Latin American & Caribbean Aquaculture 2025

October 7 - 9, 2025

Puerto Varas, Chile

Add To Calendar 08/10/2025 11:40:0008/10/2025 12:00:00America/GogotaLatin American & Caribbean Aquaculture 2025INTERDISCIPLINARY CHALLENGES OF PARASITISM IN AQUACULTURE: FROM MOLECULAR RESEARCH TO ECONOMICS IN THE CASE OF SALMON-CALIGUSArrayánThe World Aquaculture Societyjohnc@was.orgfalseDD/MM/YYYYanrl65yqlzh3g1q0dme13067

INTERDISCIPLINARY CHALLENGES OF PARASITISM IN AQUACULTURE: FROM MOLECULAR RESEARCH TO ECONOMICS IN THE CASE OF SALMON-CALIGUS

Caligus rogercresseyi parasitizes salmon farming in Chile, causing losses estimated in 450 million dollars per year. The INCAR center has focused on the study of this parasite from  molecular, ecosystem, and economic analytical perspectives . The result is a cross-disciplinary insight that offers different avenues for reducing the negative effects of this parasite on salmon farming.

 Currently, caligidosis is mainly controlled through pharmacological treatments, that have become less effective due to ectoparasite’s resistance. W e have worked on the development of vaccines for the control of caligidosis using various alternatives, such as recombinant and antimicrobiota vaccines, which have been evaluated for both injectable and oral application. Experimental evaluations in Atlantic salmon show high efficiency in reducing the parasite load of injectable and oral vaccine prototypes, both recombinant and Caligus microbiota. Both types of vaccines have been shown to increase the immune response of fish after 30 days of immunization, with protection lasting up to 3 months in some cases, making these vaccine prototypes an excellent alternative for controlling  C. rogercresseyi . T he possibility of administering these vaccines through feed reduces fish handling compared to products applied through baths, positively impacting fish welfare.

Marine ecosystems of southern Chile are subject to growing levels of stress due to joint effects of increased farmed salmon biomass  and  oceanographic/atmospheric variability  that can  alter their dynamics by extended time periods . Major Caligus rogercresseyi outbreaks represents a response of these stressed ecosystems  that  was analyzed  using  abundance time series  of ovigerous female and total adults between 2012 and 2022 detected in farms from salmon neighborhood areas . Main periodic mode of oscillations were detected using wavelets, and major outbreaks were identified when thresholds of 13°C and 12kg/m3 where surpassed. Early warning indicators were successfully used to detect  in advance  major  sea lice outbreaks associated with atmospheric/climatic transitions points . The Hurst coefficient (H )  and the weighted permutation entropy  as complexity measures  detected a transition from a long-term persistence  state (H =0.65), towards a state where abundance fluctuates randomly (H =0.53)  and  is  characterized  by a decrease in predictability.

The impact of sanitary treatments to control Caligus rogercresseyi abundance on unit production costs of  Salmo salar farms in Chile was measured . Complete production cycles for a sample of farms between 2009 and 2015 were followed and  a simultaneous salmon biomass growth and Caligus abundance model was estimated with panel data models . The statistical analysis determines the effect of antiparasitic treatments, location of farms, environmental conditions and Caligus abundance on the salmon growth profile. Using outside information unit production costs, variable by treatment and farm characteristics, were estimated . The results suggest that unit production costs increased on average by $1.4 US/kg with Caligus and treatments. Treatment costs are compensated by higher harvesting levels, and unit production costs are invariant to the situation without treatment. All estimated effects differ depending on farm’s environmental and spatial conditions, suggesting that the design of cost-effective intervention calls for discriminatory regulation under heterogeneous conditions.