    Séntence 1: How was. the’ population of  mnemitpsis in The black Sea and the Sea  of Azov brought under control?    Sentence 2: On'the other iand;‘in ‘the late  1980s. the. Western Aflantic ‘ctenophore  Mnemiopsis:‘leidyi -. was - . accidentally  introduced into the Black Sea anid Sea of  Azov via the ballast.tanks of ships, and has  been. blamed for causing Sharp drops in  fish Catches. by eating both fish larvae anc  ‘small Crustaceans ‘that would: otherwise:  feéd-the adult fish,