Two species on the invasive species watchlistBighead CarpLike many invasive species, bighead carp were originally brought to the U.S. with good intentions in mind. However, this carp species has proven again that there are consequences to introducing an exotic species into an ecosystem. With high flooding in the Midwest in 1993, some carp escaped stocking ponds and entered the Mississippi River. Since that time, bighead carp have spread through the Mississippi into conjoining rivers such as the Illinois, and recently the Missouri.Illinois-Indiana Sea Grant has compiled a fact sheet on the bighead carp. Northern SnakeheadThe snakehead is a predacious fish brought to North America from Asia. Snakeheads are aggressive predators known to feed on a variety of species, occasionally including mammals. The snakehead feeds high on the food chain, and is therefore a danger to many of the native game fishes of North America. They are a major concern because of their ability to reduce gamefish populations, as well as spread to new habitat. Snakeheads are capable of surviving in bodies of water with low levels of dissolved oxygen, and due to a primitive lung, they can travel over land to reach bodies of water. They have been known to survive up to three or four days out of water. Snakehead adults usually have a dark brown body with large black blotches. Snakeheads can reach more than1 meter in length and 15 pounds.The snakehead should not be confused with the bowfin, a native species to Illinois. The bowfin is the only remaining fish of the Amiidae family, a group originating over 100 million years ago. The bowfin is a very important species in controlling the populations of many small fish species. The bowfin is often confused for the snakehead, due to their close physical resemblance. Distinctive qualities of the bowfin include a large flattened head with tube-like nostrils, long sharp teeth, and a long spineless dorsal fin, extending over the majority itsâ body. The bowfinâs long body is covered with olive colored scales with occasional slight variations in color. Another distinctive feature between the bowfin and snakehead is the anal fin on the two species. On the snakehead, the anal fin is noticeable longer, generally covering about half the length of the body. The bowfinâs anal fin is much shorter, usually only a few inches, or approximately one eighth of the fishes total body length. Also, the pelvic fin of the bowfin is positioned at mid-body while the pelvic fin on the snakehead is further back. The snakehead also has a narrow, pointed head, while the bowfinsâ head is larger and recedes from the body at a slighter angle. As the name implies, the snakeheadâs small head resembles that of a serpent. Click here to see a map of where INHS has collected the bowfin. For more information on the fishes of Illinois, visit Illinois DNR's website. Exotic species of many types pose threats to the ecological well being of native species and their habitats when introduced into ecosystems. When either the bighead carp or the snakehead is encountered, it is recommended that their presence be reported to wildlife officials, and they are not released back into the habitat they were found in. The Illinois Department of Natural Resources can be reached at (217)-782-6302. | |
