Many commercial fish farms are having an increasingly tough time keeping their fish healthy and alive, in large part due to the fact that their unnatural living conditions lead to a high prevalence of disease and death. But rather than change the ways in which they raise fish, many farms are instead seeking out quick fixes like fish vaccines, which are now being pushed on virtually all commercially raised fish.

A recent presentation put together by an aquatic veterinarian from Ireland reveals a plan to promote fish vaccination as a way to deal with the problem of fish disease. Though relatively novel, fish vaccines are already in widespread use in many parts of the world, and some fish experts would like to see the use of fish vaccines expand even further.

“Vaccination is the best method to increase survival rate and profitability in aquaculture when used in combination with several factors which are necessary to guarantee the highest possible survival rate,” explains Dr. Marian McLoughlin in one of her presentation slides.

Dr. McLoughlin believes that fish vaccines are an ideal way to deal with fish disease, because fish have an immune system similar to the type that humans have. She also admittedly believes the vaccine theory that bacteria, viruses and other forms of infection and disease can be prevented through the use of vaccinations, no matter their form.

In the case of fish, Dr. McLoughlin believes more work needs to be done to create an effective vaccine technology that can be quickly applied to large masses of fish. Current methods include traditional injection vaccination, immersion vaccination, spray vaccination and oral vaccination, each of which has its own pros and cons.

Aquatic vet says immersion vaccination important for producing ‘safe’ fish

But the most promising for its ease of administration and rapid turnaround is immersion vaccine, says Dr. McLoughlin, followed by injection and oral boosters as needed. Since many of the fisheries that rely on fish vaccinations still use injection vaccinations, which are difficult to administer and not very efficient, Dr. McLoughlin suggests that new strategies be employed to vaccinate more fish.

“Aquaculture needs effective and safe vaccines to be sustainable,” she insists. “Fish vaccinology is still a young and maturing science but amazing advances can be made. These need to be translated into licensed products.”

As far as which countries currently use the most fish vaccines, the U.S. tops the list with somewhere around 30 fish vaccines presently approved for use. Norway, on the other hand, which is the world’s largest producer of farmed salmon, has only one presently approved fish vaccine.

Meanwhile, the vaccine industry is busy trying to develop live virus and live bacteria vaccines, which are typically administered orally, for fish species. The U.S. Department of Agriculture’s (USDA) Agricultural Research Service reported back in 2004 that a patent application for a live bacteria-based immersion vaccine against Flavobacterium columnare had been filed, with more on the way.

Vaccines for salt-water fish are also in development, according to the Indonesian law firm Kusnandar & Co. According to the group, Indonesia’s Director General of Fish Nursery has stated that vaccination of salt water fish “is necessary,” and that it “will be exercised soon.”


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