I
Ian Cloke
Guest
THE increase in new species farmed along the Norwegian coast is increasing the danger for spreading disease amongst the different fish species, according to a report in Fiskeriforskning.
With shorter distances between each farm, due to spatial constraints, the spreading of bacterial and viral diseases is allegedly a possibility.
In collaboration with the Norwegian College of Fishery Science, Fiskeriforskning has now tested this possibility on salmon, cod and halibut.
"We still do not know much about which diseases the new farmed species can catch, but we do know that several known bacteria and viruses can cause disease in many different fish species", says Senior Scientist Vera Lund.
"We have now studied this in a tank system especially designed for these studies at Troms? Aquaculture Research Station. Here, we can inflict a bacterial or viral disease on one type of fish in a central tank. From this tank, different quantities of infected waste water can be transferred to tanks with other species to see whether these are susceptible to the disease", explains the scientist.
The system has been tested by transmitting classical vibriosis from salmon to cod. Forty to sixty per cent mortality has been registered in the tanks with cod, depending on how much infected water was transferred, according to the research.
"Atypical furunculosis is a problem in halibut farming and an increasing problem in cod farms. Our tests showed that wastewater from a tank containing halibut with atypical furunculosis, transmitted the disease to cod in neighbouring tanks. The cod had a more chronic form of the disease than that which we had observed with other challenge models.
"Since neither cod nor halibut are vaccinated against atypical furunculosis, it is also possible that cod can infect halibut in a nearby farm. In addition, we do not know for certain whether salmon that are vaccinated against typical furunculosis are protected against all variants of the atypical furunculosis bacteria that are found in the environment."
It is important to develop effective vaccines for new farmed species before the disease problems become too serious. The challenge model proves the possibility for spreading, but does not say anything about the distances to which the disease can spread.
For more information, contact Senior Scientist Vera Lund on (+47) 77 62 92 19 or Scientist Helene Mikkelsen directly on (+47) 77 62 90 55.
With shorter distances between each farm, due to spatial constraints, the spreading of bacterial and viral diseases is allegedly a possibility.
In collaboration with the Norwegian College of Fishery Science, Fiskeriforskning has now tested this possibility on salmon, cod and halibut.
"We still do not know much about which diseases the new farmed species can catch, but we do know that several known bacteria and viruses can cause disease in many different fish species", says Senior Scientist Vera Lund.
"We have now studied this in a tank system especially designed for these studies at Troms? Aquaculture Research Station. Here, we can inflict a bacterial or viral disease on one type of fish in a central tank. From this tank, different quantities of infected waste water can be transferred to tanks with other species to see whether these are susceptible to the disease", explains the scientist.
The system has been tested by transmitting classical vibriosis from salmon to cod. Forty to sixty per cent mortality has been registered in the tanks with cod, depending on how much infected water was transferred, according to the research.
"Atypical furunculosis is a problem in halibut farming and an increasing problem in cod farms. Our tests showed that wastewater from a tank containing halibut with atypical furunculosis, transmitted the disease to cod in neighbouring tanks. The cod had a more chronic form of the disease than that which we had observed with other challenge models.
"Since neither cod nor halibut are vaccinated against atypical furunculosis, it is also possible that cod can infect halibut in a nearby farm. In addition, we do not know for certain whether salmon that are vaccinated against typical furunculosis are protected against all variants of the atypical furunculosis bacteria that are found in the environment."
It is important to develop effective vaccines for new farmed species before the disease problems become too serious. The challenge model proves the possibility for spreading, but does not say anything about the distances to which the disease can spread.
For more information, contact Senior Scientist Vera Lund on (+47) 77 62 92 19 or Scientist Helene Mikkelsen directly on (+47) 77 62 90 55.