Fig. 1. Aggregation of dead Fluted Giant Clam shells (foreground).
Fig. 2. Close-up view of the Fluted Giant Clam shells in the pile.
(Photos by Loh Kok Sheng)

Fluted Giant Clam (Tridacna squamosa) shells ‘graveyard’ at Semakau Landfill

Location, date and time: Singapore Straits, northern part of Semakau Landfill; 1 February 2014; 1800–2000 hrs.

Observation: Giant clams have been an important coastal resource to man as food and for materials across the Indo-West Pacific region (Mingoa-Licuanan & Gomez, 2002). In Singapore, exploitation of giant clams was evident based on early accounts from European travellers (Traill, 1847) and of local fishing practices (Chuang, 1961; Purchon & Purchon, 1981). Physical evidence of exploitation was also discovered during archaeological excavations, where aggregations of tridacnine shells were found at sites previously located along the old coastline of mainland Singapore (Neo & Todd, 2012).

This record adds to the exploitation history of giant clams in Singapore (Neo & Todd, 2012), and represents the largest assemblage of mature shells found so far. The species of interest, Tridacna squamosa, is one of the five species that can still be found in Singapore, but is locally critically endangered (Neo & Todd, 2013). This intensity of exploitation is unsurprising as there have been early accounts of larger clams being preferentially harvested (Harrison & Tham, 1973; Chou, 1984). Such exploitation could explain the current population status — sparsely distributed with few mature individuals, coupled with poor recruitment rates (Neo et al., 2013).

References:

  • Chou L. M., 1984. The coral reef of Pulau Salu. Singapore Scientist. 10 (2): 60–64.
  • Chuang S. H., 1961. On Malayan Shores. Muwa Shosa, Singapore. xvi + 225 pp., 112 pl.
  • Harrison, J. L. & A. K. Tham, 1973. The exploitation of Animals. In: Chuang S. H. (ed.). Animal Life and Nature in Singapore. Singapore University Press. Pp. 251–259.
  • Mingoa-Licuanan, S. S. & E. D. Gomez, 2002. Giant clam conservation in Southeast Asia. Tropical Coasts. 3: 24–56.
  • Neo M. L. & P. A. Todd, 2012. Giant clams (Mollusca: Bivalvia: Tridacninae) in Singapore: history, research and conservation. Raffles Bulletin of Zoology. 25: 67–78.
  • Neo M. L. & P. A. Todd, 2013. Conservation status reassessment of giant clams (Mollusca: Bivalvia: Tridacninae) in Singapore. Nature in Singapore. 6: 125–133.
  • Neo M. L., P. L. A. Erftemeijer, J. K. L. van Beek, D. S. van Maren, S. L.-M. Teo & P. A. Todd, 2013. Recruitment constraints in Singapore’s Fluted Giant Clam (Tridacna squamosa) population – A dispersal model approach. PLoS ONE. 8 (3): e58819. doi:10.1371/journal.pone.0058819
  • Purchon, R. D. & D. E. A. Purchon, 1981. The marine shelled mollusca of West Malaysia and Singapore: Part 1. General introduction and an account of the collecting stations. Journal of Molluscan Studies. 47: 290–312.
  • Traill, W., 1847. A few remarks on conchology and malachology, comprising brief notices of some of the more remarkable “Testacea” in Singapore and its neighbourhood; with an appended catalogue of Singapore shells arranged in conformity with Lammarck’s System. The Journal of the Indian Archipelago and Eastern Sea. 1 (5): 225–241.

Source: Singapore Biodiversity Records 2014: 248-249

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