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| | [[Linguatula serrata|''Linguatula serrata'']] | | [[Linguatula serrata|''Linguatula serrata'']] |
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| − | | + | [[Sea Lice]] |
| − | ==Sea Lice==
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| − | [[Image:Sea Lice.jpg|right|thumb|200px|Sea Lice - Copyright Joseph G. Kunkel at The Kunkel Fish & Aquatic Invert Site]] | |
| − | *Economic importance to the fish farming industries
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| − | **Especially in North American and in Northern Europe
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| − | | |
| − | *''Lepeophtheirus'' is found only in the Northern hemisphere
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| − | | |
| − | *''Caligus'' is found worldwide
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| − | | |
| − | '''Recognition'''
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| − | | |
| − | *Males measure 6mm in length
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| − | | |
| − | *Females measure 1cm long
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| − | **Have a long egg sac
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| − | *5 pairs of legs
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| − | **3 pairs for swimming
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| − | **2 pairs modified for eating
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| − | | |
| − | *Brown to red in colour
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| − | | |
| − | *Similar in appearance to the horse shoe crab
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| − | | |
| − | '''Life Cycle'''
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| − | *Eggs released from long egg sacs into environment
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| − | | |
| − | *2 non-parasitic larval stages
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| − | *7 parasitic larval stages (nauplius)
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| − | **Copepod, chalimus and pre-adult
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| − | | |
| − | *Life cycle takes 3 weeks to 4 months depending on temperature
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| − | | |
| − | '''Epidemiology'''
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| − | *Largely found in salt water
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| − | | |
| − | *Most wild salmonids migrate to the sea for part of their life cycle
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| − | | |
| − | *Sealice numbers are low on wild salmonids (adults only)
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| − | *Sealice numbers are high on farmed salmonids (larvae and adults)
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| − | **90% prevalence
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| − | **Average of 5-10 sealice upon a single fish
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| − | **Most sealice found on dorsal fin, head and back and underside of tail and fins
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| − | **Adults survive for over 3 weeks
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| − | **Migration of larval stages can be up to 1km
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| − | **Larvae locate host by responding to changes in light and vibration
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| − | | |
| − | '''Pathogenesis'''
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| − | *Adults and larval stages are epidermal browsers
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| − | | |
| − | *Mouth tube of toothed ridges abrades fish epidermis
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| − | | |
| − | *Heavy infections leads to:
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| − | **Epidermal abrasion
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| − | **Haemorrhage
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| − | **Immunosuppression
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| − | **Decreased productivity
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| − | **Death
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| − | | |
| − | '''Control'''
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| − | *Ectoparasiticides
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| − | *Hidden antigen vaccine
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| − | *Wrasse which feed on sealice
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| − | | |
| − | *Management improvements
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| − | **E.g. ''All in, all out'' and 6 week fallowing
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| − | | |
| − | *Stock selection
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| − | **e.g. Selective breeding for resistance
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| | ==[[Crustacea Flashcards - WikiBugs|Crustacea Flashcards]]== | | ==[[Crustacea Flashcards - WikiBugs|Crustacea Flashcards]]== |
