The Disease of the Scallop Mizuhopecten yessoensis (JAY, 1857) in the Mariculture Farms of Primorye Caused by Protozoa of the Genus Perkinsus Levine, 1978

Abstract

The results of a study of the cultivated yesso scallop Mizuhopecten yessoensis (Jay, 1857) in Primorsky Krai in 2014–2021 are presented. The death of molluscs in mariculture farms was noted, the symptoms of the “dermo” disease were studied: high mortality of scallops that have reached 2 years of age, observed during autumn displacement into new cages in September, the presence of protozoa of the genus Perkinsus Levine, 1978 in the tissues of organs, foci of damage of the adductor muscle, nonclosure of the shell valves, black discoloration, necrotizing of soft tissues. The minimum level of the parasitic load was established as 10–15 parasitic hypnospores per mollusc. However, considering the danger of a disease that causes mass death of molluscs for several years, the rapid spread of the pathogen, and significant economic losses, it is recommended to create a specialized laboratory in the region for diagnosing and constantly monitoring the state of mariculture farms.