July 21, 2016

Cermaq study finds potential impact of using lumpsuckers to fight salmon lice


Lumpsuckers, small scorpaeniform marine fish of the Cyclopteridae family, are being used in increasing numbers by the Norwegian salmon industry, including Cermaq, as a measure to control salmon lice, the company said.


Consequently, there is a need for increased knowledge of the biological challenges facing this species when cultured. Cermaq's R&D reportedly leads the way and has recently published new findings.


The use of cleaner fish as biological controls of salmon lice has increased significantly in the last decade in Norwegian salmon production. This alternative to chemical treatments has resulted in the emergence of lumpsucker (Cyclopterus lumpus L) hatcheries and culture facilities in Norway.


It has been demonstrated that the use of lumpsuckers can be an effective, biological approach for the removal of salmon lice, but it has also been revealed that there are a number of biological challenges (i.e. parasites and bacteria) related to the production and use of these fish.


A study performed by Cermaq's clinical scientists, Sverre Bang Småge, Kathleen Frisch and Øyvind Brevik, at Cermaq's R&D department in Bergen, Norway, describes the first finding of Tenacibaculum maritimum, a major fish pathogen worldwide, in cultured juvenile lumpsuckers in Norway.


The diseased fish examined in the study were lethargic and had skin lesions characterised by increased mucus production and the presence of whitish necrotic tissue, especially in the head region. Skin scrapings from these lumpsuckers revealed large amounts of bacteria closely related to T. maritimum, which was confirmed through sequencing and comparison to published T. maritimum isolates. Further analysis showed that the bacteria was closely associated with the pathology and therefore could be contributing to the disease and / or mortality.


A key question will be whether lumpsuckers may be a vector for pathogens that may cause disease in salmon, Cermaq concluded.


- Cermaq

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