"After all, if you use the special effect stones that can be picked up in this area, it seems that you can collect a large number of fish, shellfish, squid, and octopus shrimp just by waiting. These are special effects stones that a fisherman must have. special effect stones that collect sharks that eat fish, and if you place them in a place far from the fishing net, it seems that damage to the fish can be avoided, so there is a demand for this as well. Kobo seems to use these stones to increase catches and fulfill the demand for seafood in the country. There seems to be a similar dungeon in the Ochoco guild, which was at war recently. It was originally a fishing port."
I will explain by interweaving the contents written in Karne's structural diagram and the adventure stories I heard from Karne at that time.