The I-Kiribati had daggers made out of stingray spines, but that wasn't quite heavy non-metal enough, so their preferred weapons were gigantic wooden swords lined with razor-sharp shark's teeth. And even those apparently weren't quite enough like concept art for Waterworld 2: This Time It's Person-Gill. So they came up with the taumangaria, a three-pronged trident lined with tiger shark teeth. There is not a single photo of the taumangaria that isn't borderline nightmarish, and with good reason (a classic move was to try to slice open the artery inside your opponent's elbow).
All of these weapons were used in epic duels, which could last so long that each fighter was advised to bring a friend to prop him up if he started passing out from heat exhaustion (the large back shield was to protect against rocks thrown by the opposing spectators). So stop picturing Pacific history as all idyllic beaches and coconut parties and start picturing a bunch of awesome maniacs whaling on each other with shark tridents.