The presence and the alive obstinacy of the species of the survival or the disappearance are a matter of the adaptation to the characteristics of the ocean and the genetics of the type of the same factors, then any alive body is characterized by a space biogeographical presence, he can adapt somewhere else and adapts, but according to physiological flexible, and the extinction of a category presents factors, including the energy genocide in Cairo or in genetic processing of the private life, if the diversity and the intensity of the impact do not allocate the natural ecosystem and the sales, only the frequencies of balance.
I would have to totally agree with the point Artur raised. I would like also to add the fact that we do have instances of such phenomenon in many heavily industrialized European countries (and consider that this is ONLY happened in a matter of a few tens of years). That's why we have restoration plans devised.