The invasive Caribbean bivalve Mytilopsis sallei (dreissenidae) introduced to Singapore and Johor Bahru, Malaysia

Abstract

Mytilopsis sallei (Récluz) was present at densities of up to 830 individuals. 100 cm-2 in nine of 20 tidal monsoon canals surveyed in Singapore. They formed a broad, extensive, densely populated band on vertical and sloping concrete walls as well as on the floor of monsoon drains, up to several kilometres inland from the sea. The bivalve was also present in high densities in a river (Sungei Sekudai) in Johor Bahru. Size-frequency plots showed continuous recruitment at two locations, whereas intermittent recruitment with single or multiple cohort peaks were seen at five other sites studied. The survey results suggest that M. sallei is thriving over a fairly wide salinity range in a man-made habitat, making it an excellent candidate for permanent residence, particularly as it is now widely distributed both here and in Johor Bahru. © National University of Singapore.