Acute lion's mane jellyfish, Cyanea capillata (Cnideria: Scyphozoa), exposure to Atlantic salmon (Salmo salar L.)

Abstract

Jellyfish-induced gill pathology relies upon occasional diagnostic observations yet the extent and impact of jellyfish blooms on aquaculture may be significant. Idiopathic gill lesions are often observed in apparently healthy fish. This study exposed Atlantic salmon (Salmo salar L.) smolts to macerated Cyanea capillata at 2.5 and 5 g/L for 2 hr under controlled laboratory conditions. Blood chemistry and gill histopathology were examined over a subsequent 4-week period. Fish showed an acute response to the presence of jellyfish, including characteristic external "whiplash" discoloration of the skin and acute increases in blood electrolytes and CO concentration; however, these were resolved within 4 days after exposure. Histopathologically, gills showed first an acute oedema with epithelial separation followed by focal haemorrhage and thrombus formation, and then progressive inflammatory epithelial hyperplasia that progressively resolved over the 4 weeks post-exposure. Results were consistent with the envenomation of gills with cytotoxic neurotoxins and haemolysins known to be produced by C. capillata. This study suggests that many focal hyperplastic lesions on gills, especially those involving focal thrombi, may be the result of jellyfish stings. Thus, the presence of jellyfish and their impact may be severe and understated in terms of marine fish aquaculture and fish welfare.

Naut Your Everyday Jellyfish Model: Exploring How Tentacles and Oral Arms Impact Locomotion

“…Coupling these ideas with the COT data, lesser numbers of and shorter tentacles/oral arms suggest that these jellyfish may be better and more efficient active hunters (predators) than its jellyfish counterparts with more and longer tentacles/oral arms. One example of this could be box jellyfish (Carukia barnesi) rather than a jellyfish with longer tentacles, such as the lion's mane (Cyanea capillata) [38][39][40]. The decreases in forward swimming speeds may be attributed to suppressed vortex formation and ring dynamics, as suggested previously in Figure 7 and now Figure 17.…”

“…The large diversity of jellyfish tentacle/oral arm morphology, leads to a variety of different modes of predation among different jellyfish species. For example, some jellyfish actively hunt for food, like box jellyfish [38], while others are more passive and opportunist predators, hoping that their food (prey) gets caught in their tentacles/oral arms, like a Lion's Mane jellyfish [39,40]. Some species even use a combination of photosynthesis and passive filter-feeding for sustenance, e.g., the upside-down jellyfish [41,42].…”

A cohort study of gill infections, gill pathology and gill‐related mortality in sea‐farmed Atlantic salmon (Salmo salar L.): A descriptive analysis

“…Vascular lesions are unspecific responses and are not characteristic of a particular insult. An increase in prevalence and severity of thrombi, haemorrhage and/or aneurysms have been reported after non‐medicinal delousing and in situ net washing, and haemorrhage, thrombi and aneurysms have been observed after exposure to jellyfish (Baxter, Sturt, et al, 2011; Baxter, Rodger, McAllen, & Doyle, 2011; Bloecher et al, 2018; Marcos‐Lopez, Mitchell, & Rodger, 2016; Mitchell, Baxter, & Rodger, 2011; Østevik et al, 2021; Østevik et al, 2022; Powell, Atland, & Dale, 2018).…”

Elevated Seawater Temperature and Infection with Neoparamoeba perurans Exacerbate Complex Gill Disease in Farmed Atlantic Salmon (Salmo salar) in British Columbia, Canada

“…Confirmation of one or more infectious etiologies for CGD is limited by an absence of controlled laboratory infection models, and the extent to which specific agents are causal of or consequential to gill pathology remains unclear. Cnidaria, including pelagic stages or sessile stages which have been released into net pens through the action of in situ net-washing, have also been associated with CGD-like gill damage in farmed salmon [ 28 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ]. However, more work is required to better define the ecological, environmental, and production factors which contribute to net-wash-effluent-induced gill pathology [ 39 ].…”