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