From Discovery News:
Thousands of Humboldt squid died off the coast of Oregon in 2004 and hundreds again in 2008. The culprit was originally considered a shift in deep-sea currents, but a new study pinpoints the physical trauma noise pollution can inflict on cephalopods and raises new concerns over the incidents of squid strandings. Dolphins and whales and other marine mammals aren’t the only sea life vulnerable to noise pollution from human activities.
Earlier indications that squid might be susceptible to noise occurred in 2001 and again in 2003, when giant squid washed up along the shore of Asturias, Spain. After struggling to identify the reason, biologists eventually concluded that the deaths were most likely related to the presence of vessels using seismic air guns for geophysical prospecting of the seabed.
A new study, published in the journal Frontiers in Ecology and the Environment, has found that even low intensity noise can leave cephalopods damaged and likely to wash ashore. In the study, led by Michel André of the Technical University of Catalonia in Barcelona, biologists exposed 87 individual cephalopods of four species— Loligo vulgaris, Sepia officinalis, Octopus vulgaris and Illex coindeti—to short sweeps of relatively low intensity, low frequency sound between 50 and 400 Hertz (Hz). Then they examined the animals’ statocysts – fluid-filled, balloon-like structures that help these invertebrates maintain balance and position in the water. André and his colleagues found that, immediately following exposure to low frequency sound, the cephalopods showed hair cell damage within the statocysts. Over time, nerve fibers became swollen and, eventually, large holes appeared…
Read more here.