Control of freshwater fish louse Argulus coregoni: a step towards an integrated management strategy

Abstract

Harmful infections by ectoparasites of the genus Argulus occur repeatedly in freshwater fish farming operations where the management has largely been ineffective. Preventative methods and regular monitoring are rarely applied, so that chemical interventions become necessary. According to the Integrated Pest Management (IPM) approach, a sustainable management or control program for a parasite should be based on knowledge of the ecology of the parasite along with adoption of several prevention and control methods, the application of which is dependent upon the prevailing infection level. The application of multiple management tactics is especially important because parasites can develop resistance to chemical treatments. We took a step towards sustainable management of Argulus populations and tested the effect of several types of treatments on survival of A. coregoni at different stages in its life cycle. Parasite juveniles and adults were highly sensitive to potassium permanganate treatments (0.01 g l -1), which lead to 100% mortality, whereas treatments with formalin (0.6 ml l ) or malachite-green/formalin were not effective. Mechanical treatment by shaking infected fish in a hand net was an effective means of detaching parasites from the fish, and resulted in > 80% decreases in parasite numbers. Compared to eggs in control treatments, both drying over a minimum period of 24 h and formalin treatments (120 ml l ), did not significantly affect the viability of eggs. Based on the present results and previously published papers, we present an initial framework showing how A. coregoni populations could be managed effectively. KEY WORDS: Integrated pest management · IPM · Control · Prevention · Parasite · Argulus coregoni · Fish louse Resale or republication not permitted without written consent of the publisherDis Aquat Org 82: [67][68][69][70][71][72][73][74][75][76][77] 2008 sive or both, and do not always prevent economic losses. The majority of management protocols have relied on the use of chemicals either as oral medications or bath treatments (e.g. Costello 1993Costello , 2006. For example, the in-feed medication SLICE ® (emamectin benzoate; Schering-Plough Animal Health) has been used to control many crustaceans, e.g. Lepeoptheirus salmonis in seawater aquaculture, Salmincola edwardsii and Argulus coregoni in freshwater aquaculture (Stone et al. 2000, Duston & Cusack 2002, Hakalahti et al. 2004a. Alternative methods are, for example, fallowing farm sites between stockings (Bron et al. 1993), use of cleaner fishes (Treasurer 2002) and removal of specific life-cycle stages from the parasite populations (Gault et al. 2002, Hakalahti et al. 2004b). The emergence of reduced sensitivity to chemical treatments with increased doses applied to control parasites, however, has lead to concerns about the sustainability of the industry (e.g. Jones et al. 1992), and consequently to the adoption of the Integrated Pest Management (IPM) concept into aquaculture (e.g. Sommerville 1998, Mordue (Luntz) & Pike 2002)....

Effect of aqueous extract of Azadirachta indica A. Juss (neem) leaf on oocyte maturation, oviposition, reproductive potentials and embryonic development of a freshwater fish ectoparasite Argulus bengalensis Ramakrishna, 1951 (Crustacea: Branchiura)

“…Moreover, the residuals of the synthetic pesticides have been consistently burdening the eco-toxicity (Costello et al 2001) day by day. Indiscriminate use of the insecticides very often leads to rapid development of resistance (Hakalahti-Sirén et al 2008), so control of pests and parasites is currently hindered by the small number of effective products available in the market (Jonsson and Piper 2007). In this context, it is to be mentioned that different plant derivatives can be better alternatives and safer (De Albuquerque et al 2007;Dos Santos et al 2011;Banerjee and Saha 2013) for management of diseases of domesticated animals.…”

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“…Se llevó a cabo un tratamiento de eliminación de los parásitos por la técnica de remoción mecánica (RM) frotando a los peces con las mallas de captura (Hakalahti-Sirén et al, 2008) y además con agua a presión, tratando de dañar lo menos posible a los organismos. Los peces desparasitados (299) fueron colocados en un estanque de geomembrana de 20 m 3 para su observación.…”

“…Hakalahti -Sirén et al, (2008) evaluaron diferentes tratamientos para eliminar A. coregoni y A. foliaceus de Oncorhynchus mykiss y Salmo trutta, incluyendo la remoción mecánica (RM) y diversos compuestos químicos como permanganto de potasio (0.01 g L -1 ), cloruro de sodio (0.6 ml L -1 ) y una solución de verde malaquita con formol (20 g L -1 ). Sus resultados demuestran que el permanganato de potasio provocó una mortalidad del 100 % del ectoparásito.…”

Anthelmintic efficacies of three common disinfectants and extracts of four traditional Chinese medicinal plants against Gyrodactylus kobayashii (Monogenea) in goldfish (Carassius auratus)

“…However, Straus and Griffin (2001) demonstrated that the exposure to 0.9 mg/L potassium permanganate for 4 h resulted in over 95% mortality of Ichthyophthirius multifiliis theronts, and the dose of 1.0 mg/L could prevent the initial infestation of juvenile channel catfish and blue tilapia by this parasite. Hakalahti-Siren et al (2008) also reported that both juvenile and adult fish lice Argulus coregoni were highly sensitive to potassium permanganate treatments, exposure to which for over 30 min resulted in 100% mortality at 10 mg/L. The discrepancy among these results indicated that insecticide activity of potassium permanganate is highly dependent on the concentration and parasite species.…”