Mount a basilosaurus, grab yourself a turtle, have the turtle follow you on lowest setting, while you're on the basilosaurus. Move very close to the tuso it will grab the turtle ignoring the basilosaurus completely. Wait for the tuso to hold on to the turtle and then dismount your basilosaurus and quickly swim up to the tuso's face up close and feed the tusa black pearls. Very easy tame! Enjoy your sea creature!