Aggregata infection in the common octopus, Octopus vulgaris (Linnaeus, 1758), Cephalopoda: Octopodidae, reared in a flow-through system

Abstract

Along with the introduction of the common octopus (Octopus vulgaris) to rearing systems in the Mediterranean by fattening or experimental paralarval production, emergence of diseases has become a concern. The most devastating infection of reared octopus stock is the coccidian parasite Aggregata sp. (Apicomplexa: Aggregatidae) that causes weight loss, excitation and behavioral changes, and miliar subcutaneous parasitic cysts. During eight months of experimental fattening of common octopus in the aquaculture facilities of the Institute of Oceanography and Fisheries (Split, Croatia), 7% mortality was attributed to infection by Aggregata sp. Although the detailed life cycle of the genus Aggregata is not yet completely elucidated, it is known that this heteroxenous coccidian uses crustaceans for merogony, which comprise 30% of the cephalopod’s diet. For the moment, only adequate zooprophylactic measures can prevent the emergence of the infection in the rearing system. Preventing introduction of adult specimens into the rearing system is a critical zooprophylactic measure, along with stocking only juvenile cephalopods that are uninfected by the coccidian through the food web in the natural environment and are, thus, unable to introduce the infection into the rearing system. The second measure involves avoiding crustaceans in the rearing diet.