Problems caused by isopod parasites in commercial fishes

Abstract

Crustaceans are found in every type of aquatic ecosystem, and there are species adapted to extremes of temperature, pressure, salinity, and even anoxia. Parasitic isopods are typically marine and usually inhabit the warmer seas. They are blood-feeding; several species settle in the buccal cavity of fish, others live in the gill chamber or on the body surface including the fins. Isopods can cause morbidity and mortality in captive fish populations. The damage of gill filaments thus was not only due to the feeding but also by the pressure exerted by the dorsal side of the parasite. Erosion of gill lamellae, damage of gill rakers and pale gills were the severe gross lesions observed as a consequence of isopod infestation. Infested fish exhibited histopathological anomalies such as tissue reactions, primarily associated with the formation of granulomas consisted of macrophages and epithelioid cells, which are occasionally surrounded by a thin rim of fibroblasts. A marked increase in the size of the parasite is associated with the development of marsupium full of juvenile parasite. The infestation usually pressure atrophy often accompanies the presence of larger parasites. They may lead to economic losses in commercial species of fish. Thus, treating fishes infected with isopods without treating their environment may only provide temporary relief. It is also important to recognize the potential for secondary infections associated with severe isopod infections.

Diversity of parasites in Curimata incompta (Curimatidae), a host from Amazon river system in Brazil

“…Cymothoids are parasites of fish, in both immature forms and adults, and they may cause damages in gill filaments, reducing the branchial surface area of the hosts (Rameshkumar and Ravichandran 2014). Only one individual of C. incompta had the gills and fins infested by B. patagonica, a cymothoid species common in fishes from the Amazon.…”

Branchial cymothoids infesting the marine food fishes of Malabar coast

“…Cymothoids comprise 40 genera with more than 380 species (Ahyong et al 2011) and they infest different parts of the fish body including buccal cavity, gill chamber, body surface and fins, or sometimes they burrow inside the host body (Trilles 1969;Brusca 1981). Their continuous feeding on host blood and fish tissues results the serious localized tissue damage or lesions, reduced growth, behavioral problems and in extreme cases death itself Trilles 1976, 1979;Brusca 1981;Grabda and Rokicki 1982;Brusca and Gilligan 1983;Colorni et al 1997;Horton and Okamura 2001;dos Santos Costa and Chellapa 2010;Rameshkumar and Ravichandran 2014). Physiological modifications of the chimic composition of the fish plasma (Romestand and Trilles 1979;Horton and Okamura 2003) have also been reported.…”

A new record of parasitic isopod for the Indian fauna (Mothocya karobran Bruce, 1986) from Strongylura strongylura in the Pazhayar region, Southeast coast of India

“…In the present study the following species are newly recorded as hosts from S.Strongylura. In India, within this group there are recognizably related species M.plagulophora was collected from the Hemiramphus far (Bruce 1986;Gopalakrishnan et al 2010;Ravichandran et al 2011) M.renardi from Strongylura leiura and Tylosurus crocodilus (Bruce 1986;Rameshkumar and Ravichandran 2013b) Mothocya sp. (Rameshkumar et al 2013).…”

“…The genus was not considered problematic other than uncertainty over the validity of the genus Irona (Monod 1923;Trilles 1968;Monod 1971). It is found in the various areas of India, Mothocya plagulophora reported from Chennai, Mandapam Camp (Bruce 1986), Paragipettai coast (Ravichandran et al 2011), Mothocya renardi from Cochin, Palk Bay, Pondichery (Bruce 1986), Parangipettai (Rameshkumar and Ravichandran 2013b) and Mothocya sp from Parangipettai (Rameshkumar et al 2013) and it mainly parasitizes the gill chamber of atherinomorph fishes of the families Hemiramphidae and Belonidae. Therefore, the present investigation was carried out to record the Mothocya karobran in Strongylura strongylura from the Pazhayar, with reference to its prevalence, location on the host, abundance and the intensity of the infection.…”