A new study published in the journal Nature by an international team of scientists shows that baleen whales use a special form of larynx as opposed to toothed whales that use a nasal organ to produce sound. Complex whale melodies were first recorded fifty years ago. Scientists think that the "songs" are a form of communication between individuals. The study of minke, sei and humpback whales found a novel adaptation that allows these toothless filter feeders to produce sound underwater while holding their breath.
Unfortunately for whales the sounds they produce are in the same frequency range as ships--up to 300 Hz and a depth of 100 meters. Whales cannot outcompete the noise occurring from shipping by diving deeper or singing louder. Consequently noise alters their behavior often requiring more exertion, which threatens their long term survival. Noise at mating sites may disrupt reproduction. Conservationists are concerned that the rush to exploit the sea bed for rare minerals will have a devastating effect on a wide range of marine creatures not just large marine mammals. More research needs to be done on the effects of noise in the ocean so effective regulations can be promulgated.
[whales feeding; credit Stanford U.]
