American and French researchers determined how far in the water the sound of Pomerania antennas common spiny lobster Palinurus elephas on his head. It turned out that with a low level of background noise sounds from the largest individuals can capture 3 kilometers from the place where cancer sits. About it it is reported in Scientific Reports. So far the hearing will remotely assess the condition of populations of common crayfish: acoustic instruments, the Bank will be able to detect cancers at least on hour.
Recently gaining popularity method of passive acoustic monitoring various populations of marine animals. From afar it is possible to record the sounds that they make, and knowing what signals in what situations and with what volume generate certain types, estimate their numbers, and in some cases — and to understand, for example, whether there has come the breeding season. While most data about how it sounds and how far spread signals in vertebrates — fishes and cetaceans. About crustaceans such there is almost no information even in the case of important commercial species, one of which is the European spiny lobster.
The staff of the European Institute for marine studies (France), headed by Julien Bondalem (Julien Bonnel) from the Oceanographic Institute in woods Hole recorded using broadband hydrophones , the sounds that European lobsters make when tinder antennas hilly area of the head just below the eyes. The researchers received 1560 entries from 24 animals with the size of the carapace (chitinous plate on the head) from 2.6 to 13.5 inches.
Lobsters were first caught, were taken to the laboratory, measured and marked there and then returned to the place of fishing one of the bays of the French Brest. There are installed eight hydrophones at a distance 0,5, 1, 5, 10, 15, 20, 50 and 100 meters from the animals. Divers descended to the agreed point at the depth of 9 meters with a metal cage to the bottom, hold their breath for 20-30 seconds so that it does not create additional noise when you record sound, and get out of the cage one arthropod. The researchers took up of the European lobster, as it provokes cancers rubbing antennae the head. To ensure that the noise that is lobster in the hands of the diver, and not those who remained in the cell events were recorded on video.
N+1 · the Sounds of a spiny lobster of the species Palinurus elephas