Chile's salmon farmers defend highest antimicrobial use since 2017

Chile’s salmon farmers increased their use of antimicrobials last year to levels not seen since 2017, according to the latest report on the matter from the Chile’s National Fisheries and Aquaculture Service (Sernapesca).

Sernapesca reported Chile's salmon farmers used 463.4 metric tons (MT) of antimicrobials on 985,958 MT of harvested biomass in 2021, leading to an antibiotic consumption index (ACI, or amount of active ingredient used divided by the harvest of salmonids times 100) of 0.047 percent. In comparison, the industry's ACI was 0.035 percent for 2020 and 0.046 percent in 2017. The highest ACI recorded in the report was 0.064 percent in 2007. Until last year, antibiotic use had been steadily falling since 2015, when ACI reached 0.063 percent.

“The SARS-CoV-2 pandemic generated logistical complications in companies that resulted in delays in harvesting and processing times, which led to the extension of production cycles, prolonging the exposure of greater biomass to pathogens,” Sernapesca Deputy Director of Aquaculture Marcela Lara said. “In addition, harmful algal bloom events occurred in the regions of Los Lagos and Aysén during 2021, which adds a stressor that affects the immune response of fish, producing an increase in the incidence of treatments against piscirickettsiosis.”

Chile's salmon trade groups were quick to react to Sernapesca’s latest report. The Salmon Council – which represents AquaChile, Australis, Cermaq, Mowi and Salmones Aysén, companies that make up more than 50 percent of national production – said that while antibiotics use increased 34 percent in 2021 compared to the previous year, the trend is still decreasing when considered over a longer period of time. Levels in 2021 decreased 25 percent when compared to 2015, for example.

Unlike salmon farming in the Northern Hemisphere, where fish diseases are mostly viral and are not treated with antibiotics, in Chile, there are oceanographic and biological conditions that favor septicemia rickettsial salmonídea (SRS), the council noted. The bacteria is controlled with different preventive measures, with the use of antibiotics being the last recourse. Antibiotics are not used for preventive purposes, but only in response to the presence of disease and under veterinary prescription with medicine approved by Chile’s Agricultural and Livestock Service (SAG) and reported to Sernapesca, the council said. Further, before being harvested, antibiotics use is suspended for a certain period of time to guarantee that it is eliminated from salmon tissues. Sample specimens are examined in laboratories to ensure food safety, it said.

“Ensuring animal health is part of the production process of all animal-origin proteins, and salmon farming is no exception. Salmon are living beings and, as such, their well-being must be safeguarded and done in an appropriate way to produce healthy proteins,” Salmon Council Executive Director Joanna Davidovich said. “Strategies to optimize antibiotics use must be worked on with a long-term perspective and Chilean salmon farming will continue to work actively to address this challenge.”

SalmonChile, Chile’s salmon industry association, which said it was addressing “public opinion and the more than 71,000 employees” in the salmon industry, responded in a statement that the Sernapesca report is in line with its policy of transparency, which has been reflected for the past seven years in its publication of an annual sustainability report that includes indicators in matters such as antibiotics use, fish mortality and diseases, the payment of aquaculture licenses, and community actions.

“The commitment of SalmonChile and its production companies to improve standards and operations on a daily basis, as well as to reduce the use of antibiotics, is undeniable. For years, the use of antibiotics has decreased drastically and therefore we can affirm that the increase in the use of these medicines during 2021, compared to 2020, is an exception to the work that we have been doing and that is mainly due to the effects of the pandemic and other environmental effects,” SalmonChile said.

SalmonChile has been working with the Monterey Bay Aquarium since 2018 to halve antibiotics use by 2025, “a decrease that in the last five years had been effective and that has been reinforced thanks to the joint work with this prestigious NGO.”

The Salmon Council also highlighted its work with the Monterrey Bay Aquarium’s Seafood Watch for Aquaculture and its Chilean Salmon Antibiotic Reduction Program as having a beneficial impact on salmon health and the environment. Salmon Council member-companies have worked to increase the number of their centers certified by the Aquaculture Stewardship Council (ASC), which allows for the use of drugs within certain limits “because it [ASC] understands that animal protein production requires looking after their well-being in responding to diseases.”

The Salmon Council said Chilean salmon is considered one of the healthiest proteins globally and that its consumption is safe, as it is backed by national regulations. Moreover, the multiple international markets to which Chilean salmon is exported impose high product standards, it said.

For its part, Sernapesca said it is expanding the monitoring of the susceptibility of pathogens to antimicrobials in grow-out centers that perform repeated treatments; implementing a new version of the online veterinary medical prescription system (ONLINE PMV) for better control over antimicrobials use; and reinforcing the PROA-SALMON certification program, which recognizes cultivation centers that voluntarily subscribe to the program and integrate health policies for the reduction and optimization of antimicrobial use. The latter program was launched in March 2020, and to date has received 263 applications for registration – of which 58 farming centers’ production cycles from 11 salmon-producing companies have been certified. It said 47 centers participating in the  program did not use antimicrobials at all in their most-recent farming cycles.

“We call on the industry to go beyond the norm and proactively strengthen its preventive strategy for the control of infectious diseases, and thus strengthen the system of early detection and timely control to return to the sustained reduction in the use of antimicrobials registered since 2015,” Sernapesca’s Lara said.

The two industry groups said Chile’s salmon industry is ready to adopt the enhanced measures called for by Sernapesca.

“We value Sernapescsa’s supervisory role and share with them the importance of establishing public-private working groups to continue developing aquaculture in the south of Chile. We are available for that constructive dialogue with a country vision,” SalmonChile said.

Other findings in the Sernapesca report include:

• The highest users of antimicrobials in the report (with an index measured by grams of antimicrobials divided by MT of biomass produced) included Empresas Yadrán (with an index of 748), Productos del Mar Ventisqueros (728), Salmones Camanchaca (696), Salmones Austral (572), and Empresas AquaChile (569).
• The lowest users of antimicrobials included Caleta Bay (with an index of 22.7), Salmones Aysen (56.7), Australis Mar (174), Blumar (186), and Cooke Aquaculture (186).
• The Magallanes Region actually saw a decrease in the use of antimicrobials, with 14.70 MT consumed in 2020 versus 8.44 MT in 2021, down 42.6 percent.
• There was also a 40.8 percent decrease in freshwater antimicrobials use on the national level, moving from 9.97 MT in 2020 to 5.9 MT in 2021.
• In 2021, 54.3 percent of the antimicrobials used in the at-sea grow-out stage corresponded to the Aysén region, 43.6 percent to the Los Lagos region, and 1.87 percent to the Magallanes region.
• By species, 92.8 percent of antimicrobials used last year were for the cultivation of Atlantic salmon, 5.11 percent in coho salmon, and 2.05 percent in trout.  

Photo courtesy of Sernapesca