think of ecosystem of sea

I  thought about ecosystem of sea. People want to eating food not only meat but also seafood. Because of nutrient like DHA, Omega 3, etc. Therefore, collapse of ecosystem of sea is inevitable. How can we stop collapse of ecosystem?? We must make some solution of collapse of ecosystem. For example, We may invigorate to decrease of unecessary fishing seem waste, not catching young fish ,and not use way of  unethical. But that is not easy. Why? I think most of fisher are use inethical method. It causes high profit. and most people are not educated about method of fishing. Therefore, government may educate fisher. and restricted to ethical method of fishing. As a result, I think reduce of unethical method like that.