Canary Islands

Heavy ship traffic deafens the whales. Sea protector today see a relevant threat factor for marine mammals in anthropogenically generated noise. The relationship between underwater noise and damage to the marine mammals are acoustically oriented as well as stranding events thus related is now indisputable. Sea protector today see a relevant threat factor for marine mammals in anthropogenically generated noise. The biologist Dr. Michel Andre was one of the first evidence for noise-induced hearing loss in whales (University Las Palmas de Gran Canaria) in sound tests of sperm whales: these animals, which live in the territory of the Canary Islands, have caused hearing damage by heavy ship traffic and often collide with ships.

About 100 ships move daily between the ports of Santa Cruz, and Las Palmas. These waters are also the Habitat of many whale and dolphin species, in particular of sperm whales. Due to their size and their unusual diving behavior, they are a threat to shipping. This biggest type of toothache after trips to over 3000 meters deep and up to 90 minutes duration suddenly shows up, then almost motionless for 5 to 15 minutes on the surface to remain – one for ship crews barely visible to over 50 ton and 20-metre barrier. To warn the whale collisions, researchers searched for a signal system installed onto the ferries. So played a team led by Michel Andre about underwater speaker sperm whales with six sounds and registered the reactions. It natural sounds and noises were used only natural enemies of “Moby Dick” – or ship engine noise and artificial sounds like a 10 kHz pulse as the voices of killer whales – as well as giant squid and pirate whalers.

All signals in the frequency range of hearing of sperm whales were (0.2 to 32 kHz). A total of 57 animals were from a distance of approximately 100 meters for 10 seconds with about 180 decibels (dB) volume sound. For comparison, a Jackhammer is annoying with about 100, a jet plane with 140 dB. However sound waves under water spread out quite differently than in the air, which complicates comparisons, in particular because whales and dolphins mainly acoustically and very much less visually orient themselves in contrast to the people in their environment. The sperm whale’s rhythm of life was taken into account in the experiments by Michel Andre. In each of these three cycles consecutively played off the signals. Although the acoustic raids for the animals must have been very loud, only the 10 kHz pulse triggered an escape reaction resting whales. Other signals, they did not interfere, and during the stages of swimming, they showed no reaction to the 10 kHz pulse, Michel Andre baffled noted. But the hope at least partly effective signal shattered after further attempts. They auditioned a second time the 10 kHz pulse the same animals, they ignored it. These results make believe the native of the Canary Islands whales to noise have developed by Michel Andre clearly what tolerance. The continuous noise level generated by the ship’s engines and fan blade could have meant that has lost her hearing in the low frequency range sensitivity. High speed ferries would therefore late perceived by them. His thesis is supported by the medical examination by two deadly travels over whales, which revealed that the two animals were deaf and they could not therefore hear the deadly threat. Ulrich Karlowski