Experimental infections with Lepeophtheirus salmonis (Krøyer) on threespine sticklebacks, Gasterosteus aculeatus L., and juvenile Pacific salmon, Oncorhynchus spp.

Jones, Simon R. M.; Kim, E; Dawe, S. C.

doi:10.1111/j.1365-2761.2006.00742.x

Cited by 39 publications

(63 citation statements)

References 24 publications

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“…For example, a well-developed tissue response occurs at the site of louse attachment on coho salmon Oncorhynchus kisutch 1 d post infection, whereas the reaction is markedly reduced or absent in Chinook salmon O. tshawytscha and Atlantic salmon (Johnson & Albright 1992). Similarly, the intensity of L. salmonis was significantly lower on coho salmon when compared to Atlantic salmon and rainbow trout O. mykiss (Fast et al 2002), and pink salmon O. gorbuscha rejected L. salmonis more rapidly than chum salmon O. keta during laboratory challenges (Jones et al 2006(Jones et al , 2007. The rejection of lice observed in the latter study is associated with an earlier and quantitatively higher expression of proinflammatory genes in pink salmon (Jones et al 2007).…”

Section: Introductionmentioning

confidence: 93%

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Development of the salmon louse Lepeophtheirus salmonis and its effects on juvenile sockeye salmon Oncorhynchus nerka

Jakob¹,

Sweeten²,

Bennett³

et al. 2013

Dis. Aquat. Org.

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Responses of sockeye salmon Oncorhynchus nerka during infection with Lepeophtheirus salmonis were assessed in controlled laboratory trials. Juvenile salmon were exposed to 100 copepodids fish −1 (Trials 1 and 2) or 300 copepodids fish −1 (Trial 3) at mean weights of approximately 40, 80 and 135 g, respectively. Infections occurred on all salmon in all trials, and mean abundances (infection densities) ranged between 3. At attachment sites on gills, we observed hyperplasia of basal epithelial cells and fusion of secondary lamellae occasionally associated with a cellular infiltrate. At attachment sites on fins, partial to complete skin erosion occurred, with limited evidence of hyperplasia or inflammation. Scale loss and abrasions coincided with pre-adult lice around 20 d post infection (dpi). Plasma osmolality was significantly elevated in exposed fish in Trials 1 (21 dpi), 2 (15 and 36 dpi) and 3 (20 dpi), whereas haematocrit was significantly depressed in exposed fish in Trials 1 (21 and 28 dpi) and 3 (20 dpi). Plasma cortisol was significantly elevated in exposed fish at 20 dpi (Trial 3). Physiological changes and mortality were related to the intensity of infection and became most prominent with pre-adult stages, suggesting patterns of infection and response in sockeye salmon similar to those reported for Atlantic and Chinook salmon.KEY WORDS: Sockeye salmon · Salmon lice · Physiology · Histopathology · Host response · SusceptibilityResale or republication not permitted without written consent of the publisher

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Section: Introductionmentioning

confidence: 93%

“…The water flow was stopped, tank volume was reduced to approximately 90 l, aeration was maintained, and the water was supplemented with 0.2 mg l −1 metomidate hydrochloride (Syndel Laboratories) as a sedative (Jones et al 2006). Copepodids were added to each tank as described below.…”

Section: Exposure To Lepeophtheirus Salmonismentioning

confidence: 99%

Development of the salmon louse Lepeophtheirus salmonis and its effects on juvenile sockeye salmon Oncorhynchus nerka

Jakob¹,

Sweeten²,

Bennett³

et al. 2013

Dis. Aquat. Org.

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“…In British Columbia, field surveys found that not only were juvenile pink and chum salmon infested, but 84 per cent of sticklebacks Gasterosteus aculeatus L. also were, of which 97 per cent were copepodite and chalimus stages (Jones et al 2006a). However, laboratory studies found a loss of lice on all three hosts over time, and no mature L. salmonis occurred on sticklebacks (Jones et al 2006b). Neither the source nor fate of these lice was known, but some may re-infest other fishes.…”

Section: Research Progress (A) Larval Dispersal and Transportmentioning

confidence: 99%

How sea lice from salmon farms may cause wild salmonid declines in Europe and North America and be a threat to fishes elsewhere

2009

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Fishes farmed in sea pens may become infested by parasites from wild fishes and in turn become point sources for parasites. Sea lice, copepods of the family Caligidae, are the best-studied example of this risk. Sea lice are the most significant parasitic pathogen in salmon farming in Europe and the Americas, are estimated to cost the world industry E300 million a year and may also be pathogenic to wild fishes under natural conditions. Epizootics, characteristically dominated by juvenile (copepodite and chalimus) stages, have repeatedly occurred on juvenile wild salmonids in areas where farms have sea lice infestations, but have not been recorded elsewhere. This paper synthesizes the literature, including modelling studies, to provide an understanding of how one species, the salmon louse, Lepeophtheirus salmonis, can infest wild salmonids from farm sources. Three-dimensional hydrographic models predicted the distribution of the planktonic salmon lice larvae best when they accounted for wind-driven surface currents and larval behaviour. Caligus species can also cause problems on farms and transfer from farms to wild fishes, and this genus is cosmopolitan. Sea lice thus threaten finfish farming worldwide, but with the possible exception of L. salmonis, their host relationships and transmission adaptations are unknown. The increasing evidence that lice from farms can be a significant cause of mortality on nearby wild fish populations provides an additional challenge to controlling lice on the farms and also raises conservation, economic and political issues about how to balance aquaculture and fisheries resource management.

