So far at invasivore.org, we’ve highlighted several species that have invaded the US from other parts of the world. But the US exports its fair share of invasives as well. Consider, for instance, the Louisiana crayfish, Procambarus clarkii.
In spite of their name, Louisiana crayfish are native to most of the freshwaters surrounding the Gulf of Mexico, including lakes, streams, and wetlands from Texas to Florida. The Louisiana crayfish has, however, played a particularly prevalent role in the French settlement in Louisiana (a timely overview can be found here).
Louisiana crayfish have been introduced around the world, and they are now present on every continent except Australia and Antarctica. Louisiana crayfish have been very successful invaders because they are tolerant of a wide range of environmental conditions including a range of temperatures, salinities, pollution levels, and water currents. They have even been known to travel long distances over land between water bodies. Once introduced, Louisiana crayfish can be virtually impossible to eradicate because of their ability to burrow and hide in the sediment. Moreover, crayfish burrows can themselves be a nuisance, leading to increased erosion and decreases in water levels. Louisiana crayfish are voracious omnivores- eating both plants and animals- so they can devastate native biodiversity.
The Louisiana crayfish provides an excellent example of the “Invasivore’s Dilemma” we have alluded to in several previous posts- it has been moved around primarily because it is such a popular food source. For instance, a Google search for crawfish boil recipe yields over 70,000 results! As I found out when talking to rural farmers in China, farming Louisiana crayfish can be such a lucrative endeavor that environmental and ethical concerns about their release are cast aside.
So what is an invasivore to do? We may be able to do a small part in the global fight against invasive species by catching our own- think of it as an extreme interpretation of the local food movement. We know that that’s not always possible, though, so we also emphasize that education and preventing the further spread of invasive species is essential. Even when sitting with friends around a pot of farm-raised Louisiana crayfish gumbo, a valuable opportunity to discuss the many invasive species issues we highlight here at invasivore.org still exists. So eat up- may invasive species continue to be on your plate and on your mind!