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A technique for the controlled incubation of largemouth bass eggs (Micropterus salmonides) has been demonstrated at the Warmwater Fish Cultural Development Center, Marion, Alabama [9]. During the search for an acceptable incubation method, occasional high mortality of embryos was encountered and attributed to disease. Since the brood fish from which the eggs were obtained had a history of chronic hemorrhagic septicemia caused by Aeromonas liquefaciens [8, 10], prophylaxis of the eggs by disinfection (a common practice in trout culture [3, 4, 5, 6 ]) seemed applicable. MATERIALS AND METHODS'The objective of this study was to determine which of the six readily available chemicals I previously used for trout egg disinfection would be best for protecting bass eggs against infection by A eromonas liquefaeiens.The two strains of A. liquefaeiens used to infect the bass eggs were from Auburn, and Marion, Alabama. Both were initially isolated from largemouth bass, and were maintained on trypticase soy agar (TSA) or in nutrient broth (NB).

In England and Wales, freshwater anglers have shifted their behaviour towards visiting catch-andrelease lake fisheries that are intensively stocked, mainly of large common carp, Cyprinus carpio L., to maintain high catch rates. Of 187 fish kills investigated in these intensively stocked lake fisheries in 2004 and 2005, most occurred between April and June and were mainly caused by parasitic or bacterial infections. Bacteria were usually associated with ulcerative diseases caused by strains of the bacterium Aeromonas salmonicida (Emmerich & Weibel) and secondary infections of opportunistic bacteria of the Genus Aeromonas (excluding salmonicida) and Pseudomonas. Parasites involved in fish kills included Ichthyophthirius multifiliis (Fouquet), Chilodenella sp., Ichthyobodo necator (Henneguy) and Argulus sp. Outbreaks were typically in fisheries with high extant stock densities (>1500 kg ha )1 ) and sub-optimal habitats, for example of low habitat heterogeneity with few macrophytes in the littoral zone. Recent stocking was also a key factor when only carp was affected. Thus, certain fisheries management practices that aim to enhance fishery performance may instead trigger fish kills during spring.K E Y W O R D S : bacteria, Cyprinus carpio, fisheries management, parasite, virus.

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