National research needed to prevent disease in fish

24.3.2015

<p>The necessary information on the behaviour of different pathogens in Finland's conditions can only be obtained through research on fish diseases conducted in Finland. Finland's fish-health which is currently strong is now threatened by changing climate conditions and fish diseases introduced by imported fish. Experts gather to discuss the health of Finnish fish at the annual Fish Health Day organised by Finnish Food Safety Authority Evira and Finnish Fish Farmer's Association.&nbsp;</p>

The programme of Fish Health Day traditionally offers an overview of fish diseases, legislation and regulatory control. Other themes include recirculating farming and bacterial diagnostics. This year Fish Health Day is held in Tampere on 26 March, 2015.

Use of antibiotics reflects the status of bacterial disease

"The heat of last summer caused more bacterial fish disease than usual, which in turn increased the use of antibiotics in food-producing fish farms. Consequently, the use of antibiotics reached the levels of 2010, when the previous hot summer occurred. The high amount of antibiotics illustrates the complexities of the bacterial disease situation”, explains senior researcher, DVM Ph.D. Perttu Koski from Evira's Production Animal and Wildlife Health Research Unit.

The majority of medicated feed was used in fish farms in sea areas. Generally speaking, the use of antibiotics in fish farming in Finland is at a relatively low level, thanks to effective vaccination programmes and other measures.

Fast and accurate bacterial diagnosis made possible by a new instrument

Evira's research unit for veterinary bacteriology has been using the new MALDI-TOF MS technology for identifying bacterial isolates, including isolates from fish for a year now.

"The instrument identifies the majority of isolated bacteria in a fast, accurate and economic way. As a result, there has been a clear decrease in subculturing and in the use of traditional biochemical identification tests and test series”, says senior researcher Kirsti Pelkola from Evira’s Veterinary Bacteriology Research Unit.

Using recirculating aquaculture systems to tackle fish diseases

As the name suggests, recirculating farming is based on recirculating water, and is expected to increase fish production in Finland. Water recirculating techniques decrease eutrophication and it is therefore possible to use them for adjusting the environmental conditions in fish farms and treating fish diseases.

"Fish health and fish production can improve because recirculating aquaculture systems allow for a more accurate distribution of antibiotics and other medicines and their temperatures can be set to a level that is unfavourable to pathogens. This also allows for better water disinfection than traditional fish farming techniques. Recirculating aquaculture systems do, however, have their own challenges when it comes to fish health", clarifies researcher Anna Maria Eriksson-Kallio from Evira’s Production Animal and Wildlife Health Research Unit.

Animal disease legislation on fish diseases is up to date

New decrees and the decision given in the new Animal Diseases Act (Eläintautilaki, 441/2013) that entered into force in early 2014 have brought measures to prevent fish diseases up to date. For example nearly everyone working with fish and all laboratories are now obliged to report animal diseases to the authorities.

"The change in the legislation on bacterial kidney disease BKD in fish requires fish farmers to be alert. Authorities are no longer responsible for the prevention of BKD as it is now based on voluntary health monitoring. Regional State Administrative Agencies classify the fisheries participating the voluntary programme by their odds for not having BKD. The health classification comes in handy when trading to restock fish or do business with other fisheries either in Finland or abroad”, says veterinary officer Hanna Lounela from the Regional State Administrative Agency of Northern Finland.

Research project on recirculating farms and a press release about an international seminar on recirculating farming organised by Evira.

More information on the Finnish Fish Farmer's Association and the Fish Health Day (in Finnish).

More information on fish diseases:
Senior Researcher, Head of Section Perttu Koski, tel. + 358 40 569 4541

 

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