Where is the deep sea tooth in Pokemon ruby?

you have to go to the abandored ship by dewford town, find the scanner then fly to slateport and give it to the captin (forgot his name) he will trade it for deepsea tooth or deepsea scale. you can only get one of them. if you already got 1 of the the other one is impossible to get without trading or cheating. deepsea tooth evolves clampearl into huntail and the scale evolves clampearl into goryabs (sorry about spelling)