| 英文摘要 |
It is generally known that exotic aquatic species could destroy the local ecological system and extinct the native species, while it became invasive species, due to its top predator or competition with native species. It is important to know their invasive routes and to understand their biological characters for the case eradicating management of these species. The objective of this study is to set up a model to control invasive species, especially the sucker catfish (Pterygoplichthys multiradiatus), and to investigate its impact on endemic organisms in Taiwan river. Therefore, biological aspects of the sucker catfish, such as growth, oxygen consumption, ammonia excretion, water temperature tolerance, drought resistance, hunger effect, feeding habits, fecundity, and competition with other fish were studied. Because the junior catfish can tolerate low oxygen concentration of 0.35 mg/L at 25℃, survive droughting over 4 hours, stand against hunger more than 1 month. The adaptive capacity of this sucker catfish is extremely better than other fishes. When the food is scarce in the river, it can survive longer than other fish, especially for the bigger sized catfish. From the intestines of this fish, high proportion of organic debris and alga was found, but no small fish or shrimp. In Competing with golden carp, junior sucker catfish (6 g), was not able to compete up with it, but this is not the case in larger sucker catfish (16 g). Furthermore, sucker catfish can tolerate high concentration of many chemicals, except for Niclosamide, a chemical can be used as selective toxicant. It is thought the population of the sucker catfish will expand and invade into the upstream section in Taiwan river, with an impact on the endemic fish species of periphyton and bottom feeder fish.
The present studies also collected some elimination methods of invasive aquatic species in the world for reference, including the aquatic plant (Eichhornia crassipes), African giant snail (Achatina filica), Apple snail (Pomacea canaliculata), Black striped mussel (Mytilopsis sallei), Zebra mussel(Dreissena polymorpha), American crayfish (Procambarus clarkii), Sea lamprey (Petromyzon marinus), Ruff (Gymnocephalus cernuus), and North snakehead (Channa argus). This study offers and suggests different reasonable methods for eliminating the sucker catfish and restocking the native species to maintain its original ecosystem. Finally, the mode for eradication of invasive species which needs more cooperation efforts from different parties such as fish importer, fish farmer, public, institution, news medium, is sophisticatedly set up. |