Goldfish - a representative of the kind of karas, derived hundreds of years ago with a directional selection. This means that fish with certain signs - large pupils, short-body and leaving in the red and gold shade of scales - moved to a separate pond, where they gave offspring, thereby fastening their distinctive features. Currently goldfish is the most popular aquarium kind of fish in the world.
Sometimes people visits the thought: "It would be nice to release a poor gold fish, forced all my life to be in a close closed space, in a real river or lake. Maybe if lucky, there the fish will be able to find a house in a new place and become truly free. " This case occurred in Australia. In a local river called Vassa, biologists have become increasingly noticing the presence of atypical inhabitants for these places - goldfish. At the same time, their number over the past 15 years has grown so much so that the local research institute scored anxiety, recognizing goldfish in the river invasive view, a threatening environment and spread as a result of human activity.
Environmentalists are confident that people who released their pets in the river have become the initial reason for the appearance of fish in the reservoir of fish because of pity or inability to further contain their homes for any reason. For hundreds of years of aquarium existence, goldfish seems to have acquired a number of advantages that helped them survive in the wild and, moreover, become a dominant view of the habitat. It turned out that small goldfish in wildlife conditions are able to grow to really huge sizes: during the study of the river, the biologists came across at all aquarium specimens, weighing up to 2 kg!
But the real disugeem for the reservoir turned out to be the extraordinary voraler of goldfish, which eat almost everything that see: algae, small invertebrates, insects and even caviar of other fish. With this scenario, other fish simply does not have food, and new fry do not appear on the light that violates the ecological balance of the region.
And even the increased size of goldfish affected their ability to overcome the distance - the specialists have noticed the same part of the goldfish several times in different points of the river, the distance between which is 230 km. And in recent years, goldfish has something like seasonal migration during the reproduction period.
So far, environmentalists continue to study the behavior of goldfish in the wild and hope that they will be able to come up with a way to remove uninvited guests from the river. At the same time, direct and effective methods like networks or electrofoods here will not help - because other types of fish can suffer, which in the reservoir remained so very little.
We, depending on the example of the Australian River Vasse, we can conclude that in no case cannot be released in the wild nature of animals atypical for this locality. After all, this can lead to much more serious consequences than it seems initially, and an example with innocuous gold fish is clearly shows.