The effect of light regimen on settlement patterns of sea lice, Lepeophtheirus salmonis , on Atlantic salmon, Salmo salar , post-smolts while taking into account fish size and fin erosion in a static tank system

Hamoutene, Dounia; Mitchell, Jeremy S.; Murray, Harry M.; Eaves, Alexandra A.; Kim, Marshall; Belley, Rénald; George, Sheldon

doi:10.1016/j.aquaculture.2016.08.026

Cited by 8 publications

(4 citation statements)

References 32 publications

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“…Initial settlement location is influenced by host swimming behaviour (Bui, Oppedal, Samsing, & Dempster, 2018b) and velocity (Genna et al, 2005), as well as light conditions (Genna et al, 2005; Hamoutene et al, 2016). Here, chalimus II stages were most abundant in the ventral‐anterior quadrant, consistent with tank studies finding that newly attached lice are most abundant on the fins and ventral aspect of Atlantic salmon (Bron, Sommerville, Jones, & Rae, 1991; Bui, Oppedal, et al, 2018; Genna et al, 2005; Samsing et al, 2015) and sea trout (Bjørn & Finstad, 1998).…”

Section: Discussionmentioning

confidence: 99%

Where art thou louse? A snapshot of attachment location preferences in salmon lice on Atlantic salmon hosts in sea cages

Bui

Oppedal

Nola

et al. 2020

Journal of Fish Diseases

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Problematic sea lice infestations on farmed Atlantic salmon (Salmo salar) have motivated extensive research and development into new methods to prevent, monitor and control sea lice. Most of these technologies require detailed information on the behaviour, spatial distribution and demography of lice on host fish. This study investigated how salmon lice (Lepeophtheirus salmonis) infestation density varies across the host's surface under sea cage farming conditions. Lice abundance, demography and attachment location were tracked over time, with repeated sampling of 300 individually tagged salmon across three replicate experimental sea cages. The data reveal clear differences in attachment locations according to sex and stage, but with an overall preference for the dorsal surface among mobile stages—dorsal head for adult females and dorsal‐posterior section for males and pre‐adults. Total lice abundance was highly variable between repeated measures of individual fish, consistent with frequent host‐switching or mortality. Total lice numbers also declined between sampling dates, likely due to handling, with lost mobile lice being almost exclusively adult males. As the distribution of sea lice on hosts is likely determined by numerous factors, future image‐based automated detection systems should be validated in settings that reflect the complex host–parasite interactions that occur in open farming systems.

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Section: Discussionmentioning

confidence: 99%

Where art thou louse? A snapshot of attachment location preferences in salmon lice on Atlantic salmon hosts in sea cages

Bui

Oppedal

Nola

et al. 2020

Journal of Fish Diseases

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“…2005), while Hamoutene et al . (2016) reported that 24‐h darkness affected the attachment location but not abundance of salmon lice.…”

Section: What Preventative Methods Are Available?mentioning

confidence: 99%

Prevention not cure: a review of methods to avoid sea lice infestations in salmon aquaculture

Barrett

Oppedal

Robinson

et al. 2020

Reviews in Aquaculture

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The Atlantic salmon aquaculture industry still struggles with ectoparasitic sea lice despite decades of research and development invested into louse removal methods. In contrast, methods to prevent infestations before they occur have received relatively little research effort, yet may offer key benefits over treatment‐focused methods. Here, we summarise the range of potential and existing preventative methods, conduct a meta‐analysis of studies trialling the efficacy of existing preventative methods and discuss the rationale for a shift to the prevention‐focused louse management paradigm. Barrier technologies that minimise host–parasite encounter rates provide the greatest protection against lice, with a weighted median 76% reduction in infestation density in cages with plankton mesh ‘snorkels’ or ‘skirts’, and up to a 100% reduction for fully enclosed cages. Other methods such as geographic spatiotemporal management, manipulation of swimming depth, functional feeds, repellents and host cue masking can drive smaller reductions that may be additive when used in combination with barrier technologies. Finally, ongoing development of louse‐resistant salmon lineages may lead to long‐term improvements if genetic gain is maintained, while the development of an effective vaccine remains a key target. Preventative methods emphasise host resistance traits while simultaneously reducing host–parasite encounters. Effective implementation has the potential to dramatically reduce the need for delousing and thus improve fish welfare, productivity and sustainability in louse‐prone salmon farming regions.

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“…Similarly, there is mixed evidence for the effect of light intensity on the attachment and host‐finding behaviour of sea lice. Experiments on L. salmonis have shown no light effect (Browman et al ., ; Hamoutene et al ., ) as well as both higher (Genna et al ., ) and lower copepodid settlement (Hevrøy et al ., ; Mordue & Birkett, ) under low light conditions. We could find no studies testing this with C. clemensi specifically although some studies on L. salmonis in Pacific Canada conduct infestation trials under dimmed‐light conditions (Jones et al ., ).…”

Section: Discussionmentioning

confidence: 99%

Oust the louse: leaping behaviour removes sea lice from wild juvenile sockeye salmon Oncorhynchus nerka

Atkinson

Bateman

Dill

et al. 2018

Journal of Fish Biology

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We conducted a manipulative field experiment to determine whether the leaping behaviour of wild juvenile sockeye salmon Oncorhynchus nerka dislodges ectoparasitic sea lice Caligus clemensi and Lepeophtheirus salmonis by comparing sea-lice abundances between O. nerka juveniles prevented from leaping and juveniles allowed to leap at a natural frequency. Juvenile O. nerka allowed to leap had consistently fewer sea lice after the experiment than fish that were prevented from leaping. Combined with past research, these results imply potential costs due to parasitism and indicate that the leaping behaviour of juvenile O. nerka does, in fact, dislodge sea lice.

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The effect of light regimen on settlement patterns of sea lice, Lepeophtheirus salmonis , on Atlantic salmon, Salmo salar , post-smolts while taking into account fish size and fin erosion in a static tank system

Cited by 8 publications

References 32 publications

Where art thou louse? A snapshot of attachment location preferences in salmon lice on Atlantic salmon hosts in sea cages

Where art thou louse? A snapshot of attachment location preferences in salmon lice on Atlantic salmon hosts in sea cages

Prevention not cure: a review of methods to avoid sea lice infestations in salmon aquaculture

Oust the louse: leaping behaviour removes sea lice from wild juvenile sockeye salmon Oncorhynchus nerka

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