NATURE IN SINGAPORE 2009 2: 167–169 Date of Publication: 28 April 2009 © National University of Singapore OBSERVATIONS ON THE BLACK POMFRET, PARASTROMATEUS NIGER (TELEOSTEI: PERCIFORMES: CARANGIDAE) H. H. Tan Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore, Blk S6, Science Drive 2, #03-01, Singapore117546, Republic of Singapore (Email: heokhui@nus.edu.sg) INTRODUCTION The black pomfret, Parastromateus niger (Bloch), is an economically important fish in Singapore, and is commonly offered for sale in wet markets, commanding a mid-price range of around S$8.00–20.00 per kg (size-dependent). The body of the black pomfret is laterally compressed and of an elongated diamond shape. All parts of the body and fins are uniformly dark grey. The head is blunt with a terminal mouth. The pectoral fin is slender and sickle-shaped and extends beyond the mid-body. Both dorsal and anal fins are triangular, and with a low profile. The caudal peduncle is very slender with a series of small scutes and the caudal fin is forked. Pelvic fins are present in juvenile fish, but absent in specimens larger than 100 mm in total length. Although it can attain 550 mm in standard length, most fish seen in the market are smaller (Carpenter & Niem, 1999; Fig. 1). The black pomfret is a midwater pelagic species that occur over muddy bottoms in coastal areas (Lim & Low, 1998). All black pomfrets are wild-caught, usually by trawling or gillnetting from the South China Sea. It is occasionally caught in drift nets off the northern coast of Singapore, along the Straits of Johore (pers. obs.). Fig. 1. Parastromateus niger, dead specimen (not preserved), about 350 mm standard length, Johore Straits. Owing to the similarities in body shape, the black pomfret is often thought to be related to the white and Chinese pomfrets (Pampus argenteus and Pampus chinensis, respectively). However, they belong to different families ― the white and Chinese pomfrets to the family Stromateidae, and the black pomfret to the family Carangidae. In fact, the black pomfret is unusual for members of the Carangidae, compared to other members such as the bigeye trevally 167 Tan: Observations on Black Pomfret Fig. 2. Live Parastromateus niger in a floating cage of a kelong in the Johor Straits, photographed from above. (Caranx sexfasciatus) and ikan kuning (Selaroides leptolepis), because they typically have torpedo-shaped bodies. Both the white and Chinese Pomfrets lack pelvic fins at all stages of life, whereas the black pomfret has a pelvic fin in younger specimens shorter than 100 mm in total length. In adition, the small scutes along the caudal peduncle of the black pomfret are absent on white and Chinese pomfrets (Carpenter & Niem, 1999). OBSERVATIONS On 16 Jul.2004 at around 1900 hours, while at one of the kelongs (off-shore palisade trap with accompanying floating cage farm) on the Johore Straits along the north coast of Singapore near Pulau Ubin, I had the opportunity to observe a small school of 10–15 black pomfrets in a floating cage. The fish were caught in the palisade trap at the kelong, and then placed in adjacent floating cages where they could be reared to a marketable size. The colouration of living black pomfret is very different from dead market specimens (compare Figs. 2 and 1). Live specimens have a silvery, steel-grey body, with four narrow white bars spaced at regular intervals along the flanks, with the first bar located just behind the opercle. The belly area is whitish. The dorsal fin is yellow and the anal fin is pale yellow. and both fins having a narrow black margin. The pectoral fin is hyaline and the caudal fin is whitish. The swimming behaviour of black pomfrets in the cage is interesting, and unlike other carangids. The fish swims on its side with its dorsally oriented pectoral fin erected like a sail (Fig. 2). This behaviour has been documented for this 168 NATURE IN SINGAPORE 2009 species swimming near the water surface (Carpenter & Niem, 1999). This atypical swimming behaviour may play a role in its choice of food―plankton and small pelagic invertebrates which migrate to shallow waters at night. ACKNOWLEDGEMENTS I am grateful to the National Parks Board and Housing Development Board for granting permission and generous support to survey the northern shores of Singapore. I also thank Oung Hock Lim, Yusfiandi bin Yatiman, Kelvin Lim, and Tommy Tan, for field assistance. LITERATURE CITED Carpenter, K. E. & V. H. Niem (eds.), 1999. FAO Species Identification Guide for Fishery Purposes. The Living Marine Resources of the Western Central Pacific. Volume 4. Bony Fishes Part 2 (Mugilidae to Carangidae). Food and Agriculture Organization of the United Nations, Rome. Pp. 2069–2790. Lim, K. K. P. & J. K. Y. Low, 1998. A Guide to Common Marine Fishes of Singapore. Singapore Science Centre, Singapore. 163 pp. 169