brought into holding tanks by a ship to add stabilizing weight before the ship loads cargo. When the ship is going to load and unload the cargo, it releases the ballast water at the port of entry in order to offset weight and navigate shallow port waters. It was estimated that nearly 99 percent of U.S. overseas trade is transported over water, and more than 80 million tons of ballast water, and the thousands of foreign species in it, are released into U.S. waters every year. Not all the species in ballast water can survive life in the holding tanks or are a threat to local environments, but since the species composition in ballast water is variable, unpredictable, and innumerable, the potential for introducing harmful species remains high. Social Aquarium and Ornamental Trades NISA specifically identifies ballast water as a source of aquatic nuisance species, but another substantial source is from the aquarium and ornamental industry, which is worth $25 billion per year. Aquarium species are considered to be stronger than ballast water species, because they are typically traded as healthy adults capable of reproduction. Owners of exotic species may release them for a variety of reasons, including boredom, species aggression, or having to move. The United States trade of aquarium species involves over 2000 species and about 150 million exotic freshwater and marine fishes from all over the world. Regulation of this industry is not very stringent; the ease of the Internet has allowed trade to grow and federal and international policies lack teeth. Governments also do not want to hinder trade, and aquatic hobbies are sometimes promoted as environmentally-friendly, which can be attractive to certain groups. Fishermen The activities of fishermen have been blamed for introducing and spreading invasive species into aquatic environments. Algae can stick to the bottoms of boots and get transported from site to site. This was the case in Maryland, where invasive algae were found on the soles of felt-soled fishing boots in 2011. Bait is another source of invasive species introduction. In Kansas City, fishermen were unwittingly using the invasive species Asian carp as bait. Asian carp is a well-known aquatic nuisance species whose presence is felt throughout the United States. In addition to competing for food sources against native species, the Asian carp can pose a large threat to human recreation: an adult carp can be so large that it can actually