well, not a good read. the scientific basis is rather obscure. the story tells about dolphins and humans. there dolphins are intellectual. Humans want to protect them from killer whales, dolphins' natural foes. but then we face the fact that all in nature must be in harmony.
That means you for example, must not kill all wolves only to protect rabbits. Because we then interfere with nature which can cause overwhelming propagation of rabbits that can harm both to us and nature. BUT dolphins are not stupid rabbits. they can think just like humans. the morale is that all thinking creatures must be shielded.