Abstract:

The topmouth gudgeon (Pseudorasbora parva) and goldfish (Carassius auratus), two small omnivorous freshwater fishes, have been introduced into many countries by human activities during recent years. Wide and severe ecological harm has resulted from the pathogens that these fishes carried and from the extremely large populations of these fishes. Based on data from a large number of distribution points systematically identified by our long-term sampling survey and from the FishBase, and on high-resolution environmental data, we used Maxent to obtain the first prediction of the potential global distribution of the two fishes. The results of the study suggest that the topmouth gudgeon and goldfish have an extremely wide potential range in the world and that this is especially the case for the goldfish. In fact, all continents except Antarctica include many potential habitats for the two fishes. Accordingly, these two fishes may spread more widely and create more serious danger to the aquatic ecosystem in the future as human activities continue to expand. Especially, the Mississippi valley in the middle part, and the eastern and southern coasts of the United States of America, region from Seattle to Vancouver of Canada will be the areas of the topmouth gudgeon with highly potential invasive risk. And those areas for goldfish will be the countries of Argentina and Brazil in South America, Guinea and Cameroon in West Africa. Our results also suggest that the use of Maxent with comprehensive distribution data and high resolution environmental data represents a new and valid method for obtaining early warnings serving to prevent the danger of biological invasion.

Key words: Carassius auratus, Pseudorasbora parva, potential distribution area, ecological risk, Maxent, biological invasion