Prevalence, infestation, and morphological characterization of the fish parasitic isopod Alitropus typus

The infestation of crustacean parasites affects the freshwater and marine fishes, causing retarded growth rate, reduced production, low reproduction, and mass mortality. Fish parasites from the isopod family Aegidae, in recent years, have received increased global attention due to their serious socio-economic, ecological, and welfare consequences in finfish aquaculture. This is particularly true for the buccal-inhabiting genus Alitropus typus, which has emerged as a major parasitic threat to freshwater and brackishwater fish populations across tropical and subtropical regions, adversely affecting the health of both farmed and wild-caught fish. As research on this group increases, so does our understanding of their prevalence, infestation, and morphological characterization. The present review focuses on the infestation, intensity, prevalence, and diversity of A. typus in different fish communities. The biochemical composition of crustaceans and various control strategies, including the use of chemicals, vaccination, and biological treatments, are briefly described and explained. The risk of parasite transmission from the aquaculture enterprises to wild fish populations underscores the urgent need for the initiation of control programmes to safeguard the original endemic fish stocks. The review aims to highlight the advantages of using bacteria as an alternative treatment to eradicate parasites in aquaculture and to show the possible negative environmental impacts of chemical treatments used in fish farming systems. Finally, we also highlight the potential of the bacterial consortium to control parasites in fish farming as it assures health health-promising effect to the fish community due to parasiticidal activity without any side effects.