Caligus Rogercresseyi – Gross Pathology

Atlantic salmon with adult females (C. rogercresseyi). Note the lesions on the skin surface. Note also the paired trailing egg sacs.

Caligus rogercresseyi is a predominant parasitic problem in the salmonid industry in Chile. It mainly affects Atlantic salmon and Rainbow trout. Coho salmon is not considered susceptible due to a well-developed inflammatory response. The life cycle of C. rogercresseyi is composed of eight stages of development, two nauplius stages I and II, an infested copepodite stage, four chalimus stages and an adult stage (young adult and mature adult). The amount of time it takes for a louse to develop depends greatly on the temperature. Under...