Fish health and parasitic invasions in the Azov sea: Current trends and challenges

Abstract

This study investigates the parasite fauna and fish diseases in the Azov Sea Basin based on data published between 1996 and 2023. The research identifies 97 species of parasites across various fish species, highlighting the impact of environmental changes such as increased salinity and pollution on fish health. Key findings include the identification of pathogenic species affecting both natural water bodies and aquaculture. Fish serve as hosts for numerous parasites, including microsporidia (Loma mugili, Myxobolus sandrae, M. parvus), ciliates (Ichthyophthirius multifiliis), monogeneans (Dactylogyrus extensus, D. vastator, Diplozoon paradoxum, Gyrodactylus sprostonae, Ancyrocephalus paradoxus), cestodes (Caryophyllaeus laticeps, Khawia sinensis, Gryporhynchus cheilancristrotus, Ligula intestinalis, L. interrupta), and trematodes (Timoniella imbutiforme, Ascocotyle longa, Diplostomum spathaceum, Tylodelphys clavata). Additionally. Mollusks (Unionidae gen. sp.) and crustaceans (Achtheres percarum) are also of concern. Metacercariae of trematodes (Paracaenogonimus ovatus, Cryptocotyle concavum, C. lingua, Apophalus donicus) and larvae of nematodes (Hysterothylacium aduncum, Eustrongylides excisus) are potentially dangerous to the health of animals and humans. Monitoring the epizootic situation in the water bodies of the Azov Sea Basin, especially in the context of ongoing salinization, is crucial for fish health protection. Developing criteria for assessing parasitic pressure based on fish infestation and forecasting changes in the epizootic situation under changing environmental conditions is essential.