Longitudinal survey of flavobacterium species in icelandic salmonid fish farms

Thorbjorg Einarsdottir*, Gudbjorg Guttormsdottir, Daniel Connaghan, Sigridur Hjartardottir

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Flavobacterium species cause significant disease in salmonid farming worldwide, typically seen as mortality in sac fry and later as necrosis and ulceration in fingerlings and fry. In this study, we sampled Atlantic salmon Salmo salar and Arctic char Salvelinus alpinus from 5 Icelandic fish farms in 2014 and 2017, where flavobacteria were suspected to cause disease. The objective of the study was to identify and characterise the bacteria by sequencing the 16S rRNA gene and multilocus sequence type housekeeping genes. We found 5 distinct groups of flavobacteria: 3 that were homogeneous and appeared to persist in the fish farms between 2014 and 2017 and 2 that were heterogeneous and transient. Flavobacterium psychrophilum could be isolated from diseased Arctic char from all 5 fish farms in both 2014 and 2017. However, while the other 4 Flavobacterium sp. groups were isolated from Atlantic salmon, water and roe, F. psychrophilum could not be isolated from these samples. This indicates that flavobacteria other than F. psychrophilum may be the primary cause of fin and tail rot in Icelandic Atlantic salmon fry.

Original languageEnglish
Pages (from-to)15-24
Number of pages10
JournalDiseases of Aquatic Organisms
Volume141
DOIs
Publication statusPublished - 2020

Bibliographical note

Funding Information:
Acknowledgements. We thank the fish farmers who participated in the study. This work was supported by the AVS R&D Fund by the Ministry of Fisheries and Agriculture in Iceland (grant R 14 007-14).

Publisher Copyright:
© 2020 Inter-Research. All rights reserved.

Other keywords

  • 16S rRNA
  • Bacterial cold water disease
  • BCWD
  • Flavobacterium psychrophilum
  • MLST
  • Multilocus sequence typing

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