Gill pathology in farmed salmon associated with the jellyfish Aurelia aurita

JELLYFISH-mediated damage to salmon and other species in aquaculture is a periodic challenge, which is considered by some workers to be increasing in frequency (Graham 2001, Purcell and others 2007, Rodger and others 2011). Significant pathology in affected fish has been observed in the gills and is considered to be due to the toxic effects of jellyfish venom via nematocyst discharge (Helmholz and others 2010, Rodger and others 2011). It has recently been suggested that certain jellyfish species may also act as vectors for Tenacibaculum maritimum (Ferguson and others 2010, Delannoy and others 2011), a bacterium frequently associated with gill pathology and the causal agent of tenacibaculosis. A number of jellyfish species have been implicated in fish kills over the years including the hydromedusae Phialella quadrata (Bruno and Ellis 1985) and Solmaris corona (Hay and Murray 2008), the siphonophores Muggiaea atlantica (Fossa and others 2003) and Apolemia uvaria (Bamstedt and others 1998), the scyphomedusae Cyanea capillata (Bruno and Poppe 1996), Pelagia noctiluca (Doyle and others 2008) and Aurelia aurita (Bruno and Poppe 1996). However, little descriptive information on the pathology and pathophysiology of jellyfish-mediated damage to fish has been published to date. This short communication describes the clinical impact of a jellyfish bloom on a finfish farm on the …