Chilean Salmon Farming on the Horizon of Sustainability: Review of the Development of a Highly Intensive Production, the ISA Crisis and Implemented Actions to Reconstruct a More Sustainable Aquaculture Industry - Aquaculture and the Environment: A Shared Destiny - page 233

Year 2005 2006 2007 2008 2009 2010

Active principle

Emamectin benzoate (kg) 240 443 595 285 65 47

Diflubenzuron (kg) 0 0 0 162 3878 3639

Deltamethrin (1%)* 0 0 516 10524 3168 3431

Cypermethrin (5%)* - - - - - 593

*values are given in litres

Table 6. Antiparasitic drugs used through feed or bath treatments.

may have contributed to the risk of disease transfer in Chile. In spring of 2007, barely four
months after the detection of ISAv in two sites around Chiloé Island, the number of
infected sites had tripled (Carvajal, 2009). Nevertheless, the industry was optimistic and
considering that as an isolated event limited to one farming company, and there were
little sense that this could be a catastrophic event. Although the industry argued that the
media was blowing the situation out of proportion, a few months later ISA had reached
all salmon producing regions in Chile, affecting almost every salmon farming company.
At this point, the need of a consorted action between the authorities and the industry was
evident. The disease began to spread in late December 2007. Outbreaks were reported in
Aysén region and ISAv positive fish in different sea sites and broodstock were reported
late in 2008. Between July 2007 and July 2008, 74 sea sites, presented positive results to
virus detection, out of which 44 were classified as focal outbreaks. Among the positive
farms, 89% were located in Los Lagos region and the remaining 11% in Aysén region.
Furthermore, the impacts of this disease account for the elimination of >11,000 tons of fish
distributed in 250 sites which belonged to 13 different companies. The ISA outbreak
reached its peak in 2008 affecting 93 sites (Silva, 2010b). However, there was a progressive
decrease in outbreak reporting since 2008, with 3 outbreaks in late 2009 and 4 outbreaks in
2010. This decline is explained by the decrease in active sites, where the industry capacity
of 550 authorized sites was operating in only its 20%. It can also be noted that the area
with most outbreaks was Central and Southern Chiloé where barely 180 sites were
operating during 2009 (Silva, 2010b). As a consequence of ISA, Chile stopped earning
more than USD 883 million in 2008 (Silva, 2010b). In 2009, the industry export volumes
fell by 16% and earnings experienced a decrease of 12% compared with the previous year
(Silva, 2010c). When ISA outbreaks started, the smolts transferred in to sea sites decreased
in about 600 thousand a month. In 2006 about 12 million smolts were transferred per
month. The smolt release in 2009 was reported to be less than the tenth of what was in
2007 (Asche et al., 2010), and a fall of 83% in January 2009 when compared with the same
period in 2008. In mid-2009 the situation began to improve, and in mid-2011, every 30
days, four million smolts were transferred and the figure is increasing. This is due to
changes in the production model, which has reduced mortality. During January 2010, the
number of fish in farms was 61% of what was in 2008. During 2010, the exports reached
352,637 tons a 23% less than the previous year, showing a variation in earnings of only -
2% (TechnoPress, 2010). As of July 2011, about 20 sites have been reported as ISAv HPR0
positive, a low-pathogenic variant, only one site has been confirmed to remain in outbreak
due to a pathogenic strain (HPR2). This number of infected sites well correlates with
increasing aquaculture activities after the crisis.