Mystery Dive Explained

Now that you have all had a chance to watch the video and take a stab at the questions, its time to give a little more info on that dive. The dive took place at an offshore aquaculture cage were we are monitoring the movement patterns of sharks. To accomplish this, acoustic tags are implanted into the sharks which continuously send out a 'ping'. Remote receivers are used to listen for 'pings' when a shark is in the vicinity of the receiver. The receivers need to be downloaded periodically to find out what sharks were detected and when. This dive was one such mission, where we retrieved the receiver and replaced it with another. This receiver is part of a 'listening network' of receivers located throughout the Hawaiian Island chain, which we use to track sharks and other fishes throughout the archipelago. This image shows the location of our receivers.

Tiger sharks initially tagged at French Frigate Shoals atoll have been detected as far away as the island of Hawaii! This is the only shark species that has been detected regularly moving between atolls and islands. With this technology, we are able to better understand the behavioral ecology of these top predators. This information will increase our ability to properly manage resources within the Papahanaumokuakea Marine National Monument.