It makes me sad to read these lines from your post, and it makes me wonder how in the world we still can hold up the term that we are the most intelligent being on this beautiful planet, I never heard a story about dolphins or whales or any other animal on the planet who destroys his own source of life.

I guess its time to step down from the throne and go back to school to learn what life and in special the interaction between beings on this planet and their behaviour regarding themselfs and their neighbors and the treating of the environment in which we and they are living.
Dolphins dont create plastics and they dont knew them at all before the made it to our friends, but now they are suffering from this dangerous waste in their own environment, and it seems that nobody cares about, that´s realy sad, life on earth is working for sure without man, so when we like to hold our "first place" in the intelligence on earth we should learn very fast to change a lot of things we did wrong the last (at least) hundred of years which we called the golden age of man.