Multiplex PCR for species-level discrimination of Yellow Lampmussel (Lampsilis cariosa (Say, 1817)) and Tidewater Mucket (Atlanticoncha ochracea (Say, 1817))

Abstract

Effective management of imperiled freshwater mussel populations (Order Unionida) is dependent on accurate field identifications. Standard methods of identifying living mussels utilizing external shell characteristics, however, can be unreliable for some species given high levels of phenotypic plasticity and morphological overlap with other taxa. In Canada, Yellow Lampmussel (Lampsilis cariosa (Say, 1817)), a species of Special Concern, is limited in distribution to isolated populations within Nova Scotia and New Brunswick. Efforts to monitor this species can be complicated by difficulties in distinguishing Yellow Lampmussel from the Tidewater Mucket (Atlanticoncha ochracea (Say, 1817)). Both species are known from the Saint John River and its tributaries in New Brunswick and are also sympatric within the Sydney River watershed in Nova Scotia. In our survey of biology students and faculty at Cape Breton University, participants correctly identified these two species based on photographs of external shells only 61.7% of the time, with even the most experienced individuals achieving a success rate of just 68.8%. To facilitate species-level identification, here we have developed a simple genetic-based tool to differentiate between live Yellow Lampmussel and Tidewater Mucket. Using custom-designed primers and a single multiplex PCR reaction, the identity of these two species can be determined based on amplification product size. This tool should be of enormous value to freshwater mussel ecologists working to monitor Yellow Lampmussel populations and to explore other aspects of their biology and ecology.