Otters eat sea urchins, which eat kelp. With its major predator gone, urchin populations exploded and consumed most of the kelp. Fish and other animals associated with kelp beds disappeared. In many cultures, humans value animals for reasons other than maintaining ecosystem health. Animals play a prominent role in the religions or belief systems of many cultures.
Many people value other species for the enjoyment they give.
Still others believe humans have a moral obligation to live in harmony with other life forms. Whatever their reasons, most people agree that it is important to try to prevent species extinction. Not all people agree on how to do this, however, or what to do when human needs conflict with needs of other species. It is only recently that people have begun to be concerned about the decline of wildlife that has no commercial value to humans. Wildlife laws originally were passed to control exploitation of animals that people hunted.