Remains or moult of Chinese Mitten Crab at the bottom of the pond, surrounded by numerous Faunus ater snails. Note detached and overturned carapace at upper right corner of picture. Photograph by Tan Heok Hui
Chinese Mitten Crab (Eriocheir sinensis) at West Coast marsh pond
Location, date and time: Singapore Island, marsh pond at West Coast Park; 26 November 2014, 0930 hrs.
Observation: A large male Mitten Crab with detached and overturned carapace (about 10 cm wide) was seen in a shallow part of the pond. It was surrounded by many Faunus ater snails (see Lok et al., 2011, for information on this snail). As can be seen on the accompanying photograph, the empty body cavity and intact limbs suggest that it is a moult, and the actual crab could be somewhere in the pond. It can also be a crab that had died and been eaten. However, the actual condition of the animal has not been confirmed.
Remarks: The Chinese Mitten Crab has been recorded as an invasive species in many places, and in Singapore an individual was previously recorded in the wild (Low et al., 2013). The present record coincides with the northern hemisphere autumn, the season in which gravid Mitten Crabs are imported as a seasonal delicacy. It is highly likely that this example had been bought alive from a supermarket and intentionally released at the pond.
Lok, A. F. S. L., W. F. Ang, P. X. Ng, B. Y. Q. Ng & S. K. Tan, 2011. Status and distribution of Faunus ater (Linnaeus, 1758) (Mollusca: Cerithioidea) in Singapore. Nature in Singapore. 4: 115-121.
Low B. W., N. K. Ng & D. C. J. Yeo, 2013. First record of the invasive Chinese mitten crab, Eriocheir sinensis H. Milne Edwards, 1853 (Crustacea: Brachyura: Varunidae) from Singapore. Bioinvasions Records. 2 (1): 73-78.