Morphological identification was performed using conventional malacological techniques. Molecular identification was carried out by using
DNA extracted from the shells and periostracum for whole genome amplification (WGA) in combination with PCR and sequencing .
The absence of live organisms during the sampling limited the study to using the shells for the identification. It is unknown if a mortality event had occurred that decimated the freshwater clam populations. Both classic malacological and molecular identification, independently, indicated that the clam is Corbicula fluminea , synonymous of C. malianensis . This species is characterized by a medium-sized bivalve shell, sub-triangular, subequilateral of moderate thickness, black to dark brown near the edge of the shell and yellowish brown on the umbo. Genus specific primers for the cytochrome oxidase subunit 1
gene of Corbicula spp. yielded 401 bp
(Fig 1) fragment with a sequence identity of 100% to C. fluminea (GenBank: KT893369.1) from the Yangtze River Basin.
This is the first record of this invasive species in Ensenada, Baja California confirmed by conventional taxonomy and molecular methods. The molecular identification using the WGA approach as was performed in this study could prove useful for the identification of dead mollusks were limited nucleic acids are available.
An interesting po tential application that arises is use of this species to aid in biomonitoring and bioremediation of the environment as filter feeder.
In addition, it could also be used as a source of food, as is currently being exploring in Malaysia.