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“…This sea louse occurs naturally on salmonids in the northern hemisphere, and it is not considered unusual for wild salmonids to carry a few individuals (Tingley et al 1997, Urquhart et al 2008. L. salmonis is largely specific to salmonids, and although infections have occasionally been reported in other groups of fish (Jones et al 2006a, these should be considered as unusual (Kabata 1979) and may not enable the parasite to complete its lifecycle (Jones et al 2006b). Among Norway, Scotland and Canada, L. salmonis costs the aquaculture industry approximately 70 million GBP per annum (Heuch et al 2005).…”

Section: Introductionmentioning

confidence: 99%

Reduced Lepeophtheirus salmonis larval abundance in a sea loch on the west coast of Scotland between 2002 and 2006

Penston¹,

Millar²,

Davies³

2008

Dis. Aquat. Org.

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A survey for planktonic sea louse larvae was carried out in Loch Shieldaig, Scotland, between 2002 and2006, and spanned 2 successive production cycles (Cycles 1 and 2) at a local Atlantic salmon Salmo salar L. farm. The vast majority of the caligid copepodids recovered were Lepeophtheirus salmonis; however, the methodology was unable to determine the species of the caligid nauplii. Greatest densities of nauplii were found at the sampling station adjacent to the salmon farm, and larval densities were low during the fallow period of both cycles. Peaks in nauplius densities occurred around the same time in the 2 cycles, but the peaks were significantly lower during Cycle 2 than Cycle 1. Lepeophtheirus salmonis copepodid densities varied temporally, but not spatially. During most of Cycle 2, copepodid densities were significantly lower than those recovered during Cycle 1. Numbers of gravid L. salmonis at the local salmon farm correlated significantly with densities of louse nauplii and L. salmonis copepodids in the water at time lags of 0 and 1 wk, and 1 and 2 wk, respectively. This survey demonstrated a reduction in densities of L. salmonis larvae in the plankton (an indication of L. salmonis infectious pressure) between the 2 cycles and indicated that the farm was an important source of L. salmonis larvae. The application of anti-louse treatments using emamectin benzoate reduced the numbers of gravid L. salmonis at the farm, and this was the main factor influencing the apparent reduction in L. salmonis infectious pressure in the loch between cycles. KEY WORDS: Lepeophtheirus salmonis · Sea lice · Larvae · Salmon farm · Scotland Resale or republication not permitted without written consent of the publisherDis Aquat Org 81: [109][110][111][112][113][114][115][116][117] 2008 duration of each stage of development is strongly dependent on temperature (Johnson & Albright 1991a). Under average sea surface temperatures in Loch Torridon (around 10°C), L. salmonis nauplii and copepodids would last approximately 3 and 8 d, respectively (Johnson & Albright 1991a), but may become less capable of finding a host after just a few days as finite energy reserves dwindle (Tucker et al. 2000).Few published accounts have described the behaviour of Lepeophtheirus salmonis larvae in the wild. Costelloe et al. (1998a,b) frequently recovered L. salmonis larvae near salmon farms in Ireland. They suggested that most of these larvae were probably of farm origin and that intermittent pulses of L. salmonis larvae that occurred near river mouths were probably of wild origin. A study in Loch Shieldaig, Scotland (Penston et al. 2008), suggested that the majority of louse larvae recovered near a salmon farm were the progeny of L. salmonis on farmed salmon. In contrast to Costelloe et al. (1998a,b), who concluded that farms only influence L. salmonis populations in their immediate environs, Penston et al. (2008) suggested that L. salmonis larvae can have a widespread effect in the surrounding waters.As with most salmon farms in Scotl...

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Experimental infections with Lepeophtheirus salmonis (Krøyer) on threespine sticklebacks, Gasterosteus aculeatus L., and juvenile Pacific salmon, Oncorhynchus spp.

Cited by 39 publications

References 24 publications

Development of the salmon louse Lepeophtheirus salmonis and its effects on juvenile sockeye salmon Oncorhynchus nerka

Development of the salmon louse Lepeophtheirus salmonis and its effects on juvenile sockeye salmon Oncorhynchus nerka

How sea lice from salmon farms may cause wild salmonid declines in Europe and North America and be a threat to fishes elsewhere

Reduced Lepeophtheirus salmonis larval abundance in a sea loch on the west coast of Scotland between 2002 and 2006

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