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Laboratory and field investigations of salmon lice [ Lepeophtheirus salmonis (Krøyer)] infestation on Atlantic salmon ( Salmo salar L.) post‐smolts
Author(s) -
Finstad B,
Bjørn P A,
Grimnes A,
Hvidsten N A
Publication year - 2000
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1046/j.1365-2109.2000.00511.x
Subject(s) - lepeophtheirus , salmo , biology , fishery , infestation , hatchery , fish <actinopterygii> , salmonidae , zoology , agronomy
Hatchery‐reared 1‐year‐old Atlantic salmon post‐smolts ( Salmo salar L.), artificially infected with salmon lice [ Lepeophtheirus salmonis (Krøyer)] copepodids, were found to suffer from primary alterations (increased cortisol levels) at early lice stages. Secondary alterations, such as osmotic stress (increased chloride levels), first occurred after the preadult stages of the lice appeared. Fish with the highest salmon lice infections died throughout the experiment. Seven years of field investigation of Trondheimsfjorden showed that Atlantic salmon post‐smolts descending coastal waters can become heavily infected with salmon lice. The migrating post‐smolts were only infected with the chalimus stages, showing that the fish had only recently left the rivers. The infection level, however, varied considerably between the years, and, in 1998, the infection was higher than previous years. The experimental results have been combined with the field data to appraise the consequences of the infection.