As the National Oceanic Atmospheric Administration conducts an investigation into whether the military's recent use of sonar could have been the cause behind the beaching of three whales in Southern Guam, we take a closer look at the effect sonar has on marine mammals.

Professor Peter Houk is an ecologist at the University of Guam's Marine Lab. He says marine mammals like the beak whales that were stranded in Merizo last week use echolocation, which is their form of sonar. Houk adds marine mammals use echo location to locate prey, predators and mates, explaining, "So when, say, military sonar or something like that depending on the frequency, I think they stated mid range frequencies are the worst depending on the frequency the sonar calls that the marine mammals are making can be disrupted."

Three beaked whales were stranded in Merizo last week, with the help of local residents two were able to make it back out in the ocean, while one died. Officials are currently waiting for the results of a necropsy of the dead whale which was conducted in Hawaii last week to determine its exact cause of death. The military confirmed with KUAM News last Friday that they had, in fact, use sonar during a training exercise conducted the same day and around the same time the whales washed ashore.

According to Houk the use of sonar drowns out the noises that marine mammals rely on for their survival altering their response to prey, predators or mates. It can also cause whales to change their dive patterns in a way their bodies cannot handle resulting in dire consequences. He added, "In the past they think there is a study out there they believe they have linked that to a beaching event or stranding event although direct cause and effect is very hard to do science is based on probabilities probability that something happened and then this happened after.

"I think the most severe things when you think of what they use sonar for finding out when and where predators are finding their foraging so getting their food so these are some of the basic functions of life needed so depending on how frequent sonar was there and what its impact was is it just something that has a short-term impact or a long-term impact getting the answers to those questions are obviously key."

According to the National Resource Defense Council website many beached whales have suffered physical trauma including bleeding around the brain, ears and other tissues as a result of sonar testing. Department of Agriculture biologist Brent Tibbat told KUAM that although he is not an expert in his initial assessment of the whale, it did not appear that it had any health issues however official results are pending.