A previously undistinguished species of crayfish has long roamed the floors of Okanagan Lake and other Interior water bodies, a new study has found 鈥� and it needs more research and conservation support.
Findings published May 8 in the scientific journal Zootaxa by an international team of researchers, which includes expertise from the University of Victoria, Royal BC Museum and Fishers and Oceans Canada, highlight that a "highly distinct lineage" of signal crayfish merits recognition as its species: Pacifastacus okanaganensis, or the Okanagan crayfish.
This crayfish varies in colour from olive brown to brick red, measures no longer than 47 millimetres, and seems to exist most often in mid-elevation lakes. Despite the shared genus and similar morphology between Okanagan crayfish and better-known signal crayfish, the researchers focused on Okanagan crayfish's unique origins from certain watersheds.
In fact, several researchers involved were proposing as far back as 2012 that signal crayfish make up more than just one species in the province and beyond.
Okanagan crayfish are native to the Thompson-Okanagan plateau and elsewhere in B.C.'s Southern Interior, ranging north from Okanagan Lake to as far south as Deep Lake, Wash. Populations in B.C. are also known to exist in Idabel Lake near 麻豆精选, Kettle River, Jewel Lake near Grand Forks, and Blueberry Creek near Castlegar.
However, the study notes that just how deep into the U.S. this species exists remains unknown, and goes so far as recommending the Okanagan crayfish be listed as "imperilled" in both B.C. and Washington. Imperilled species are defined as facing a high risk of extinction due to limited range, small numbers and threats from factors such as invasive species.
"We recommend rankings of Imperiled in both British Columbia and Washington because only four or five occurrences of (Okanagan crayfish) are known from each of these jurisdictions," the study explains.
Under the International Union for Conservation of Nature, the researchers also recommend Okanagan crayfish be recognized globally as "data deficient," while the finer details of their occurrence in B.C. and Washington, and their possible displacement by other species, remain unclear.
The researchers say they are concerned about the risk of extinction for Okanagan crayfish posed by invasive non-native species such as rusty crayfish, which don't currently habituate in B.C. but farther south in the Pacific Northwest, and Faxonius virilis crayfish, which were identified in the province last year.
Key to mitigating this risk and kick-starting local conservation will be advocating for Okanagan crayfish as a species distinct from signal crayfish, the researchers add, which while native to B.C. has garnered negative attention internationally due to its invasive introduction to countries such as the U.K.
"A tendency to interpret (signal crayfish) as a uniform, globally cosmopolitan invasive species may leave subspecies, unique lineages, or cryptic species in the native range at risk of population declines or extinctions," they write.
Furthermore, a mix of environmental regulations and awareness around reducing the spread of non-native crayfish such as Faxonius virilis into the Okanagan crayfish range will be instrumental to their longevity, the study concludes.
