A troubling new study has put hard numbers on something many people have long suspected: fish pulled from water can endure long stretches of severe pain before they die. Researchers found that rainbow trout, one of the world’s most farmed fish, can suffer for as long as 22 minutes when killed by traditional methods like air or ice asphyxiation. This is one of the most common ways to slaughter fish because it’s cheap and easy, but it comes at a huge cost to the animals. The team used a new tool called the Welfare Footprint Framework (WFF), which combines data on the intensity of pain and the length of time it lasts to estimate the animal’s overall suffering. They pored over dozens of studies to piece together what happens to fish after they’re removed from water. Just five seconds in air triggers a stress response similar to panic in humans, with the fish frantically twisting and turning. As their gills collapse, carbon dioxide builds up in their bodies, setting off the body’s pain alarms. It can take anywhere from 2 to 25 minutes for them to finally lose consciousness. The researchers calculated that on average, each kilogram of fish killed this way racks up about 24 minutes of moderate to extreme pain, with some methods causing over an hour of agony. More humane alternatives like electrical stunning could drastically cut this suffering, potentially saving up to 20 hours of severe pain per dollar invested in better equipment. But current stunning systems aren’t always reliable, and extra stress before slaughter can undermine their benefits. Research Paper 📄 PMID: 40473790 PMCID: PMC12141439