A preliminary study of parasites and diseases of perch in an intensive culture system

Abstract

The recent development of intensive rearing of European perch Perca fluviatilis in warm water effluents revealed important pathological problems. This study gives a preliminary overview of parasites and diseases encountered in experimental perch farming. No virus has been recorded since the beginning of the experiments in 1993. By contrast, mass mortality caused by bacterial disease alone or associated with other pathogens were frequently observed. The main identified bacterial species were: Aeromonas sp., A. veronii, A. hydrophila, Streptococcus sp., Staphylococcus sp., Vibrio fluviatilis and Enterobacter agglomerans. Protozoans were the most common parasites observed on cultured P. fluviatilis. High mortality rate due to Ichthyobodo necator and Trichodina sp. may take place at different stages of perch rearing. In contrast, the infestation by Ambiphrya sp. and Heteropolaria sp. was size‐ or age‐related; these two ciliates infested perch weighing < 1 g and > 20 g, respectively. In spite of the presence of other parasites such as Ichthyophthirius multifiliis, Hexamita spp., Gyrodactylus sp. and Argulus sp. in the rearing system P. fluviatilis does not appear to be affected. Further abnormalities or diseases inherent to intensive culture systems are also described.

Intensive culture of juvenile and adult Eurasian perch (P. fluviatilis): effect of major biotic and abiotic factors on growth

“…Survival rates could be increased by: a) improving the quality of weaned juveniles and their resistance to handling stress and pathologies, which can be achieved through two complementary axes; b) improving the quality of eggs and larvae by giving the broodstock an appropriate diet (Abi-Ayad et al 1996) and using more adapted larval rearing technology such as rearing in 'green water' tanks (Brown et al 1989;Lavens et aI. 1994); c) using Final stocking biomass: 31,34 and 31kg -'(after Mélard et al 1995b) recirculating systems to minimize hazards from pathologies ; tailoring the quality of the diet to the precise nutritional requirements of perch, essentially with respect to fatty acid content to minimize the risks of hepatic degeneration (Grignard et al 1996) and lower resistance to pathologies. Higher growth rates and lower size heterogeneity could be achieved through the production of a monosex female population (Malison et al 1986) or sterile triploïd fish (Malison et al 1993;Malison, 1995).…”

Analysis of genetic variability within Argulus japonicus from representatives of Africa, Middle East, and Asia revealed by sequences of three mitochondrial DNA genes

“…Argulus sp. is found also in many European freshwater lakes (Valtonen et al 1997) and fish farms (Buchmann and Uldal 1995;Grignard et al 1996). A. japonicus has been extensively studied by several scientists either physiologically or morphologically using light microscopy and SEM (Kyosuke and Toshiki 1997;Avenant-Oldewage and Swanepoel 2006).…”

Culture Methods of Eurasian Perch and Yellow Perch Early Life Stages

“…Consequently, survival is significantly higher at 17°C but growth rate is 70 % lower than at 23°C ( Table 9.2). More frequent pathologies, mainly parasites (Grignard et al 1996), also induce higher mortality at 23°C.…”