Favourable conditions for the development of parasites include:
- high densities of fish: this context favoUrs the transfer of parasites from one fish to the other;
- the biofouling of farming systems due to the accumulation of organic wastes or fouling nets;
- contacts with wild animals.
Since many systems use water that has potentially already been contaminated by parasites, filtration systems are frequently used. While these can prevent a fish population from being contaminated by large pathogens, they are inefficient in blocking the smaller parasites.
Managing parasitical pressure is complex, as shown by the recent difficulties experienced by the more mature aquaculture salmon industry in attempting to contain sea lice invasion.
Many products that work against parasites can end up being toxic to farmed fish and / or the fish farmers who use them. The environmental impact of these products also poses serious problems, as do their potential effects on those who consume them when the withdrawal date has not been respected.
In addition, parasites are pathogens whose life cycles are often complex. A product that is efficient at a given stage of development can be completely powerless if used against the same parasite at another stage. When that happens, treatments can only temporarily decrease the pressure.
It is therefore often necessary to apply more or less prolonged bathing treatments. While these actions can be difficult in above-ground ponds they are often impossible to undertake on sea cages.
Feed additives are another promising avenue for managing parasite virulence. Some of them have in fact demonstrated their ability to reduce parasite pressure and / or delays in performance. The possibility of incorporating treatments in the feed can allow for avoiding the manipulation of toxic products.
The sharing and pooling of experiences among farmers can be beneficial, as it provides them the opportunity to learn from each other. Exchanges between producers, technicians, and experts involved in production chains can be successful as parasite problems often have regional impacts that have already been experienced by other farmers.
The Techna Group assists many farmers in their search for efficient methods of controlling parasite pressure. Our position at the upstream stage of the production process allows us to take a global approach to these problems. For more information please contact our experts!