Goldfish (Carassius auratus), favored by hobbyists are raises and grow in size 10 times smaller domestic fish getting into the natural lakes and rivers. This conclusion was made by Australian scientists in a paper published in the journal Ecology of Freshwater Fish.
Employees of the University of Murdoch and James Cook observed the population of aquarium goldfish during the year issued by the owners in the West Australian River Vasse . To observe them using a passive acoustic telemetry installing scanners at the various sections of river hydraulics
It turned out that in the river there is a stable population of goldfish -. On average, each individual enters the field of view of 64 percent of the scanners days a year. At the same time representatives of the invasive species is very mobile: on the day they moved in an average of 300 meters of the riverbed. One of the fish registered for the year overcame a distance of over 230 kilometers, including 5.4 kilometers in one day
Also, scientists have recorded significant seasonal migration goldfish:. During the spawning season they prefer to move into water reservoirs stagnant water connected to the river channels. According to researchers, these ducts can be a convenient place for mass fish catches to control their population
In the food-rich waters of the Vasse goldfish in about 20 years living up to impressive sizes. Many of captured specimens have weighed more than a kilogram, and the largest weighed 1.9 kilograms. According to researcher Stephen Beatty (Stephen Beatty), a similar rate of growth was not observed anywhere in the world.
Beatty said that in the wild goldfish are omnivores and cause significant damage to native species, destroying the food supply, eating caviar other fish and spreading infection. In addition, they raise from the bottom mud and destroy algae.
In an interview with Mashable Australia Beatty asked the owners of aquarium fish is not to let them into the open waters. The best way to get rid of annoying pet he called putting it back in the pet shop, and if this is not possible -. Euthanasia in the freezer
Goldfish domesticated by man in the VII century BC (they were taken from the carp) and They are now among the most popular aquarium fish. Their stable populations descended from outstanding individuals of the owners, there are many freshwater ponds in warm climates, where they are also harmful to native species.
Goldfish – is not the only invasive species of freshwater fish in Australia. Recently, the authorities announced plans to exterminate European carp or carp, in the Murray River with the help of highly virulent herpesvirus. Biological methods to combat invasive species were used in Australia in the past: in the 1950s, the authorities have reduced the populations of rabbits, their infecting pathogen myxomatosis. However, for 70 years the animals and pathogens have adapted to each other – at first increased resistance to infection, and the latter began to cause a milder form of the disease
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