Complex sentence: It has been suggested that methoprene is responsible for killing and stunting the growth of lobsters in Narragansett Bay; the real life relevance of this is doubtful given that methoprene is not used in the open ocean or near beaches.
Split into simpler sentences: It has been suggested that methoprene is responsible for killing and stunting the growth of lobsters in Narragansett Bay. The real life relevance of this is questioned by some, because methoprene is not used in the open ocean or near beaches.