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 232

Year 2005 2006 2007 2008 2009 2010
Active principle
Oxolinic acid (kg) 50,713 39,035 74,582 25,325 2,900 1,192
Amoxicillin (kg) 97 253 1,732 349 473 863
Erythromycin (kg) 1,994 1,972 2,139 7,981 1,542 2,586
Florfenicol (kg) 33,258 102,838 143,009 184,715 113,137 74,431
Flumequine (kg) 96,751 95,575 74,773 32,293 3,233 1,588
Oxitetracycline (kg) 56,354 104,135 89,309 74,931 63,172 62,506
Sulfa+trimethoprin (kg) 0 1 91 22 11 -
Total (kg) 239,167 343,808 385,635 325,617 184,469 143,165
Table 5. Amount of antibiotics used by the Chilean salmon industry, by active principle and
year.
the course of the years has led to the emergence of resistant organisms (San Martin et al.,
2010). Due to the low number of antibiotics approved, it is suggested to register new drugs
in the country, or to allow the extra-label use of antibiotics, because the latter would allow
veterinarians to use other drugs that are not registered for salmon but within the legal
framework. However, this process is not authorized (San Martin et al., 2010).
Several chemotherapeutants have been used to control caligidosis in Chile, e.g. metriphonate
(Neguvon TM ) was the first product used to control Caligus teres between 1981 and 1985,
replaced by another organophosphate, diclorvos (Nuvan TM ) between 1985 and 2000, both
used as bath treatment. Ivermectin use in feeds was introduced in Chile at the end of the
1980s, but between 2000 and 2007 the only veterinary product authorized for this use in Chile
was the avermectin (emamectin benzoate EMB), without alternative treatments available.
When EMB (Slice TM ) was introduced into the Chilean market in 1999, one standard treatment
with the product (50 µg of active ingredient per kilogram biomass daily for 7 day) controlled
the sea lice infestations on the salmon for at least five weeks in the summer and even longer
in the winter (Bravo, 2003). Since early 2005, a notable loss of efficacy was observed in several
fish farms, resistance development was the main cause (Bravo et al., 2008). Within the
management of this parasitic disease, a strategy of coordinated treatments was established by
the authority, which aimed to reduce the infestation levels over subzones or groups of
concessions. Today, there are 10 commercial products for caligidosis treatment authorized by
SAG. The current compounds for treatments are deltametrine 1%, diflubenzuron 80% and
emamectin benzoate 0.2% (Table 6). The last antiparasitic drug authorized was cipermetrin
5% (Betamax) (SAG register No. 2085, 2010).
4. Sanitary crisis of the Chilean salmon industry
The ISAv crisis may not be exclusively related to the rapid spread of a highly virulent
pathogen. Prior to the ISAv outbreak, the industry struggled with serious caligidosis and
piscirickettsiosis outbreaks, especially in Los Lagos region (X). In addition, several factors
affecting the quality of the smolt has not been fully tackled such as excessive handling,
grading, varying FW quality, high density, and water quality and welfare in long distances
on land and sea transport. Perhaps one of the most threatening practices in Chilean salmon
farming that relate to spreading of diseases was the inadequate disinfection management of
wastes from processing facilities. Additionally, boat travel between the farming facilities