diferent families of shrimp show va

diferent families of shrimp show variable survival with aphns exposure. result will soon be know if this is heritable or not. in order to increase selection pressure; techniques have been worked out to repeatedly directly expose high levels of the bacteria and selec those individuals that survived to 30 grams. procedures are now in place to clean these exposed shimp. Exprerience has shown that broodstock size shimp are very refractory to the aphns bacteria (very hard to infect)