When giant squid turned up dead off Spain about ten years ago, scientists suspected their cause of death to be due to powerful sound pulses from ships. A new study shows that this might, indeed, be the case. According to Barcelona’s Technical University of Catalonia, low-frequency sounds from human activities can affect squid and other cephalopods alike.
The findings show that noise pollution in the ocean is a matter that should not be taken lightly.
“We know that noise pollution in the oceans has a significant impact on dolphins and whales, which use natural sonar to navigate and hunt, but this is the first study indicating a severe impact on invertebrates, an extended group of marine species that are not known to rely on sound for living,” study leader Michael Andre stated.
About a decade ago the remains of giant squid were found off Spain’s Asturias province not long after ships had used air guns to conduct low-frequency sound-pulse exercises in the region. Affects on the squid included reduced mantles, bruised muscles, and lesions throughout their bodies. These organs, which are located behind the squids’ eyes, help it to maintain balance and position.
In the early 2000s, however, marine biologists were unable to prove that these frequencies were causing harm to the squid and surrounding marine life. Now, though, the evidence is in.
“With this study, we now have proof,” said marine specialist Angel .
The researchers conducted the study by examining the effects of low-frequency sound exposure in 87 individual cephalopods of four different species. After two hours of constant exposure to various intensities of sound waves, the animals showed signs of damage to their statocyst tissue.
“This is a typical process found in land mammals and birds after acute noise exposure: a massive acoustic trauma followed by peripheral damage, making the lesions worse over time,” continued Andre.
The giant squid from the shores of Spain may or may not have suffered the direct impact of the sound waves, however, in either case their statocysts were practically destroyed causing the squid to become disoriented.
“The disoriented animals might wander up from the depths to the surface, where the temperature difference kills them,” explained Guerra.
Although the new research points out overwhelming evidence towards the leading cause of death for these giant squid, more research is necessary before a solid case can be made that human-made noise pollution is causing significant damage to marine life.
Photo Credit: http://oceanexplorer.noaa.gov/explorations/07philippines/logs/oct13/media/squid_600.html