Daily Decay (2nd February 2018)


Daily Decay (2nd February 2018): Green Mussel (Perna viridis) and Acorn Barnacles (Balanomorpha) @ Coney Island (Pulau Serangoon)

Flower Crab (Portunus pelagicus) with Parasitic Barnacle (Diplothylacus sinensis)
Changi, 8th January 2017

The yellow capsules on the underside of the Flower Crab are egg sacs of a Parasitic Barnacle that has infected it, and lives as an internal parasite. It’s not known if the death of this Barnacle and its Crab host were connected to the oil spill that has affected parts of Changi’s shores.

The Parasitic Barnacle (Diplothylacus sinensis) is referred to in some references as Thompsonia dofleini, a synonym.

For more information on the Flower Crab:

For more information on Parasitic Barnacles:

Acorn Barnacles


Acorn Barnacles (Balanus sp.)
Sengkang Riverside Park, 27th November 2010

These empty shells of Acorn Barnacles were found on a concretised section of the riverbank at Sungei Punggol. In the past, this stretch would have been subject to the ebb and flow of the tides, and the water must have been sufficiently salty to sustain some marine organisms. However, with the subsequent damming of the river mouth to form Punggol Reservoir, the salinity has presumably dropped, killing off those organisms unable to survive in freshwater. These dead barnacles, and the mangroves that still grow along the riverbank, hence represent a time not very long ago, when the sea still exerted significant influence over aquatic life in the former estuary.