Progress of the studies on parasites in Cephalopods.

Cephalopods are widely distributed in the world's oceans and are among the most important species in the marine ecosystem due to their short life cycle, fast growth rate and extremely rich biomass. Like other marine organisms, cephalopods are at risk of being infected by parasites, often acting as either intermediate or final hosts for different species of parasites. Due to the unique life cycle of parasites, their life cycle can run through the entire or partial life cycle of the host, greatly affecting the growth and survival of cephalopods. Currently, research on parasites in cephalopods mainly focuses on species composition, life history, infection status, and other aspects. This article summarizes the current research status of parasitic infections in cephalopod marine animals. The results show that the main parasites infecting cephalopods are Dicyemida, Cestoda and Nematoda. Dicyemida parasitize cephalopods characteristically, with maturation and reproduction taking place exclusively in the kidneys of cephalopods. Available statistics show that there are 149 species of Dicyemida infecting cephalopods, mainly found within the Sea of Japan, with fewer species found at lower latitudes. Cephalopods, as intermediate hosts, are also susceptible to infection by Cestoda larvae and have a high infection rate. Cestoda mainly parasitize the digestive tract of cephalopods. Due to the large size, stretching, and mobility of Cestoda larvae, they are prone to cause mechanical damage to the host. Nematodes are another common parasites infecting cephalopods, and are primarily ingested as third-stage larvae of Nematodes, which mostly parasitize the stomach and cecum. Nematodes are among the most abundant and common species of cephalopod parasitic infections, and can have significant pathological effects on the host. Other types of parasites can also affect the physiological characteristics of cephalopods to a certain extent. Research on parasites in cephalopods is still in its early stages. Therefore, future research should focus on accelerating the establishment of an open database of parasites in cephalopods, expanding and sharing information on parasite species. It is also important to deeply explore the life processes of parasitic species in cephalopods to further understand their impact on host growth. Additionally, using parasites in cephalopods to divide population composition can provide new ideas for the sustainable development and utilization of cephalopod fisheries. [ABSTRACT FROM AUTHOR]