The main reasons why shark meat is so unpalatable and smells like urine are as follows:

First: Shark’s urinary system is very special.

In fact, most animals have a very complete urinary system, but sharks are different. The shark's excretory system and its reproductive system are all concentrated together, which is the cloaca. Sharks use this organ to ovulate, and daily excretion is also carried out through this organ. However, the capacity of this organ is limited, so when it cannot meet the shark's excretion requirements, part of the excrement will be excreted through the shark's skin.

So the skin of sharks will excrete for a long time, and the skin will retain a lot of excrement smell. This smell has experienced a long period of edification and is difficult to remove, so the smell of shark meat There is always a smell of urine, which is very unpleasant.

Second: Osmosis occurs in the shark's body.

In fact, when it comes to osmosis, I believe everyone knows it very well. That is, if the concentrations of water on both sides are different, then low-concentration water will enter the high-concentration waters. This reaction also occurs in sharks. Sharks live in the deep sea, so their osmotic pressure is generally lower than that of sea water, so the water inside the shark will penetrate into the sea water.

But this situation will cause the shark's body to be short of water, so the shark needs to swallow sea water to replenish water. However, the salt content in seawater is very high. In order to maintain the stability of the body's osmotic pressure and prevent it from circulating endlessly, sharks have slowly evolved the ability to store urea in their blood. In this way, the shark will not infiltrate frequently.

In other words, sharks are soaked in their own urine every day. It takes many years for a shark to be culled by humans, which means that the shark has been soaked in urine. Having been in my own urine for many years, the smell of shark meat must be very strong, and it is not something that can be easily removed.