The first evidence for genetic differentiation of a non-native false mussel Mytilopsis sallei (Récluz, 1849) in southern Thailand

The false mussel Mytilopsis sallei (Récluz, 1849) is a bivalve indigenous to the tropical western Atlantic that has become invasive in Southeast-Asia. Establishment of M. sallei populations in Thailand was reported in 2008 and it has spread to several locations along both the Gulf of Thailand and Andaman Sea coasts. The survival of planktonic larvae of M. sallei in oceanic salinity is known to be poor so these populations may be a result of multiple introductions, and propagule exchanges between populations may be limited. To test this, we investigated the variability of cytochrome oxidase subunit I in M. sallei within and between spatially isolated locations, as well as between the Gulf of Thailand and Andaman Sea coasts. In total, 407 base pairs from 60 individuals across five locations were analysed. Differences in the genetic structure of M. sallei among the five populations from southern Thailand suggest that there is no connectivity between the Gulf of Thailand and Andaman Sea populations. The results revealed the presence of six of the 15 haplotypes known among Southeast-Asian populations of M. sallei. This study contributes to the understanding of population genetic structure of the non-native false mussel, M. sallei, in Southeast-Asia.