Southeastern rivers and streams have more species of aquatic animals—fishes, mussels, turtles, and salamanders—than anywhere else in the country. Hiding in all of this diversity, however, are alien species--an animal or plant that has been introduced through human activity outside of its native range. Many species that we commonly seen in Tennessee, like bighead carp or even redbreast sunfish, are not native to this region.
Alien species may also be known as nonnative, invasive, introduced, or nuisance species. There are several ways that a species may be introduced into a waterway outside of its native range. Sometimes humans put them there on purpose, such as stocking fish that are popular for recreational and sports fishers. Sometimes nonnative species are introduced by well-intentioned people releasing fish from their home aquariums without thinking about the impact on the environment. Some introductions happen unintentionally. Commercial shipping is a major transporter of invasive species in U.S. bays, major rivers, and the Great Lakes. Ships will take in water, called ballast water, in one area to maintain balance as they travel across oceans and rivers. There are almost always small organisms in that water. When ships reach their destination, they release the water, and with it, any organisms that were taken in at the original port. Many shipping ports now have regulations about releasing ballast water, but this has historically been a major pathway for introductions of nuisance species in the Great Lakes.
Over the next few weeks, we will highlight some different invasive freshwater species and their impact on both humans and the environment. Most are species that can be found in the Chattanooga area, Tennessee, and the southeastern United States. Stay tuned!
Redbreast sunfish (Lepomis auritus) is one of the many invasive aquatic species found in Tennessee waterways. From http://fish.dnr.cornell.edu/nyfish/Centrarchidae/redbreast_sunfish.html
3 comments:
Cool beans! Thanks for the info!! :)
Anyone who follows the history of ballast water should realize that after Senator Boxer killed legislation in 2008 passed in the House 395-7, to protect us from ballast water our politicians have been caving in to foreign shipping which constitutes the majority of flag ships in US waters. They currently have discussions going on in Congress concerning the economic problems this would create for shipping. California's action reversing their stance for tough regulations despite Senator Boxers claim that the legislation she killed for the whole country was not strong enough, points out the political game they are playing with American health an environment. Not a single piece of new legislation has been introduced in Congress by either party since, and the EPA had to be sued to even address the idea of creating a standard. Our President as commander and chief, three years after allegedly supporting congressional legislation in 2008 has done nothing but allow a continuous delay on Coast Guard standards, the latest being a delay to "correlate" ( after the next presidential election) with a yet undeveloped EPA standard. New York's governor, as attorney general developed their purposed tough standards and has now delayed them in conjunction. It is about our dependence on foreign manufactured products to bolster our economy, and sadly although America was capable of putting a man on the moon, because shipping interest say that: " technology is not out there " significant action will probably never be taken. What ever weak action is taken environmentalist will have to accept and new shipping investments to develop a fix for the problem will be minimal as they know the political will is gone the same as many of the politicians who did care, Granholm, Schwarzenegger, Patterson, Strickland, Oberstar, etc. Interesting with the political help of our President, Senator Boxer the person responsible for killing national ballast water legislation was reelected. Not surprising since the issue of ballast water is never public-ally broad cast by the news media, despite the severe affects the way it is handled will affect both, Americans and the worlds health and environment forever. The ironic travesty will be the way some who claim to care about environmental stewardship along with the shipping interest will portray weak action with respect and decorum as a great achievement, further destroying a chance for future significant actions. Shipping has won as this problem is not even close to being solved.
Thank you for your comment Don M. The transfer of invasive species via ballast water is a loaded issue. For more information, visit the link below. It is an NPR story about invasive species in San Francisco Bay, protests from various sectors, and some possible solutions being proposed.
http://www.npr.org/2011/05/11/136212105/foreign-species-invade-san-francisco-bay
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