Workshop to promote the programs “Evaluation and monitoring of the health status of wild fish in freshwater and seawater, 2023-2024” and “Determination and surveillance of Caligus rogercresseyi resistance to antiparasitics applied in national salmon farming, Stage VII, 2023-2024”.
October 4th, 2024
This Thursday, September 26, the Workshop to Promote the programs “Evaluation and monitoring of the health status of wild fish in freshwater and seawater, 2023-2024” and “Determination and surveillance of Caligus rogercresseyi resistance to antiparasitics applied in national salmon farming, Stage VII, 2023-2024” was held. The activity was organized by the Department of Hydrobiological Health, of the Aquaculture Research Division of the Fisheries Development Institute (IFOP).
The workshop began with welcoming remarks from Gastón Vidal, head of the Aquaculture Research Division, who highlighted the importance of the workshop in the national context.
On behalf of the Undersecretariat of Fisheries and Aquaculture, Daisy San Pedro presented the research program on aquaculture management, highlighting its relevance in the regulation and conservation of hydrobiological resources. She explained the process of developing the program, which includes receiving proposals, approving budgets and the annual validation of permanent projects. Health and surveillance programs were also addressed, highlighting the advances in monitoring the health of wild fish and the susceptibility of Caligus rogercresseyi to different drugs.
“Evaluation and monitoring of the health status of wild fish in freshwater and seawater, 2023-2024”,
Juan Carlos Quintanilla, researcher at the IFOP Hydrobiological Health Department and who leads the program, presented the results, both historical and for the last stage (2023-2024), of the monitoring carried out on wild fish and free-living salmonids, in the detection of the main pathogens causing High Risk Diseases (HRD).
Additionally, he indicated that this program has been underway for more than a decade, carrying out surveillance on 14 pathogens causing HRD in a total of 21 areas distributed between the regions of La Araucanía to Magallanes and the Chilean Antarctic. He highlighted in his presentation that, of the total number of pathogens under monitoring, only the bacterial agents Piscirickettsia salmonis, Flavobacterium psychrophilum, Renibacterium salmoninarum, and the viral agents Piscine orthoreovirus (PRV) and Infectious Pancreatic Necrosis Virus (IPNV) have been detected.
To conclude his presentation, Juan Carlos Quintanilla points out that the increased detection of pathogens in wild fish raises the epidemiological importance of these, in their potential role as reservoirs, maintainers and/or transmitters of pathogens, which cause EAR affecting farmed salmonid species.” Finally, he added that “further research is needed to elucidate the dynamics and mobility patterns of wild fish populations.”
“Determination and monitoring of Caligus rogercresseyi resistance to antiparasitics applied in national salmon farming, stage VII, 2023-2024”.
Dr. Jaiber Solano, IFOP researcher, presented the historical trends of in vitro susceptibility of Caligus rogercresseyi to three drugs mainly: azamethiphos, deltamethrin and cypermethrin. In relation to this, Dr. Solano highlights the loss of susceptibility observed for azamethiphos and deltamethrin, unlike cypermethrin, where a stabilization and even greater susceptibility of sea lice to this drug has been observed. He highlights that, unlike the first two drugs mentioned, the use of cypermethrin in national salmon farming has practically disappeared since 2017.
Additionally, within the results of this program, a marked increase in the effective concentration 50 (EC50) for Hydrogen Peroxide was highlighted, from 2022 to date. Highlighting then the loss of in vitro efficacy of this antiparasitic compound.
Finally, within the short-term projections of the program, Jaiber highlights the beginning of experimental caligus infestation trials, for the validation of protocols for the surveillance of other antiparasitic compounds that are widely used today in the industry and that, therefore, are of great interest for surveillance.
Dr. Diego Valenzuela: The Caligus rogercresseyi genome as an input for the control of caligidosis
As a complementary activity to the dissemination of the results of two of the IFOP surveillance programs, Dr. Diego Valenzuela-Miranda, researcher at the Interdisciplinary Center for Aquaculture Research (INCAR), addressed the study of the Caligus genome and its impact on the aquaculture industry, highlighting the need to develop new non-pharmacological control mechanisms due to the observed drug resistance of the parasite. The first version of the Caligus rogercresseyi genome was presented, indicating that it consists of 21 chromosomes, 505 mega bases and 24,000 coding genes, highlighting that obtaining this information was “quite important as a center and gives us guidelines for the development of new Caligus control strategies, but also, for example, new strategies for monitoring drug resistance,” adding that this information contributes significantly to the development of new treatments against Caligus and particularly associated with the development of vaccines against caligiosis.
Dr. Valenzuela presented the results of the experimental efficacy of vaccines that have been developed at the INCAR center, as well as the projections of the center regarding the validation of molecular markers that help predict the susceptibility of caligus to antiparasitics, based on genomic duplications.
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