Economical impact and risk management effects of VHS (Viral haemorrhagic septicemia) on fish farming in Finland

VHS, among other fish diseases, may have large impact on fish farming profitability. VHS is economically one of the most significant fish diseases in European Rainbow trout farming. VHS virus (VHSV) may cause high mortalities and therefore losses and other costs for production. For the fish farming livelihood, it is important that the virus does not spread extensively throughout the industry.

In connection with the first incidences of VHS, the Finnish government paid compensation for the losses of the biosecurity program to the fish farmers. However, the disease spread rapidly and the government was forced to consider other options to oppose the virus. The Finnish Food Safety Authority (Evira) in cooperation with the Finnish Game and Fisheries Research (FGFRI) Socio-Economic Unit started evaluating a more practical and economical biosecurity program against VHS.

Results and conclusion

The mortality caused by VHSV varied between farms from zero to almost half of production population. It was noted that mortality increased due to various stress factors when the temperature fell below 14ºC. Because of the cold water mortality, the economic impacts are strongest in those production cycles where the fishes are at harvest size during the cold water season.

In Finland, decontamination breaks in infected units are conducted during normal production breaks, after fishes are send to harvest or transferred to the next unit. Therefore, the economic effects of decontamination are minor. However, if the biosecurity program affects annual production volumes, it has large impact on fish farmers’ profitability. In this sense, it would be reasonable to have secondary production sites if the breaks were to last longer. If mortality affects fingerlings, it is generally profitable to maintain capacity with new fingerling purchases if eligible available.

If the risk is managed by decentralizing farming units, it decreases the efficiency of production due to investment in new units and added daily variable costs. The economic risk represents a tradeoff between location costs and the effects of the disease on profitability.

Immediate harvesting after realizing the first VHS mortalities is economically justified if the market price does not collapse and mortalities rise high. However, in our simulation we noticed that even if the mortalities rise above 30%, the better market price in the late winter and spring overcomes the costs of mortalities. Due to the market price, it also makes no sense to change the production cycle so that the effects of VHSV cannot affect production, i.e. to keep up production during the cold water season.

The price of fingerling is economically important factor, if the size of the fingerling is large. It is possible to avoid the infection by purchasing fingerlings from producers whose biosecurity is well managed. However,the fingerling procurement price may be more expensive. Likewise in the case that the fingerling production is for the biosecurity reasons located far away from edible farming, the transport costs will raise the price of the fingerlings.

In conclusion, the effects of VHS can be fatal to small, one-production-unit farmers, where the effects concern the entire production. In larger companies, risk is decentralized to several units. However when risk is managed by decentralizing the units, the unit production volume has to be large to maintain the production efficacy. Nowadays, VHSV influence or the restrictive area encompasses about 4,000 tonnes of edible rainbow trout production. Along with the virus, the economic effects have expanded, making biosecurity management economically essential to industry.

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