Distribution of Neoparamoeba sp. in sediments around marine finfish farming sites in Tasmania

Abstract

Marine sediment samples collected from various sites at 2 Atlantic salmon farms in Tasmania were analysed for the presence of Neoparamoeba sp., an amoeba associated with amoebic gill disease (AGD) in farmed Atlantic salmon. Environmental variables of the sediment layer at each site, including redox potential and sulphide concentration, were measured and the general biological condition assessed by video observation. Sediments and environmental data were collected on 4 occasions at each site over a 12 mo period. Neoparamoeba sp. was detected in populations of amoebae recovered by culture from all sites and in 50% of all sediment samples taken. There was evidence of a seasonal influence on the presence of the amoeba, but this was different at each farm. No Neoparamoeba sp. was recovered from any sites at Farm 1 during the winter of 2002 whereas at Farm 2 this was the case for the summer of 2003. There appeared to be no relationship between the presence of Neoparamoeba sp., salmon farming activities and environmental parameters. KEY WORDS: Neoparamoeba · Amoebic gill disease · AGD · Marine sediments · Environmental parametersResale or republication not permitted without written consent of the publisher

Detection of serum anti‐Neoparamoeba spp. antibodies in amoebic gill disease‐affected Atlantic salmon Salmo salar

“…These were N. pemaquidensis (NP251002) (Morrison et al , 2005) isolated from AGD‐affected Atlantic salmon and N. branchiphila (SEDMH1) isolated from the sediment of Macquarie Harbour, Tasmania. Amoebae were maintained on seawater malt‐yeast agar as described by Crosbie et al (2005).…”

PCR survey for Paramoeba perurans in fauna, environmental samples and fish associated with marine farming sites for Atlantic salmon (Salmo salar L.)

“…Few studies have focused on introduction and transmission of P. perurans. Neoparamoeba pemaquidensis, previously considered to be the aetiological agent of AGD, was identified in biofouling, microbial biofilm layers, sea water, sediments and marine invertebrates, either by immunofluorescent antibody test or by culturing (Tan, Nowak & Hodson 2002;Crosbie, Nowak & Carson 2003;Douglas-Helders et al 2003;Crosbie et al 2005;Dykova et al 2005). For P. perurans, a preliminary PCR survey for potential reservoirs tested 22 samples of organisms (eight Caprella sp., two Mytilus sp., two anemones, one urchin, two sponges, five macroalgae and two swabs samples of periphyton), 27 sediment samples and 20 salmon lice (Lepeophtheirus salmonis (Krøyer)) and only the carapace of the lice were found positive for P. perurans (Nowak, Bryan & Jones 2010).…”

Reservoirs and alternate hosts for pathogens of commercially important crustaceans: A review

“…Other pathogenic amoebas have been isolated from water and sediment samples (Crosbie et al, 2005;Sawyer, 1977), so, while these species are not known to infect crustaceans, the potential exists that infective amoebas exist in the natural environment and await discovery (Sawyer, 1990).…”