Chile recorded only one ISA outstanding outbreak in 2023

Chile's National Fisheries and Aquaculture Service (Sernapesca) has published its Salmon Farming Health Report corresponding to the operations registered in 2023. In this report, perhaps the most outstanding feature compared to the news in other producer countries is that only one infectious salmon anemia (ISA) outstanding outbreak was recorded in 2023.

The report describes the productive and health situation of the Chilean salmonid industry, both in freshwater and at sea, as well as the sanitary condition concerning the diseases covered by the Specific Surveillance and Control Programs for Infectious Salmon Anemia (ISAv), Caligidosis and Piscirickettsiosis.

As usual, the data analyzed come from the mortality declarations of the sea and freshwater farming sites grouped by region, and their associated causes. In addition, this latest report also incorporated a new section on mortality by cycle, including the number of dead fish and the percentage of cumulative mortality, differentiated by species, region, and even company.

"As required by the regulations, in the framework of transparency, it is essential to make this report available to users and the public, so that they can learn about the productive and sanitary performance of the salmon industry. This report is generated from the information of the sanitary surveillance system implemented by Sernapesca," said Mónica Rojas, Deputy Director of Aquaculture of Sernapesca, emphasizing the importance of making public the information on the audits of the aquaculture industry.

"Chile continues to be a country free of high-risk diseases"

Regarding the health situation, as mentioned above, the most outstanding aspect was the cases of infectious salmon anemia. Regarding ISA, the prevalence of the 'other HPR' (highly polymorphic region) variant - pathogenic, which produces the clinical picture of infectious salmon anemia - was 0.3%, with only one outbreak in 2023.

This outbreak was recorded in a farming site in the Magallanes Region, the Punta Entrada site operated by Aquachile. It was categorized as such because it showed clinical signs associated with the disease. However, thanks to the measures taken following Sernapesca's surveillance and control program for this disease, the outbreak was contained and its spread to other farming sites was prevented.

In its release, Sernapesca stressed that this control is a demonstration of "the importance of the biosecurity measures implemented in the country, as well as early detection and timely control."

Regarding Caligidosis, during the first half of 2023, it showed an average weekly load below the 3.0 HO threshold in Los Lagos and Magallanes regions. In contrast, in the Aysén region, parasite loads were variable, exceeding the 3.0 HO threshold only in November.

Although the report refers to last year, it is worth noting here that, in August 2024, Chile exceptionally authorized the pharmacological treatment of Caligidosis outside the official bathing windows, when carried out in watertight vessels. This new treatment alternative favors preventing and controlling Caligidosis in salmon farms.

By species, in terms of infectious mortality (secondary classification) of Atlantic salmon, Piscirickettsiosis remains the leading cause with 44.7%, followed by Tenacibaculosis with 37.9%. Overall, compared to 2022, Piscirickettsiosis decreased by 8.1%, while Tenacibaculosis increased by 9%. For Coho salmon, the main infectious cause in 2023 was Bacterial Kidney Disease (BKD), while for rainbow trout, it was Infectious Pancreatic Necrosis (IPN).

Finally, the report highlights that thanks to its robust surveillance system complying with what is established by the World Organization for Animal Health (OIE), "Chile continues to be a country free of high-risk diseases included in List 1."

Atlantic salmon continues to account for the largest share of production

As mentioned above, in addition to addressing the health perspective, the report also provides data on the Chilean salmon industry from a productive perspective. Thus, the report indicates, for example, that the highest number of fish in stock was recorded in January and October, with 409.73 and 403.36 million fish, respectively.

It also highlights that the highest number of sites and fish farms active in the freshwater stage was recorded between October and December, reaching a total of 140 at the national level. During 2023, the Los Lagos region reported the most activity, with 70 operational sites, followed by La Araucanía with 38, Los Ríos with 24, and Biobío with 12 freshwater sites.

In the case of sea sites, during 2023 there were a total of 600 operating. Aysén was the region with the highest number, reaching an annual total of 303 sites, an 8% increase compared to 2022. It was followed by the Los Lagos region with an increase of 6%, which was reflected in an annual total of 234 sites; and then, the Magallanes region, which, with 63, decreased by 9% in the number of active sites in 2023.

As for farmed species, even though compared to 2022 the sites stocked with it decreased by 0.3%, Atlantic salmon continues to accumulate the largest share of production with 64% of the sites operating in 2023. This is followed by Coho salmon with 28% - an increase of 25% compared to last year -, and rainbow trout with 7%, after a 19% decrease in the number of sites dedicated to this species compared to 2022.

Finally, concerning the mortality reports for the year 2023, Sernapesca highlighted there was a decrease in the percentage of monthly mortality of 0.11% compared to 2022. By species and for the accumulated mortalities of the farming cycles closed in 2023, the average mortality for Atlantic salmon was 9.4%, for Coho salmon it was 6.8%, and for rainbow trout, it was 6.9%.