TheBioacoustic Applications Laboratory(LAB) of the Polytechnic University of Catalonia (UPC), has developed a study that shows thatlow frequency sound, produced on a large scale by human activities on the high seas, causessevere damage to the auditory structures of cephalopodslike cuttlefish, squid and octopus. The result of this research is published in the latest edition of the journalFrontiers in Ecology and the Environment, of the American Ecological Society.
In the study, the LAB team of researchers, led byMichel André, exposed to87 cephalopods of four speciesdifferent (Loligo vulgaris, Sepia officinalis, Octopus vulgarisI knowIllex coindeti), a low frequency sounds, between 50 and 400 hertz. Researchersanalyzed the statocysts of the animals, that is, the balloon-shaped structures thathelp invertebrates maintain balance and position. These fluid-filled organs are similar to the vestibular apparatus of mammals and, as demonstrated in this study, are important in the perception of low-frequency sounds in cephalopods. And they found that, immediately after exposure to the low frequency of sound, they had damaged the hair cells of the statocysts, which are sensory cells of the auditory system of these animals. Over time, nerve fibers became inflamed and holes appeared. These injuries were more serious as time passed from exposure to sounds. Thus, damage to cephalopods appeared just after low-intensity exposure to low-frequency sounds andall animals exposed to sounds showed evidence of acoustic trauma.
As Michel André explains, if the short exposure to which the animals were subjected has caused severe acoustic trauma, the impact of continuous high intensity noise pollution can be considerable. In this way, if the statocyst is responsible for the balance and spatial orientation of cephalopods,sound damage to this organ will likely affect its ability to hunt, evade predators, and even reproduce. In other words, as André claims, it would not allow them to survive.
As previous studies by the research group led by Michel André show, noise pollution in the oceans has a significant impact on dolphins and whales because they use acoustic information to survive. However, this study is the first analysis to demonstrate the severe impact on invertebrates.
