses in Bogotá.
After clinical, histopathological, stereological and molecular biological analysis of the individuals, it was found that the main cause of mortality and disease are bacterial infections, mainly those caused by Aeromonas hydrophila. These bacteria affect a large number of highly sought after fish such as the ‘cuchas’, ‘cardenales’, ‘escalares’, ‘sapuaras’ and ‘estrigatas’, among others. "The infections are associated with overcrowding, excessive handling of the fish and sudden alterations of water quality, mainly levels of oxygen, temperature and ammonium", said the veterinarian from the UN.
Diseases were also identified that caused serious problems in particular species, such as branchial parasitisms stemming from Piscinoodinium in ‘cuchillos’, gastrointestinal coccidiosis in ‘estrigatas’ and skin infections compatible with flavobacteriosis in ‘monedas’. In this regard, Penagos affirms that "it involves alterations that tend to strike particular families or species and need to be handled differently from the moment of capture".
In a number of species, infections were also found due to mycobacteria (tuberculosis). In addition to the difficulty in controlling those diseases, the bacteria can cause skin infections among humans, which is why special handling is required at the storage sites.
The study creates a basis for improving the quality of health of aquarium fish exported from Colombia, and makes it possible to affirm that the country currently does not have diseases that lead to restrictions or health vetoes from the World Trade Organization. A book with the results will be published, under the title Mapa epidemiológico de las enfermedades de los peces ornamentales en Colombia (Epidemiological Map of Diseases of Decorative Fish in Colombia) along with two booklets on public health handling.
The research was financed by the Ministry of Agriculture and Rural Development, in partnership with the Universidad Nacional de Colombia, the Universidad de los Llanos, JCF Caribefish and Coopesca.