Clone Colonization – Canada’s Newest Invasive Species

Thirty years ago, marbled crayfish simply did not exist. Spontaneously appearing in the German aquarium trade in the 1990’s, this species became genetically isolated from its closest relative through a sudden mutation. Whereas most crayfish have two complete sets of chromosomes, the marbled crayfish has three. Somehow avoiding defects from the extra DNA, the mutation granted marbled crayfish a new ability that made them one of the most unique species in science – the ability to clone itself. Parthenogenesis, a reproductive method not found in any other decapods, allows the all-female population to induce eggs without mating, birthing hundreds of identical clones.
Despite originating within the last thirty years, the marbled crayfish has quickly become a global threat to endemic species. Its voracious appetite, large size and ability to clone itself means that only one individual is required to establish an invasive population. Today it has colonized most of central Europe, and can be found as far as Israel, Japan, Madagascar and now…Canada.
Discovered in a Burlington pond this summer, the marbled crayfish has finally arrived in Canada, threatening the already at-risk populations of endemic crayfish.