First of all, although sashimi is eaten raw and delicious, it needs to be treated. First of all, there are requirements for the species of fish used as sashimi. You can't just grab a deep-sea fish and eat it. Many fish contain a lot of bacteria and parasites in their bodies, which will make the digestive system of adults uncomfortable if eaten raw. Moreover, people who catch fish often know that they don't eat fish raw, but cook them. High temperature will kill parasites in those fish and won't harm people's health. After fish that can be used for themselves, such as tuna, are fished up at the bottom of the sea. Part of it can be used for sashimi, but the other part, the other part can only be used for other purposes.
For those fish that are suitable for sashimi, when fishing in the deep sea, you should know that the sashimi is to cut the fish into very thin pieces with a knife, so it is very troublesome to fish in the deep sea, because you have to deal with the internal organs of the fish and clean them. Moreover, people who fish in the deep sea are generally fishermen. They salvage those fish and have no mind to sashimi them. Even if they eat them, they will cook them to supplement more calories and absorb them better. But thinking about how to salvage more fish and how to transport them back to a safe harbor before the storm comes.
Therefore, we seldom eat fish that have just been fished out in the deep sea. After all, we already have a very mature human culture, and eating sashimi raw is only one of many eating habits.