When we sit at the table in front of a fish fillet, we don’t usually think about the life or death of the fish. Is the romantic idea of a fisherman who throws a net and picks up a happy fish that dies right away on the ship, is it consistent with reality? More than half of the fish we consume is farmed: how do they die in the fish farms?
Many consumers do not know that, while extractive fishing continues to suffocate fish on ships, fish farmers and scientists have been working for years to improve the stunning and slaughter process of animals raised through aquaculture.
Most of the farmed fish we consume take between one and two years to reach their commercial size, which ranges from 250 to 500 grams. This is not much if we compare it with the weight of other small animals such as chicken (2-4 kg) and rabbit (2 kg).
Here is a logistical problem. Fish weigh little, so you have to grow many more to produce a ton compared to chickens, if not a cow. There are many more animals to handle and, therefore, to sacrifice.
Dorada and sea bass are grown in the Mediterranean Sea in circular nurseries near the coast, which can hold between 20 and 60 tons of fish. That is many living beings. As they grow, the nursery is cleared, by gradually extracting 3 or 4 tons with a net. Each punch is deposited in a tank that contains half water and half ice. There the fish cool down and die.
This procedure is called stun or sacrifice for hypothermia and is accepted by the World Organization for Animal Health as a valid method. As you can imagine, a fish may not find it very funny to move from water at 25 ° C to 1 ° C in a matter of seconds, and usually tries to escape. On the other hand, can you imagine how a fish thinks? How do you feel pain? Are you aware that you will die?
Stun in less than a second
Scientists have been discussing the fish perception of pain for many years and animal consciousness in general. In this debate, there are two main sides. Some argue that fish do not have the necessary equipment to feel pain like mammals. Others recognize that current science does not know how to quantify the perception of pain, even in humans, so we must follow the precautionary principle, accept that all vertebrates can feel pain and try to minimize it.
This debate has encouraged a series of research projects to find out if fish feel pain or not and what is the best way to sacrifice them. At the same time, laws have been passed in Europe to protect animals, with an eye on the methods of sacrifice. Regulation 1099 of 2009 states that it is necessary to stun animals before slaughter (and make sure they are unconscious before bled). This stunning should occur in less than a second.
This time limit is a problem when we talk about fish. Breeding methods have been developed to minimize stress; stunning methods, maintain product quality and kill many animals at once because they are many and very small.
In addition, they must be captured, removed from the water and cooled as soon as possible, since their useful life is short. Thus begins the race to see who invents an ideal stunner for fish, faster than stunning for hypothermia, in which it is estimated that fish take between 5 and 20 minutes to die.
Five ways to die
In recent years, and according to the most important database on scientific studies in the world ( Web of Knowledge ), 18 studies have been published that measure the welfare of fish according to different stunning methods.
These methods can be grouped into five categories:
- Electrical stunning (which can be in or out of the water),
- percussion (as it sounds, give the animal a blow to the head with a blunt object),
- for hypothermia (ice),
- with gases (such as CO₂, dissolved in water),
- and the iki jime or spiking (pierce the brain with a sharp object).
Anesthetics have also been tried, but it is thought that they can end up in the meat and reach the consumer, so they have been banned in Europe.
On an industrial level, salmon is stunned by percussion, trout by electric shock and most gilthead sea bass and sea bass by hypothermia. On a commercial level, it seems that electrical stunning is going to be the standard and there are already several prototypes working.
What’s new is a stunner that pumps fish from their ponds and emits chain discharges, without having to take the fish out of the water. The advantage is that it stuns animals quickly and they reach the ice unconscious. But they are not in common use yet since they require significant investment and the level of discharge must be adjusted according to the conductivity of the water and the size of the fish, which is not always easy.
In addition, there is some concern about the occupational safety of operators who have to apply water discharges in conditions that are not always favorable, for example onboard a ship. However, we will surely see more similar stunners in our fish farms in the near future. All to get the fish to reach our plate in a more ethical way.