Listed as an endangered species in 1966, manatees have long had an uneasy coexistence with the increasing number of commercial and recreational boats that have invaded their habitats. In Florida's waters alone, scientists from the Fish and Wildlife Conservation Commission estimate that the 3,000 manatees occupy much of the same space as the 1 million registered boats and thousands of out-of-state vacationing boats.
The consequences have been grim: in 2006, a near-record 86 manatees were killed while many more had their bones broken or skins sliced by errant propellers. Douglas Nowacek, an oceanographer from Florida State University, and a team of scientists from the Woods Hole Oceanographic Institution (WHOI) have been trying to gain a better understanding of how these gentle giants behave when boats whiz in an effort to devise better protection strategies.
Using a small, high-tech digital acoustic recording tag (D-tag), they have been recording their movements and the sounds they hear/make underwater. The device—whose main purpose is to record sound at a sampling rate of 96,000 per second—is temporarily attached to their bodies with suction cups. The D-tag is also capable of measuring the surrounding waters' temperature and to monitor the manatees' depth, roll, pitch and direction. Its design is such as to minimize any irritation on the animals' skins.
After giving the manatees a few days to acclimate to the device, Nowacek and his colleagues will begin the long process of monitoring and recording the overwhelming amount of data they expect to obtain over the course of their 2-year long study. "We will have a detailed picture. We will be able to ask questions like, what does a 20-foot boat traveling 200 meters from a manatee swimming in six feet of water sound like? This can help us determine what, if any, acoustical cues manatees do or do not react to," said Athena Rycyk, a graduate student at Florida State University who is working with Nowacek.
Via ::WHOI Oceanus: Put the D-tag on the Manatee (news magazine)