Ecology: Reproduction in dioecious A. Although mating occurs on the body of the host fish, females lay 1—9 strings of 5— eggs in 1—6 rows on hard substrate, which they cover in gelatinous excretions. After hatching, the rest of the life cycle excluding egg-laying , takes place on the body of the host fish in 30— days. Argulus japonicus lays eggs continuously, although in winter eggs may stay dormant until warmer temperatures conducive to hatching occur in spring. As this species develops it passes through around 6 different larval instar stages before metamorphosing into an adult. Argulus japonicus has been recorded in mesohaline conditions in Chesapeake Bay, although most records in other parts of the world are from freshwater environments.
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Email: ude. Argulus spp can be a major threat to fish health, because heavy infestations can cause significant morbidity and mortality. In addition, fish lice are known to be the vehicle for other fish diseases. During rounds at our facility, Argulus japonicus was collected from the caudal and anal fins of 3 goldfish Carassius auratus.
These goldfish were asymptomatic, and no additional cases were noted after manual removal of the lice. As soon as any Argulus organisms are identified, management and treatment are recommended because infections can escalate rapidly. Currently, there are no FDA-approved drugs for the control and treatment of this parasite, but several chemicals including organophosphates and diflubenzuron have been used with success.
The screening and quarantine of incoming fish is the best way to avoid a facility-wide Argulus infestation. Fish lice Argulus spp are members of a large group of branchiuran crustaceans that infest and cause disease in fish.
More than different species of Argulus are distributed worldwide. Argulus spp can be a major threat to fish health. Heavy infestations of this parasite can cause significant morbidity and mortality. The room into which the fish were received contained 2 self-contained, recirculating, aquatic rack systems, one to supply fish for research and the other to hold incoming fish.
These systems each comprise six to gallon tanks using a multistage filtration process and UV sterilization of filtered water. The filters include a mechanical-fiber pad, a fluidized bed biofilter, and a mechanical—chemical fiber sleeve with carbon.
The room is on a h light:dark cycle. All new arrivals are quarantined for at least 3 wk. When the research tank is depopulated, the fish in the quarantine system are used for research, and new fish are received into the previous research system.
Gross examination of the fish revealed that the shadow was a live organism resembling a fish louse. This organism was removed with forceps and placed in a beaker of tank water. Manual inspection of the other 8 fish cohoused with the index fish disclosed lice on the anal fins of 2 additional goldfish Figure 1. These parasites were removed and placed in the beaker with the first specimen. All remaining fish in the system were inspected visually, and no other parasites were seen.
The infected goldfish parasitized with lice did not demonstrate any clinical signs and therefore were placed back into tanks. A pathologist confirmed the organism to be A. Because our facility did not have a severe outbreak, and only a few fish were affected, we opted for the conservative approach of manual removal of lice without further medical intervention. After the lice had been removed, all goldfish in the affected system were monitored daily for evidence of adult Argulus; 10 mo later, no more fish lice were noted.
Chesapeake Bay Introduced Species Database
Email: ude. Argulus spp can be a major threat to fish health, because heavy infestations can cause significant morbidity and mortality. In addition, fish lice are known to be the vehicle for other fish diseases. During rounds at our facility, Argulus japonicus was collected from the caudal and anal fins of 3 goldfish Carassius auratus. These goldfish were asymptomatic, and no additional cases were noted after manual removal of the lice. As soon as any Argulus organisms are identified, management and treatment are recommended because infections can escalate rapidly.
References- Martin Economic Impacts Outside Chesapeake Bay Impact: Argulus japonicus is a potentially serious pest in aquaculture, including rearing of cyprinid fishes for food, baitfish rearing, ornamental culture of Carassius auratus and Cyprinus carpio Hoffman ; Jafri and Ahmed ; Rushton-Mellor The sites of attachment of the parasite can be unsightly and are also prone to secondary infection. High densities of Argulus spp. Argulus japonicus is apparently present in natural waters in much of North America Cressey ; LaMarre and Cochran , but its effects on wild fish populations are unknown. In some parts of the world, including South Africa, it has become an abundant parasite of native cyprinid fishes Shafir and Oldewage , but its impacts on fisheries have apparently not been quantified. References- Cressey ; Hoffman ; Jafri and Ahmed ; LaMarre and Cochran ; Rushton-Mellor ; Shafir and Oldewage Ecological Impacts Impacts on Natives: Parasitism Parasitism- Argulus japonicus punctures the skin of fishes, and secretes protoelytic enzymes to stimulate blood flow in the surrounding tissues.