>> reporter: producers followed these tusk fish for six weeks, discovering new behaviors, using coral to crack open a golf-sized clam shell with his tiny mouth. it also highlights the effects of global warming an pollution. in sarasota bay, dolphin's calves are dying. >> clearly, something else is going on. >> reporter: an estimated 8 million tons of plastic are dumps into the ocean each year. and the american scientist from the university of georgia hopes this will make people think. >> there's a native american phrase, we don't inherit the earth from our ancestors, we borrow it from our grandchildren. everybody can do little things, and those little things add up and collectively, they make a huge difference. >> our thanks to james longman. and you can see it all at bbc america on demand. i'm david muir. i hope to see you tomorrow. good live where you live. this is abc 7 news.