Biosecurity measures are any practices, procedures or policies in a farm in order to reduce the risk that pathogens will be introduced in the facilities, that the pathogens will be spread out around the facilities or reduce the stressful conditions of the fish that will enhance the susceptibiltiy of the fish for these pathogens once they are already introduced. What do we do in IRTA? One of the first measures to carry out in our biosecurity systems is to control the access of any person in the facilities. It is advisable to have a record of the visit, the name, the date and the purpose of the visit. Once in the facility, this person has to chanhe his clothes, wear lab coat and boots and pass the security entrance that is ... full with water and desinfectants. Another measure for biosecurity is to have all the systems separated, that means different zones for each work. For example, there is a place for the larval rearing, another place for artemia production, another place for Rotifer production and another place for the nursery. Once the fish enter the facility, they have to be kept in the best conditions for the rearing, so we have to keep control of the water quality, measuring everyday the oxygen, the temperature, salinity, amonia or nitrate production and keep the tanks clean, taking out all the feed that has not been consumed and also take out all the dead fish we can find. One of the biosecurity measures that we recommend is to have a record of all the fish that enter the facilities and all the treatments that we do, for example, changes of the fish from one place to the other, number of the dead fish during the time they are in the facilities or the chemical treatments that we use to prevent the diseases.