Subsea pipelines and wells installed to support the oil and gas industry represent some of the most extensive and numerous anthropogenic structures throughout global marine ecosystems. There remains a paucity of information on the habitat value of these structures for fishery target species and, as a result, little understanding of how decommissioning should be conducted to minimise impacts to populations of these economically...

Elucidation of the role of infectious agents putatively involved in gill disease is commonly hampered by the lack of culture systems for these organisms. In this study, a farmed population of Atlantic salmon pre‐smolts, displaying proliferative gill disease with associated Candidatus Branchiomonas cysticola, Ca . Piscichlamydia salmonis and Atlantic salmon gill pox virus ( SGPV ) infections, was identified. A subpopulation of...

Due to increasing resistance to chemical therapeutants, the use of ‘cleaner fish’ (primarily wrasse, Labridae, species) has become popular in European salmon farming for biocontrol of the salmon louse, Lepeophtheirus salmonis (Krøyer). While being efficient de‐licers, cleaner fish mortality levels in salmon cages are commonly high, and systemic bacterial infections constitute a major problem. Atypical furunculosis, caused by A...

Sequence variation in a region of the virulence array protein gene ( vapA ; A‐layer) was assessed in 333 (‘typical’ and ‘atypical’) isolates of the fish pathogenic bacterium Aeromonas salmonicida . Resulting similarity dendrograms revealed extensive heterogeneity, with nearly all isolates belonging to either of 14 distinct clusters or A‐layer types. All acknowledged A. salmonicida subspecies (except ssp. pectinolytica , from w...

This study describes a novel multilocus variable number tandem repeat analysis ( MLVA ) based on six variable number of tandem repeat ( VNTR ) loci for genotyping of 37 E dwardsiella piscicida (previously E dwardsiella tarda ) isolates from multiple sources. The number of alleles identified for each of the six VNTR loci ranged from 3 to 5 with VNTR loci 1 ( DI = 0.632) and 3 ( DI = 0.644), displaying the highest degrees of pol...

Summary Although the growth of bacteria has been studied for more than a century, it is only in recent decades that surface‐associated growth has received attention. In addition to the well‐characterized biofilm and swarming lifestyles, bacteria can also develop as micro‐colonies supported by structured environments in both food products and the GI tract. This immobilized mode of growth has not been widely studied. To develop...

Piscine mycobacteriosis causes losses in a number of fish species both in the wild and in aquaculture worldwide. Mycobacterium salmoniphilum infections have on several occasions been reported in farmed Atlantic salmon, Salmo salar L. The present study tested and confirmed the susceptibility of Atlantic cod, Gadus morhua L., an important yet relatively novel aquaculture species, to infection with M. salmoniphilum . Atlantic cod...

Multiple greyish‐white visceral nodules containing abundant rapidly growing and acid‐fast bacteria, subsequently identified as Mycobacterium salmoniphilum, were detected in moribund and newly dead market‐sized fish during a period of increased mortality in an Atlantic salmon, Salmo salar , farm in western Norway. Isolates cultured from diseased fish were phenotypically consistent with Mycobacterium sp. previously isolated from...

Intracellular inclusions containing chlamydia‐like organisms are frequently observed in the gill epithelial cells of Atlantic salmon, Salmo salar L., cultured in fresh water in Ireland. In this study, the causative agent was identified in four separate freshwater sites, using 16s rRNA sequencing, as ‘ Candidatus Clavochlamydia salmonicola’. Histopathology and real‐time (RT) PCR were used to further assess infections. The preva...

Piscirickettsia salmonis is the causative agent of piscirickettsiosis, a transmissible disease of salmonid fish. Diagnosis of piscirickettsiosis has traditionally been based upon identification of typical pathological changes by histological investigation, with confirmation by immunohistochemistry on formalin‐fixed, paraffin‐embedded tissues. However, implementation of more rapid confirmatory techniques, preferably with higher...

The possible influences of contaminant bacteria, Pseudomonas fluorescens , infectious pancreatic necrosis virus (IPNV) and environmental stress on the development of vaccine‐related peritoneal adhesions in Atlantic salmon, Salmo salar L., pre‐smolts were investigated. Groups of 50 fish (≈ 30 g) vaccinated with a commercial, triple valent, metabolizable oil‐adjuvanted vaccine were pre‐injected with IPNV, co‐injected with Pseudo...