Monday, 16 January 2012
Endangered dolphins surfaced in Vietnam
In the scientific world sensation. To the great delight environmentalists in the Mekong Delta in Vietnam biologists found 20 individuals iravadiyskih dolphins. Nobody knows exactly how much now remains of these rare aquatic mammals. According to the World Wildlife Fund as of August 2011, they were there not more than 87 individuals.
Unlike many other members of the family Delphinidae, iravadiysky dolphin ( Orcaella brevirostris ) is under threat of extinction. Found in one place at once 20 animals - this is an incomparable fortune, when these creatures all over the world there are only just a couple of hundred.
Iravadiyskih population of dolphins found during an expedition in a conservation area Kenzyang (Kiên Giang), located in the south of Vietnam, the Vietnamese staff of the Institute of Tropical Biology. "The number of dolphins was larger than previously encountered in the Gulf in the Philippines Malampayya or in any other place in the Mekong River", - reported on the website PC-Games , referring to one of the participants.
In general, iravadiyskity dolphin - being very interesting. It was long thought that this is the only member of the family, which is absolutely devoid of even the least some semblance of "beak" (remember that the beak of dolphins is called a ledge on the face formed by the elongated jaws). In addition, these dolphins - one of the few whales that have neck can move in different directions (the majority of this group is completely immobile).
Despite the fact that, apparently, contacts with people iravadiyskih dolphins began when the latter have only just begun to settle in Southeast Asia, is still known about them is very small. All databases zoologists they appear as "kind, where the data is not enough." We know that these are friendly and the contact animals live in groups of three to six animals.
It is interesting that the adults can move from one group to another (for the majority of dolphins is not typical, to strangers in the groups are wary.) During the study area Dolphins raise their heads out of the water and rotate to see all that surrounds them. They swim slowly, and when breathing is never stick their head completely. That is why they are not so easy to see in the wild.
It is known that iravadiyskie Dolphins can live as in the marine and fresh water. However, some populations almost never go far out to sea, and the inhabitants of the Mekong are exactly similar to the "river" form. At the same time iravadiyskie dolphins living near the coast of Indonesia, almost never go into the river. Based on these data, biologists divide the form into two subspecies - marine and freshwater.
The fishermen of Southeast Asia are very fond of iravadiyskogo dolphin because it helps them to drive the fish into the network. Moreover, observed that these animals are quickly remember where they put people and begin to consciously drive the school of fish right into the trap of knowing for sure that the network will stop him. Two centuries ago almost every fishing village on the Indonesian archipelago had its own "local" school of dolphins that have always chased the fish directly to their networks. It's funny that people of different villages sometimes even sued their neighbors, so if you could lure a flock in their area of fishing (although, in fairness, had to plead with the dolphins).
However, it is a network fishing and ruined in the end, this abundant species. The fact that fish in pens in the network has been involved the whole school, including babies and teenagers. They, unlike adults, are not always able to stop in time, so often entangled in nets and killed. As of mid-twentieth century, infant mortality in many populations iravadiyskogo dolphin reached 60 percent (which apparently led to a drastic decrease in the population). A transition to the inhabitants of this region trawling turned to dolphins catastrophe - the infant mortality rate in some places rose to 80 percent!
May also have played a fateful role and pollution of the marine and river water runoff from fields that contain toxic to many animals, fertilizer, which is intensified by the end of the last century. For example, in some samples of tissues of dead animals found high concentrations of mercury, which is probably of the gold mines, located upstream of the river. As for poaching, then it probably does not affect the decline of this species, as in most countries of the region iravadiysky dolphin is considered a sacred animal and the locals do not touch it. (A careless tourists, heads to hunt for them, a great risk - for them it may drown.)
Thus, since the main problem for iravadiyskih dolphins have long been creating fishing and water pollution, by the initiative of the International Union for Conservation of Nature (IUCN), they were listed as endangered as a species threatened with total destruction. According to the latest report of the World Wildlife Fund, the Mekong is found no more than 85 species of dolphins iravadiyskih. In total there are about 200 individuals, although at the beginning of the century was over five hundred. True, perhaps, the number of dolphin iravadiyskogo by 2005 had fallen more and wine ... zoologists!
Not long ago, Australian scientists have realized that dwells off the coast of the continent's animal Green, previously thought iravadiyskim dolphin, it is not. In 2005, after conducting various studies, including molecular, it was found that animals that make up the Australian population, in fact, belong to another species, which was named Australian snub-nosed dolphin ( Orcaella heinsohn I ). The external differences between the two species are minimal - Orcaella heinsohn I iravadiyskogo different only in that it includes the body color or two, but three colors.
However, as a result of this discovery dolphin population iravadiyskogo immediately reduced to about 230 individuals (the exact number of Australian snub-nosed dolphins, too, no one knows). Now belonging to this type are only those populations that live north of Indonesia. Until this discovery it was thought that around Indonesia for a total of approximately 100 animals inhabit in the mouth of the Irrawaddy River in Burma - 20, and the Mekong - somewhere 85-87. Now the Mekong population "increased" by 20 individuals. However, this still does not inspire much optimism for biologists.
"The number of dolphins continues to decline further, few cubs reach the age of reproductive capacity" - warns adviser of the World Wildlife Fund's Mekong region by Stefan Ziegler (Stefan Ziegler). The World Wildlife Fund called on the Government of Cambodia, so that it has determined the legal framework for the protection of endangered species. "In conservation areas should be banned trawling" - says the biologist.
According to the World Wildlife Fund in Laos, despite operating in this country have legislation to protect animals, the number of dolphins iravadiyskih also declining and currently there are no more than eight individuals. Most of the population size of these aquatic mammals seen on the border between Cambodia and Laos. Now it is safe to say that these dolphins live in Vietnam (although until now it was believed that there are animals disappeared in the second half of the twentieth century).
Let's hope that the governments in whose territory proceeds Mekong, will take all measures to protect this friendly and useful for fishermen dolphin from extinction. Because otherwise suffer not only the ecosystems in which it resides cetaceans, but also fishermen. No one else will drive them to the fish directly into the network ...