title: Triploid and diploid Atlantic salmon show similar susceptibility to infection with salmon lice Lepeophtheirus salmonis.
abstract: BACKGROUND
  Sea lice infection is the most expensive disease factor for Atlantic salmon sea-cage farming. For triploid salmon to be accepted as a commercial possibility, investigation of susceptibility of triploid salmon to sea lice infection is a fundamental milestone. The susceptibility of diploid and triploid salmon to infection with Lepeophtheirus salmonis was examined in a tank trial in Scotland, a tank trial in Norway and a cage trial in Scotland.
  
  
  RESULTS
  Following a single infection challenge, results indicated a significant correlation between fish size and the number of attached sea lice. Triploid fish were larger than diploids at the smolt stage. In the tank trials, no difference was found between infection levels on diploids and triploids after a single infection challenge. The tank trial in Scotland continued with a second infection challenge of the same fish, which also showed no infection differences between ploidies. A borderline correlation between first infection and re-infection intensity was found for PIT-tagged diploid salmon examined after each challenge. No significant difference in louse infection between diploid and triploid salmon (∼2 kg) was found in the cage trial undertaken under commercial conditions.
  
  
  CONCLUSIONS
  This study concludes that triploid Atlantic salmon are not more susceptible to sea louse infection than diploid fish.
authors: Institute of Aquaculture, University of Stirling, Stirling, Scotland, UK.
authors: Benedikt
authors: B
authors: Frenzl
authors: Herve
authors: H
authors: Migaud
authors: Per Gunnar
authors: PG
authors: Fjelldal
authors: Andrew P
authors: AP
authors: Shinn
authors: John F
authors: JF
authors: Taylor
authors: Randolph H
authors: RH
authors: Richards
authors: Kevin A
authors: KA
authors: Glover
authors: David
authors: D
authors: Cockerill
authors: James E
authors: JE
authors: Bron
mesh_terms: D000818:Animals; D033342:Copepoda / Q000502:physiology; D004171:Diploidy; D005393:Fish Diseases / Q000469:parasitology*; D009664:Norway; D020317:Salmo salar / Q000235:genetics* / Q000469:parasitology*; D012606:Scotland; D057885:Triploidy
keywords: abundance; infection challenge; ploidy; sea lice