Invasion from above
Have you ever wondered how isolated waters become populated by fish? Apparently this question was bothering people for some centuries now and just recently researchers from the University of Basel conducted an experiment which concluded that birds may be responsible for bringing fish eggs to faraway locations.
The researchers offered fertilized eggs of two invasive fish species to eight mallards. Each duck was served roughly 500 eggs from each type of carp. Researchers discovered that 6 of the ducks had passed living eggs in their feces, albeit only 12 of the embryos contained in the 18 eggs that researchers were able to extract remained viable. One baby common carp and two Prussian carp hatched, while nine eggs succumbed to fungal infection.
Although the result might not seem like much, with the amount of ducks and fish out there in the wild, it seems a very plausible explanation to the puzzling question. And once again it never ceases to amaze me how life will always find its way.