An invasive species that is becoming a problem in North American waters is the Asian carp. An invasive species is one that originates elsewhere and invades a new geographical location. When it enters the new location, there are no natural predators. Thus, the invasive species competes with local species for food and the invasive species may eat the locals “out of house and home.” Invasive species have the potential to destroy an ecosystem if a solution is not found.
When it comes to the Asian carp, which were originally brought over from Asia to clean water treatment ponds, and which then escaped those ponds during periods of flooding, there are no natural predators. There are no North American fish species large enough to eat adult Asian carp. The only predators noticed so far are eagles and white pelicans, which may eat smaller carp. Largemouth bass may eat juvenile carp. However, the carp are prolific and can rapidly outstretch the abilities of predators to eat them.
Other factors that may determine and limit the growth of the Asian carp population is the availability of food, the conditions necessary for spawning, and how easy it is for the young to survive. While it is known the Asian carp are filter feeders and eat algae, and thus may not be able to survive in colder lakes, still no one knows for sure how prolific they will be in lakes.
They have successfully established themselves in Midwest rivers, and have been noticed in Lake Michigan. If consistently young and older fish are caught in Lake Michigan, then it indicates that the carp are successfully multiplying. While the carp have invaded the Mississippi waterways, and have travelled from connecting river to river, they have only recently been found in Lake Michigan.
This is of great concern as the carp can damage the ecosystem there which contains many endangered species. It can also damage the recreational sports there, as boat motors startle the fish causing them to leap. The fish grow so large, that when they leap, they may jump into boats and injure boats or people.
One way of determining how many of these fish have invaded Lake Michigan involves electrofishing, where fish are temporarily stunned and brought to the surface to determine and count fish populations. Another means is DNA sampling. DNA can be released in the form of urine or feces from the carp, and if collected soon enough after release, can be used to determine the presence of these fish.
Asian carp are definitely a problem that has invaded more and more waterways. It is something fishermen, Fish and Game Departments, and lake management companies will have to deal with in the days to come.