(Illustration by Joelle Bolt) 

The Fish Injectors

In addition to its world-famous music festival where people enjoy folk melodies while munching on wild-boar burgers, Scotland's Isle of Sky is also home to a crack crew of, let's call them, fish-medics. This isle's Aqualife Services is the world's largest fish-vaccination company—and also one of the fastest. With 50 trained employees in Scotland and Norway, Aqualife Services purports that one of its employees can vaccinate up to 25,000 fish per day. So a four-person team can vaccinate half a million fish a week. "Most of what we do in Scotland and Norway are salmon," explains technical manager Phillip Brown. "The salmon begin life in freshwater hatcheries, where they are vaccinated and then are moved to net enclosures in the sea. The risks of infectious disease are higher in the sea, as sea water is a better medium for bacteria and viruses to thrive."

Such aquatic afflictions can devastate the industry. In the past, half of farmed fish contracted infectious diseases and died before being turned into a healthy dinner. In 1980 for instance, bacterial disease almost destroyed salmon farming in Norway, and it took buckets of antibiotics to save the fish. Even worse, antibiotics don't always work, and they are very expensive. Still fish farming keeps growing. In the 1950s, fish farmers raised about one million tons of marketable fish, but in 2004, that production rose to 59.4 million tons.

Today fish farmers prefer vaccination to keep fish healthy. At first, the vaccine was simply poured in the water, and fish would literally swim in it, but that is clearly an inefficient use of the medication. In the 1990s injectable vaccines for fish became widely available. Today there are vaccines for many species—salmon, trout, carp, Atlantic cod, catfish, seabream and other varieties—to stave off infectious disease and make aquaculture a more viable business.

But still, the mind boggles with the thought of picking up fish, one by one, and giving them a shot. It takes skill to hold a sedated fish and inject the vaccine in the underbelly, being careful to miss the swim bladder and vital organs. Many fish vaccines are also delivered with an adjuvant that kick starts the fish's immune system. If the vaccinator gets stuck, though, the adjuvant can cause the loss of tissue, fingers and even dangerous allergic reactions.

That's why many fish farmers turn to the pros at Aqualife. They can poke thousands of fish efficiently. Furthermore Brown says that fish vaccinated by Aqualife have lower rates of abdominal inflammation on what is known in the fish business as the Speilberg scale.

Since 1996, the company claims to have vaccinated 466,526,551 fish, which means there is a strong possibility that one of those fish has been poached, filleted or fried and ended up on a table near you as a healthy—and disease-free—meal.