Santiago, May 19, 2022. (Ecoceanos News)— The mega-industry producing and exporting salmonids that operates in Chile increased the use of antibiotics in its farms by 33% during 2021, according to reports from the state-run National Fisheries Service. and Aquaculture (Sernapesca).
The «Report on the use of Antimicrobials by National Salmon Farming 2021» established that in 2021, industrial salmon monocultures operating in Chilean waters used 463.4 tons of antimicrobial active ingredient (463,400 kg.), a sharp increase compared to 379 .6 tons used in 2020.
This information set off alarms among researchers, public health specialists, and Chilean international and socio-environmental consumer organizations, because veterinary medical treatments would not be effective in terms of time, quantity, and type of antimicrobial supplied. Added to the foregoing is the non-delivery of all the information required by the salmon companies.
Chilean salmon farming in the opposite direction to the WHO call
While the World Health Organization (WHO), dependent on the United Nations, has called on the Member States to fulfill the commitments derived from the global strategy «One Health» to combat bacterial resistance, reducing the use of antimicrobials in animal production, Chile-based salmon farming continues to increase its use for intensive salmon production, with the potential impact of increased bacterial resistance in southern aquatic and terrestrial ecosystems.
Some hypotheses about the increased use of antimicrobials in the salmonid export industry
Sernapesca detected for 2021 an increase in the use of antimicrobials compared to the previous year. «In 2021 we registered an increase in the use of antimicrobials in the fattening stage in the regions of Aysén and Los Lagos, mainly for the treatment of Piscirickettsiosis (SRS) in Atlantic salmon,» said the regulatory body.
After analyzing the Sernapesca report, Dr. Rubén Avendaño-Herrera, principal investigator of the Interdisciplinary Center for Aquaculture Research in Chile (INCAR), stated that “although the 2021 Antimicrobial Use Report provides transparent quantitative information on the amounts used, the antibiotics used and the amount used by the companies, it is unknown whether the therapy was effective or not in ending an infectious condition” (1)
“If there is a therapeutic failure, it could be because the antimicrobial did not reach the place where the pathogen was, or less “quantity” arrived, so the bacteria was exposed to an under-dosage causing, in an undesirable way, a lower susceptibility of the pathogen to the same antimicrobial”, pointed out the INCAR researcher.
The Deputy Director of Aquaculture of SERNAPESCA, Marcela Lara, explained that «the SARS-CoV-2 pandemic generated logistical complications in companies that involved delays in harvesting and processing times, which led to the extension of production cycles prolonging the exposure from higher biomasses to pathogens”.
In addition to this, the state official added, «the occurrence of harmful algal bloom events found in the Los Lagos and Aysen regions during 2021, which adds a stress factor that affects the immune response of fish, producing an increase in the incidence of treatments against Piscirickettsiosis».
The Sernapesca report indicates that during 2021, 54.34% of the antimicrobials used in the fattening stage in the sea correspond to the Aysen region, 43.66% to the Los Lagos region and 1.87% to the Magellan region. Meanwhile, in the analysis by species, 92.83% of the antimicrobials are used in the farming of Atlantic salmon (Salmo salar), 5.11% in coho salmon and 2.05% in rainbow trout.
Types of pathogens and antimicrobials used in the farming phases of industrial chemical salmon
Of the 242.39 tons of active ingredient used during the first semester of the current year, 98.96% was administered in the sea phase and 1.14% in the fresh water phase. In this last phase, 69.17% of the antibiotics used corresponded to oxytetracycline, 28.28% to florfenicol, 2.09% to erythromycin, and 0.47% to tilmicosin. The use of oxytetracycline decreased from 82.34% in 2020 to 69.17% in 2021, while florfenicol increased from 13.03% to 28.8%.
The Sernapesca report details the percentage distribution of the number of antimicrobials administered per diagnosis. In both stages of the production cycle, there was an increase in the percentage of drugs used to treat flavobacteriosis (49.43% to 70.34%), and a reduction in the treatment of renibacteriosis (49.37% to 29.35%).
In the seawater phase, piscirickettiosis remained the main industrial disease for which antimicrobials are used (93.53%). Tenacibaculosis ranked second, after in 2020 it ranked third, after BKD. In the first half of 2021, a small percentage of antibiotics appear to treat flavobacteriosis in the sea (0.09%).
Ecoceanos Centre: Calls international consumers to be alert about the safety of industrial chemical salmon and its impacts on the Patagonian Sea
Faced with the increased use of antibiotics in the salmon industry that operates in Chile, Ecoceanos Centre called on Chilean and North American consumers of farmed salmon «to be alert and demand transparency in relation to food safety of farmed salmon production and its health-environmental impacts on the ecosystems and marine biodiversity of Chilean Patagonia”.
For her part, the executive director of Oceana, the veterinary doctor Liesbeth Van der Meer, stated that “in recent years we have witnessed a decrease in the use of antimicrobials in salmon farms. However, the industry is once again significantly increasing the use of these drugs (…) These figures correspond to the total for the industry, since to date there is no public access to disaggregated data, and we only have information on those companies that they agreed to deliver them, which does not allow us to evaluate the environmental behavior of each company».