A team of researchers from Czechia has identified a new species of freshwater crayfish that is sold as a pet under the common name of “blue moon crayfish”. The new species, named Cherax woworae or the steel blue crayfish, has a distinctive steel blue color with marbled sides and multi-colored claws. It is native to the western coast of New Guinea, but has also been found in thermal waters in Hungary, where it was probably released by irresponsible hobbyists.
The origin of the steel blue crayfish
The researchers acquired several specimens of blue crayfish from a pet trader who specialized in ornamental aquatic animals. They noticed that the crayfish had different morphological features and color patterns, and decided to conduct a detailed study to determine their taxonomic status. They compared the specimens with other known species of Cherax, the genus of freshwater crayfish that are endemic to Australia, New Guinea and some adjacent islands. They also performed DNA analysis to assess the genetic divergence among the specimens and other related species.
The study, published in the journal Zootaxa on August 10, 2023, revealed that the specimens belonged to five distinct species of Cherax, four of which were already described in previous studies. However, one of the species was new to science and was named Cherax woworae after Daisy Wowor, a crustacean scientist and curator at the Museum Zoologicum Bogoriense in Java, Indonesia. The new species is moderately-sized, reaching about 2 inches in length and just under an inch in width. It has two equal-sized claws that change from turquoise blue to peachy orange to black from arm to tip. Its body has a steel blue color with marbled sides and an orange-tipped tail.
The distribution and conservation of the steel blue crayfish
The researchers traced the origin of the steel blue crayfish to the western coast of New Guinea, the Indonesian side of the island. They suggested that the species is likely distributed along the northern coast of Papua province, from Jayapura to Sorong, and possibly also in some inland areas. However, they noted that field surveys are needed to confirm the exact range and habitat preferences of the new species.
The researchers also reported that they found a population of steel blue crayfish in thermal waters in Hungary, where they were probably introduced by pet owners who released them into the wild. They warned that such introductions pose a serious threat to the native biodiversity and ecosystem functioning, as well as to human health and economy. They urged hobbyists to refrain from releasing exotic crayfish into natural waters and to dispose of them responsibly.
The researchers also highlighted the need for conservation measures to protect the steel blue crayfish and other Cherax species from overexploitation and habitat loss. They pointed out that freshwater crayfish are popular ornamental animals in the pet trade, as well as food sources for local people in some regions. They estimated that millions of crayfish are collected from Indonesia every year and exported to Europe, North America and Japan. They called for more research and education on the diversity and ecology of these fascinating creatures, as well as for stricter regulations and enforcement on their trade and transport.