Carcharhinus borneensis (Bleeker, 1858)
Borneo shark
Carcharhinus borneensis
photo by FAO

Family:  Carcharhinidae (Requiem sharks)
Max. size:  70 cm TL (male/unsexed)
Environment:  demersal; marine
Distribution:  Western Pacific: Borneo and China. Questionably occurring in Java, Indonesia and the Philippines. Due to its very restricted and very small area of occurrence (Borneo), conservation measures are urgently needed (Ref. 84280).
Diagnosis:  This small species is characterized by the following: snout long and pointed; slender body and tail; alongside each mouth corner is a row of enlarged hyomandibular pores (5-12); upper anterior teeth finely serrated with a single narrow, oblique cusp; distal edge deeply notched and with several cusplets; lower anterior teeth with narrower, similarly oblique cusps; no lateral cusplets; total tooth row counts 23-26/23-25, or 46-50; second dorsal-fin origin well posterior of anal-fin origin, about opposite or just anterior to anal-fin midbase while second dorsal-fin origin to anal-fin origin 2.2-4.1% TL, 0.4-0.9 times second dorsal-fin base; interdorsal space 20.7-22.7% TL; pelvic fins small, anterior margins 4.4-5.8% TL and 35-42% of pectoral anterior margin; first dorsal fin triangular, with nearly straight posterior margin, free rear tip about opposite pelvic-fin origins, length 14.5-17.6% TL, 1.8-2.4 times height, inner margin 1.9-2.8 in base; second dorsal fin much smaller than first and slightly smaller than anal fin, length 7.5-10.2% TL, base 2.0-3.1 times height; height 21-29% of first dorsal fin height; anal fin height 1.1-1.6 times second dorsal height, base 1.1-1.5 times second dorsal-fin base; total vertebral counts 117-121, monospondylous precaudal counts 33-36, diplospondylous precaudal counts 21-26, diplospondylous caudal counts 56-60, precaudal counts 57-63; colour slate-grey dorsally, whitish ventrally with waterline clearly demarcated along head and body, fins no distinct black markings, pectoral fins and lower caudal lobe with whitish margins (Ref. 84280).
Biology:  A rare species found inshore in coastal areas (Ref. 244). Viviparous (Ref. 50449). Specimens range in length from 23.7-61.8 cm TL. Two specimens collected in the 1800s had fresh umbilical scars at 23.7 and 27.4 cm, indicating that the size at birth is close to these sizes; four specimens of 34.1-37.3 cm had well healed, but still obvious umbilical scars. Five males with lengths of 54.8-57.6 cm were found mature (additional material of mature males with lengths of 59.0-62.0 cm and several pregnant females with lengths of 61.0-65.0 cm). Litter size of pregnant females was 6 (Ref. 84280). Undoubtedly taken in local fisheries (Ref. 244).
IUCN Red List Status: Endangered (EN); Date assessed: 01 October 2005 (C2a(ii)) Ref. (123251)
Threat to humans:  harmless
Country info:   

Entered by: Carpenter, Kent E. - 15.06.92
Modified by: Capuli, Estelita Emily - 05.06.10
Checked by: Luna, Susan M. - 30.03.94

Source and more info: For personal, classroom, and other internal use only. Not for publication.

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