AAGB

Labyrinths on Bintan Island, Sumatra

by David Armitage

AAGB members and Singapore University students, Swee Hee Tan and Heok Hui Tan visited 40 sites on Pulau Bintan in April 1992 and May 1993. This is part of the Riau archipelago is part of Sumatra, Indonesia and just south of Singapore and peninsular Malaysia. Pulau Bintan is being rapidly developed as a beach resort so the vegetation is already badly disturbed and the few patches of forest are secondary end even these are surrounded by plantations.

Seven anabantoids (includingLuciocephalus, the pikehead) and 5 snakeheads were found on the island. The snakeheads were C.striata, C.lucius, C.gachua, C.melasoma andC.bankanensis. As well as the ubiquitousTrichogaster trichopterus, the 3 spot gourami, and Anabas, the climbing perch, 4 species of Betta were found including the recently-described B.miniopinna, a dwarf of the B.coccina group and allied toB.persephone from southern peninsular Malaysia. This appeared to be the only bubble-nester as the remaining species,B.pugnax, B.spilotogena (a big, yellow Betta and part of the B.waseri group) and, intriguingly, B.edithae are all mouthbrooders. While all the other species may be found in Malaysia, B.edithae is normally associated with Indonesia. In Bintan, it came from open-country flowing streams next to secondary forest and rice-fields. Heok Hui Tan noted that the female laid secondary eggs for the free-swimming young to consume.

Four specimens of a Parosphromenus(liquorice gourami) sp., resemblingP.deissneri from Banka, were found in open waters in degraded secondary forest over clay and laterite substrate in water of pH 5.8. Like B.miniopinna and B.spilotogena, this is normally a blackwater species which indicates that peat swamp habitats once existed on Pulau Bintan.

References

1.  Tan, S.H. and Tan, H.H. 1994. The freshwater fishes of Pulau Bintan, Riau archipelago, Sumatera, Indonesia. Tropical Biodiversity 2, 351-367.

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