How has the dolphin population changed over the years?

The dolphin population has increased over the years due to the new advances in the animal artificial insemination field. While the above is true sonar is becoming a problem with dolphins and whales. It disorientates them and they are connecting this with beached whales in particular. I saw a very disturbing video on Japan and how they hunt Dolphins. They have a vast net set out by 3 fishing boats and then they use long slender rods which they hit so it disorientates the Dolphins and they become frantic in these nets. No matter how disoriented or frantic they are if one Dolphin is in distress then the others will come to comfort them and stay in a group which is like shooting fish in a barrel for the Japanese. There is no emotion when these so-called fishermen haul them still alive into the boats and then take them back to their fisheries. It shows them dragging and gutting Dolphins still alive and I couldn't bring myself to watch the whole video and neither could my husband. Dolphins do a lot of good for the Navy (used as tracking devices) to helping children in programs that have MS, AHD/ADD and many other diseases. The Dolphin is highly intelligent and can communicate with humans, and, in fact, are much like humans, but I would say much more loyal to their own species. Of course my husband and our friends all signed the petition against this cruelty and there is no need whatsoever to kill Dolphins. At the rate Japan is catching these Dolphins it could lower the population. Humans are the ones the misdirect the balance of nature.