Invasive aquatic species pose a significant threat to all water bodies from small streams to the Great Lakes. Most invasive aquatic species dramatically alter food web structures, decreasing the food available for native species. This direct competition leads to population decline and loss of biodiversity. The loss of native fish species also dramatically impacts the fishing industry, both commercial and recreational. Aquatic invasives pose a serious threat to the use of water bodies, making it difficult and even dangerous to swim and boat. Human activity is a primary reason why invasive aquatic species spread; improper equipment cleaning and illegal transportation of fish has made it possible for the invasion of isolated water systems. All water sport equipment, clothing, and pets must be cleaned thoroughly after they come out of the water. Also, it is illegal to transport fish between water bodies and to possess live invasive species.