Do Brine Shrimp Feel Pain When Frozen?
Freezing brine shrimp is a common practice for fishkeepers who breed these tiny crustaceans as live food for their fish. But it raises an ethical question – do brine shrimp feel pain when they are frozen? As caring fishkeepers it is important that we consider the welfare of any living creature in our care. In this article we’ll examine the evidence on both sides of this issue.
First let’s look at the basics of brine shrimp biology. Brine shrimp, also called sea monkeys or artemia are small aquatic crustaceans that live in salty lakes and marine environments. They have a short lifespan of just a few weeks to months. Brine shrimp swim by moving their many pairs of legs, and they feed by filtering microorganisms and organic particles from the water. Their bodies are relatively simple, with a digestive system, reproductive organs, a gas-filled swim bladder, and a nervous system.
The brine shrimp nervous system is decentralized with neural clusters or ganglia rather than a brain. This simpler nervous system may limit their capacity to process and feel pain. On the other hand recent research shows that even simple nervous systems have more capabilities than previously thought. For instance biologist Robert Elwood has demonstrated that prawns show negative responses to dangerous or painful stimuli that go beyond basic reflexes. So the jury is still out on whether brine shrimp can feel pain or not.
Now let’s consider what happens when brine shrimp are frozen. Fishkeepers will often hatch brine shrimp eggs then freeze batches of the live baby brine shrimp for later feedings. When brine shrimp are frozen, ice crystals form in their bodies as their liquid water converts to solid ice. This ice crystal formation can rupture cell membranes and damage organs. We know that in humans and other animals, tissue damage causes pain signals to be sent to the brain. So if brine shrimp experience pain, suddenly having ice crystals form throughout their bodies would very likely cause that sensation.
On the other side of the debate, some argue that brine shrimp brains are too simple to process pain, and that freezing happens so rapidly that their nervous systems wouldn’t have time to react anyway. However, research on lobsters and other crustaceans shows that they continue to display signs of awareness and responsiveness after being frozen. This suggests that freezing may not disrupt all neural activity immediately.
Ultimately there is no definitive scientific answer yet on whether brine shrimp feel pain when frozen. But as fishkeepers who care about all creatures in our tanks, it makes sense to err on the side of caution. Here are some tips on freezing brine shrimp in a more humane manner:
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Use rapid freezing methods. Flash freezing brine shrimp in liquid nitrogen or a deep freezer will freeze their bodies faster, giving less time for pain sensation if it does exist.
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Anesthetize them first. Soaking brine shrimp in clove oil or another fish-safe anesthetic could potentially relax their bodies and nervous systems prior to freezing.
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Freeze eggs instead. Brine shrimp eggs remain dormant and dehydrated when stored properly, so freezing eggs eliminates any doubt about pain. Simply hatch smaller batches of eggs as needed.
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Consider alternatives. Some fishkeepers culture and feed live paramecium, daphnia, or other small organisms that may raise fewer ethical concerns.
Brine shrimp are fascinating creatures that serve an important role in many fish and aquatic invertebrate diets. As we learn more about neurobiology and the capabilities of simple nervous systems, we should remain open to revising our ethical considerations when it comes to all living things. Freezing brine shrimp humanely demonstrates thoughtfulness and compassion for even some of the tiniest lives in our care as fishkeepers. What are your thoughts on this issue? I’d love to hear other perspectives on how we can show kindness to the living creatures that enrich our tanks and lives. Please leave a comment below!
Practicing mutilation in reproduction
The majority of prawns consumed in the UK come from farms from South-East Asia. On all of these farms, the “breeding stock” are mutilated to change the time of year when they can mate. Females are forced into an unnatural reproduction cycle as a result.
Prawns have a reproductive gland in their eyes which tells them when it’s the right season to mate. For prawn farmers, they want prawns to breed all year round. To hurt the prawns’ eyes, they cut them open with razor blades, tie off the eyestalk with a tight thread, use a red-hot wire, or pinch the eyestalk. Because these methods damage the gland that controls reproduction in female prawns, they have to breed over and over again.
When prawns are mutilated in this horrible way, they constantly rub the hurt area, they get lost, and they flick their tails over and over as a way to get away. All three actions are consistent with behaviours in other animals that occur when their pain receptors are activated. The cruel process of cutting off the animals’ eyestalks leaves them blind and stranded in dirty, crowded water, where they are used as a breeding machine.
Do prawns have a central nervous system?
“But prawns don’t have central nervous systems,” you may say in response. “So they can’t feel pain, really. ” It is true that prawns don’t have central nervous systems. But Professor Robert Elwood, who has spent decades studying the fascinating lives of crustaceans, doesn’t agree with the idea that having a central nervous system is the only way to show that you can feel pain. He says that telling an animal it can’t feel pain because it doesn’t have the same biology as humans is like telling them they can’t see because it doesn’t have a visual cortex.
He’s absolutely right – we can at the very least all agree that prawns have vision. It doesn’t mean they can’t see just because their species evolved to see with a different system than humans, who have a visual cortex. In the same way, an animal can feel pain in more ways than one besides having a neuronal system.
This is understood by the European Food Safety Authority, an independent body that bases its conclusions on scientific research. For over 15 years, the EFSA has been calling for prawns and shrimp to be placed in the same category as animals such as chickens, pigs and sheep, who are understood to feel pain.
Feeding FROZEN BRINE SHRIMP to my fish
What happens if a shrimp is frozen in a brine?
This phenomenon spreads until there is lack of water or salt to form a new eutectic. Brine freezing of shrimp involves two steps. The first one is to decrease the temperature of shrimp from positive to a range of minus-8 to minus-12 degrees-C with the brine.
What are the side effects of eating shrimp?
Shrimp allergy can be identified from signs and symptoms that appear after consuming shrimp or smelling it, such as itching, the appearance of red plaques on the skin, swelling in the face, especially in the eyes and mouth, and in the throat creating the feeling of a lump in the throat.
What is brine freezing of cultured shrimp?
Brine freezing of cultured shrimp is a processing technique that preserves product quality and texture. Photo by Darryl Jory.
How do you freeze shrimp in a brine?
Brine freezing of shrimp involves two steps. The first one is to decrease the temperature of shrimp from positive to a range of minus-8 to minus-12 degrees-C with the brine. The second step involves reaching the deep-freezing temperature of -18 degrees-C in an air blast tunnel.