Alternative competitive strategies in juvenile Atlantic salmon (Salmo salar): evidence from fin damage

MacLean, Amanda; Metcalfe, Neil B.; Mitchell, David F.

doi:10.1016/s0044-8486(99)00333-6

Cited by 75 publications

(66 citation statements)

References 28 publications

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“…This could be the result of either using a more virulent strain or of the fact that, in the present study, salmonids were more susceptible to Tenacibaculum maritimum than turbot. Salmonids are competitive and will bite and harass each other when held in captivity (Mork et al 1999, MacLean et al 2000. The observed size difference of fish in each experiment would have contributed to this behaviour, which is likely to facilitate bacterial invasiveness, as damage to the epithelium would create a portal of entry for the bacteria to colonise and proliferate (Handlinger et al 1997).…”

Section: Discussionmentioning

confidence: 99%

Experimentally induced marine flexibacteriosis in Atlantic salmon smolts Salmo salar. I. Pathogenicity

Gelderen¹,

Carson²,

Nowak³

2010

Dis. Aquat. Org.

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Tenacibaculum maritimum causes marine flexibacteriosis in many cultured fish species, including Atlantic salmon Salmo salar in Tasmania, Australia. Several aspects of the pathogenicity of this bacterium were investigated in naive Atlantic salmon smolts using different isolates, growth conditions and doses to produce a model of infection. We found that T. maritimum is pathogenic to Atlantic salmon using either marine Shieh's or marine Ordal's culture medium. The use of aeration in broth culture produced a dose effect in challenge due to a 'clumping' of the bacteria during culture. The virulence of a strain appears to be connected with this 'clumping'; the more adherent the cells, the more pathogenic the strain. Differences in virulence between 3 strains was apparent, with 1 of the strains (89/4747) being non-pathogenic and unable to produce disease in the host. The 2 other strains (89/4762, 00/3280) were highly virulent, resulting in 100% mortalities within 3 d. A reproducible model of infection has been established in the present study using strain 89/4762. Results from the present study provide a better insight into the nature of the disease. KEY WORDS: Tenacibaculum maritimum · Pathogenicity · Atlantic salmon · Infection model Resale or republication not permitted without written consent of the publisherDis Aquat Org 91: [121][122][123][124][125][126][127][128] 2010 MATERIALS AND METHODSPathogenicity experiments. Three different methods were used to assess the pathogenicity of Tenacibaculum maritimum in Atlantic salmon (Table 1). Expt 1 was a comparison of methods: 2 different growth media, marine Shieh's broth (MSB) and marine Anacker and Ordal's broth (Anacker & Ordal 1959) (MOB), with or without aeration were used during culture of bacteria. The assessment was made with strain 89/4762. Expt 2 was a comparison of the pathogenicity of 3 strains (89/4762, 89/4747, 00/3280) and Expt 3 compared dose effects for 1 strain (89/4762). Assessments of culture media and strains on pathogenicity were made in a semi-static experiment. As a recirculation system was used in Expt 3, there were 2 different control treatments. One control treatment was within the recirculation system and was called control (in); and another was still part of the system but had a separate water source, and was called control (out). The system was set up with a filter bank down to 0.8 µm for incoming water and 2 UV lights (400 J m 2-1 , 4000 l h -1 ) to reduce bacterial load.Experimental fish. Naive, disease-free Atlantic salmon smolts were obtained from a commercial hatchery. The fish were initially kept in freshwater and then acclimated to seawater (salinity 35) over a week starting at salinity 5. They were fed on a commercial diet (Atlantic HP, Skretting) at maintenance (1% body weight) during acclimation. Feeding ceased 48 h before challenge. Numbers of fish and replicates, weight and length of the fish, and water conditions for each experiment are summarised in Table 2.Bacteria cultures. Three strains of Tenacibaculum marit...

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Section: Discussionmentioning

confidence: 99%

Experimentally induced marine flexibacteriosis in Atlantic salmon smolts Salmo salar. I. Pathogenicity

Gelderen¹,

Carson²,

Nowak³

2010

Dis. Aquat. Org.

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“…Bitting between individuals can indicate an implementation of social hierarchy (Moutou et al, 1998). Mainly it happen in the time of serving feed (Maclean et al, 2000;Linnér and Brännäs, 2001;Ellis et al, 2002;Stejskal et al, 2011), when dominant fi sh restrain access to food to inferior fi sh (Ellis et al, 2002). Dominant fi sh are mostly huge individuals (Lemm et al, 1988;Maclean et al, 2000).…”

Section: Aggressive Behaviourmentioning

confidence: 99%

“…Mainly it happen in the time of serving feed (Maclean et al, 2000;Linnér and Brännäs, 2001;Ellis et al, 2002;Stejskal et al, 2011), when dominant fi sh restrain access to food to inferior fi sh (Ellis et al, 2002). Dominant fi sh are mostly huge individuals (Lemm et al, 1988;Maclean et al, 2000). On the contrary, subordinate fi sh are smaller individuals and with reduced growth rate (Moutou et al, 1998).…”

Section: Aggressive Behaviourmentioning

confidence: 99%

“…There is an increase of probability of fi n damage with dominance of individuals because these individuals are fi ghting for food with Atlantic salmon (Salmo salar). On the contrary, smaller subordinate fi sh intake less feed, they are growing slowly and reduce the risk of confl ict with dominant individuals and fi n damage (Maclean et al, 2000). The dorsal fi n becomes damaged most frequently in salmonids (Bosakowski and Wagner, 1995;Maclean et al, 2000).…”

Section: Aggressive Behaviourmentioning

confidence: 99%

“…On the contrary, smaller subordinate fi sh intake less feed, they are growing slowly and reduce the risk of confl ict with dominant individuals and fi n damage (Maclean et al, 2000). The dorsal fi n becomes damaged most frequently in salmonids (Bosakowski and Wagner, 1995;Maclean et al, 2000). Flood et al (2012) observed by camera that the most attacks of big rainbow trout individuals were heading towards caudal fi n area of smaller individuals.…”

Section: Aggressive Behaviourmentioning

confidence: 99%

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