Posts Tagged crayfish
Bait bucket introductions is perhaps an unusual term to some of you, however this is the most common means of spreading aquatic invasive species within the state. You can help Missouri’s lakes, ponds, rivers, streams and protect our waterways by destroying unused bait or throwing it in the trash—not in the water. This simple practice can keep invasive species from colonizing new waters, and turning our local waters into a virtual nightmare.
Non-native or non-local species are frequently larger, more aggressive and more fertile than local native species. Their habits can also be more destructive, and they often lack local predators or other natural controls. The rusty crayfish is a good example of a species that became invasive when it was moved from its native Ohio River basin drainage, largely via bait buckets. The rusty crayfish is larger than most native Missouri crayfish, so it outcompetes them, and its size makes it unattractive prey for many fish. It also destroys the aquatic plant beds that serve as cover and food for other aquatic organisms, as well as nursery habitat for sport fish. In addition, rusty crayfish prey on fish eggs, further harming local fish populations. Other bait crayfish, including native Missouri species that are moved from one water body to another, have caused similar problems.
Rusty crayfish are larger than most Missouri native crayfish and their claws are larger in comparison to their bodies than most native species. Key characteristics include: Rusty patches on the back of the carapace which look like someone picked the crayfish up with brown or reddish paint on their fingers, and black-tipped claws which may have some red or orange on the very tips.
If a crayfish resembling the rusty crayfish is found, please save 1-4 specimens by freezing them in a zip-lock bag. Report this find to MDC biologist Al Buchanan by calling 573-882-9909. He will make arrangements to send them to an expert for positive identification.
First posted on 11-27-2009
At least three individuals have contracted a lung parasite after eating raw crawfish from rivers in southern Missouri. The Missouri Department of Health and Senior Services along with the Missouri Department of Natural Resources has issued a warning to not eat raw crawfish.
Crayfish, crawfish or crawdads contain parasites that can cause severe lungworm disease in people and animals. Cooking crawfish kills the parasite and makes the invertebrate edible for humans.
The Missouri individuals contracted the parasites by eating raw crawfish from a tributary of the Meramec River and another from the Current River. There are no reports of anyone contracting the parasites in Arkansas. These particular parasites have a life cycle that involves snails, crayfish and mammals.
Before eating crawfish, people should make sure they are adequately cooked. Symptoms associated with lung disease include fever, difficult or labored breathing, chronic cough, coughing up blood and abdominal pain. However, many infections can go unnoticed, or result in only mild symptoms. The disease may also involve other areas of the body such as the spleen, abdominal cavity, skin, brain and central nervous system. If the disease is contracted, symptoms usually last about five years. These symptoms tend to subside after five years, but they have been known to persist for as long as 20 years.