Self-Reproducing Crayfish Species Threatens Ecosystems Around the World
A study published by Nature Ecology & Evolution warns of the rising threats of a self-cloning and all-female specie of crayfish due to its rapidly expanding population. The marbled crayfish, or the marmorkreb, is threatening local ecosystems across Europe and now various other countries where it was introduced.
The species did not exist until about 25 years ago, as a result of genetic mutation. In 1995, a slough crayfish was captured in the Everglades and purchased by a German hobbyist; that single crayfish experienced a genetic mutation that resulted in gaining an additional set of chromosomes, allowing it to asexually reproduce through a process called parthenogenesis. All the subsequent female offspring are then able to clone themselves without male fertilization.
While most organisms have two sets of chromosomes, one from the father and one from the mother, the marbled crayfish has three sets. Researchers have posited that this has allowed the marbled crayfish to adapt to various environments by expressing different parts of their large and diverse genomes in different regions.
The original owner was unable to care for the numerous offspring and began offering them to friends, local aquariums and pet stores. This led the marbled crayfish to spread across Europe as pets. However, as their reproductive rates began to overwhelm the new owners, many resorted to dumping them into local rivers and the species became invasive.
The marbled crayfish was later introduced as a source of cheap protein for the people of Madagascar, but the rapidly-reproducing population and the ability to survive almost any kind of environment have caused it to quickly outcompete local crayfish species and allowed it to devastate the local ecosystem.
The marbled crayfish is banned from being produced, distributed, or sold in the European Union due to its invasive nature. While there are no reported wild populations in Canada and the United States, the marbled crayfish can be easily found in stores and online retailers.
Despite having no reported wild populations, both Canada and the United States have bans regarding releasing invasive species into the wild. Two states, Missouri and Tennessee, have also preemptively banned the species completely.
Researchers have compared the marbled crayfish’s replication and survival techniques with those of cancer cells. Scientists at the German Cancer Research Centre are trying to study the crayfish in order to learn how cancer cells can replicate so rapidly and adapt to survive against drug treatments.