and blames the pollution of the seas. richelle carey reports. >> oceans have lost 50% of the vertebrate populations, in other words half the fish mammals birds and reptiles that depend on the oceans are gone. some fish species have declined by almost 75%. for this report, the organization tracked thousands of marine animal populations around the globe since 1970. it says the decline is more serious than previously thought. not only are the vertebrates disappearing but their habitats are being destroyed and degraded. the report shows half the world's coral reefs and half of all sea grasses have been destroyed. over 25% of all marine species live in coral reefs. yet they cover less than .1% of the ocean. >> now we can see in the distance there, the industrial development and the destruction of the world heritage listed --