Abstract

Successful health management of farmed fish is essential for sustainable mariculture. The level of potential control of parasites is related to the type of aquaculture system. Cage culture offers little control over parasitic infections. Additionally, interactions between farmed fish and wild fish are unavoidable in cage culture. Parasites can cause significant losses and contribute to production costs through the costs of treatment and loss in growth of the fish. Sea lice are one of the most significant health problems in mariculture worldwide. All major producers of Atlantic salmon are significantly affected by different species of sealice. While there are commercial treatments available, development of resistance can reduce usefulness of some of those products. Sealice can also affect farming of other mariculture species, such as tuna. Amoebic gill disease (AGD) is a condition affecting some species of farm-reared marine fish caused by Neoparamoeba perurans. AGD was initially reported only in Australia and USA but by now it has a significant impact on salmon production in Australia, Scotland, Norway and Ireland. Main treatments used commercially include bath treatment with fresh water or with hydrogen peroxide. Tuna mariculture in Japan and Australia is affected by blood flukes from genus Cardicola. Currently praziquantel is used as a treatment but there is a growing concern that the blood flukes may develop resistance. Improved knowledge of the parasites and host-parasite-environment interactions has resulted in development of management strategies which reduce impact of parasitic diseases in mariculture.