It's important to note that this method of slaughter is also considered more humane, and for the same reason why the fish tastes better when prepared this way. Because the fish's body is not flooded with stress chemicals like it is when the brain is not destroyed first and its blood remains inside.
In other words the usual fish slaughter method leaves the fish alive as it slowly suffocates to death and then is killed. This results in muscles filled with lactic acid and other bad things.
>body is not flooded with stress chemicals like it is when the brain is not destroyed first and its blood remains inside.
I've heard both sides of this but have never actually seen any evidence. Some cultures, portions of China for example, believe the opposite - the more stressful death leads to more delicious meat.
I'm for the least stressful death for ethical reasons, but I'd be curious if there's any resources you've found that demonstrate for example your lactic acid point?
Both arguments seem quite hokey and not really rooted in science.
When muscle gets cut off from it's blood supply, it produces lactic acid through anaerobic respiration. That's regardless if the nervous system is sending out "stress signals".
It's pretty hard to kill an animal and not produce stress (the physiological kind) response in it's tissue.
The nervous system is also more than just the brain. For example your spinal cord can receive and send signals to your limbs that don't even pass through the brain.
Other commenters have posted good links, but in very large fish such as tuna, you can see macroscopic effects of this muscle degradation.[1] It's not so much an effect of the "stress hormones" in the body as just the fish overexerting itself as it flounders about in the boat, while also asphyxiating. And you're right about the spinal cord still being able to send signals to the body without the brain, which is why the full procedure is not only to destroy the brain but also the spinal cord, by inserting a rod or monofilament down the length of the spine.
> Compared to red meat and poultry, fish muscle is delicate. It needs all the structure it can get. So unlike red meat, where we like a little protein breakdown to enhance tenderness, anything that breaks down the structure of fish muscle is bad. Stress causes fish muscle tissue to break down.
In other words the usual fish slaughter method leaves the fish alive as it slowly suffocates to death and then is killed. This results in muscles filled with lactic acid and other bad things.