Icebreakers can separate Caspian seals, which are endangered, with offspring, the international team of zoologists reports. Researchers can not say how dangerous marine vessels are for animals, but they call for paying attention to the problem. The article was published in the journal Biological Conservation.
Caspian seals are an endemic species that inhabits the Caspian Sea. Despite the fact that the number of individuals in 2005-2012 reached 104-168 thousand, the number of species in the last century decreased by about 90 percent. In winter and early spring, Caspian seals migrate to the northern part of the sea, where they reproduce and produce offspring. Animals form large clusters on thick layers of ice, including in the Kashagan region, a large offshore oil and gas field in Kazakhstan. The path to the oil platforms at this time of year is laid by icebreakers, which, according to scientists, can threaten the Caspian seals.
The authors of the new work conducted observations from 2006 to 2013. During this time, the researchers made 39 passes on the icebreaker along the 300-kilometer route running between Bautino and the Kashagan region. For six years, zoologists counted 81 cases of passing an icebreaker when creating a new canal less than 10 meters from the cubs of the Caspian seal. In addition, already laid canals, as a rule, were colonized by seals, and pregnant females and mothers with offspring were often close to the edge. Thus, the researchers additionally recorded 281 cases of approaching the ice flow by less than 10 meters to the squirrels .
When the ship floated nearby, mothers with cubs tried to leave him, leaving the zone where the other females with the offspring were located. In some cases, the mother left the squirrel on the ice alone or in the distance. Newborn Caspian seals do not dive into water until they grow up, as their wool does not yet provide sufficient protection against cold water. Scientists have noticed about 6 cases, when the baby got wet when the icebreaker passed. “This can lead to large energy losses, and in the worst case even death of the belka,” one of the authors of the work comments . After the researchers saw the dead young Caspian seal near the canals, however what caused their death – the influence of man or other animals – is not known.The icebreaker seized the seals 20 times, while in 13 cases the collision occurred with the squirrel. Speed of the vessel in 12 cases exceeded 4 knots (7.4 kilometers per hour), and most collisions occurred at night, when nothing is visible. To avoid collisions with seals at night, the researchers suggested using thermal sensors on the icebreakers.
Researchers emphasize that excommunication of a mother from a newborn seal can threaten its safety, and in addition, it causes stress for both mothers and offspring. Nevertheless, researchers now can not accurately assess how significant the threat posed by marine vessels is for animals. The greatest damage is probably caused by poachers, accidentally catching animals along with the fish, as well as pollution, but zoologists still call for paying attention to the problem.
Representatives of the family of these seals are the only mammals able to remember the rhythm of sounds, which allows them to accurately distinguish each other’s voices. It is also known that seals with the help of vibrissae can capture the movement of water created by floating fish – this helps them to detect prey. Experts from the United States are now investigating the seal mustache to create high-precision sensors for ships and submarines.