Common Cyclops

The common cyclops (Cyclops strenuus) is a small crustacean belonging to the order Cyclopoida. While generally considered part of the aquatic food web, it is classified as a pest in intensive aquaculture and hatchery systems, where its population density can severely impact the survival rate of young fish stocks.

The damage caused by Cyclops strenuus is primarily mechanical and biological. In hatcheries, adult copepods may swarm and attack fish larvae, attaching themselves to the skin or gills of the fish. This behavior causes stress, tissue damage, and increases the susceptibility of the fry to secondary bacterial and fungal infections.

Biologically, these organisms are highly resilient. The life cycle begins with eggs carried by the female in paired sacs, progressing through several naupliar and copepodid larval stages. They are extremely opportunistic feeders, capable of thriving in various water conditions, which makes their eradication in controlled environments difficult.

A significant aspect of their harmfulness is their role as intermediate hosts for various fish parasites, including tapeworms (Diphyllobothriidea). When fish consume infected cyclops, they become hosts for these parasites, which can lead to widespread disease outbreaks and significant economic losses in aquaculture operations.

Management and control strategies involve strict water filtration to prevent entry, as copepods are sensitive to fine mesh sizes. Regular cleaning of ponds and closed-loop systems is essential to break their reproductive cycle. In cases of high infestation, chemical water treatments or UV sterilization of inflow water are recommended to maintain a healthy production environment.