Grey sharpnose sharkRHX

Rhizoprionodon oligolinx

ventral head Rhizoprionodon oligolinx
Rhi.oli. I-upper tooth

Characteristic features:

  • Second dorsal-fin origin opposite anal-fin insertion
  • Anal fin larger than second dorsal fin, its posterior margin shallowly concave
  • Preanal ridges very long, about equal to length of anal-fin base
  • Snout long and narrowly rounded
  • Upper labial furrows very short, less than 1% of TL
  • 15 – 22 enlarged pores in total from each side near mouth corners
  • Teeth with narrowly triangular, smooth-edged, oblique cusps

Colour:

Dorsal surfaces bronze to greyish, fading to grey after death. Pectoral-fin posterior margins pale; upper lobe of caudal edged with black. Ventral surfaces white.

Size:

Maximum size up to 70 cm TL; birth size 21 – 26 cm TL.

Distribution:

Found in the Indo–west Pacific, from the Persian Gulf to northern Australia and northwards to southern Japan.

Habitat:

Found inshore and offshore on coastal and continental shelves; to depths of at least X meters.

Biology:

Feeds consists of small bony fish, and also crustaceans and cephalopods. Length at maturity is 32 – 41 cm TL and 29 – 38 cm TL for females and males respectively. Reproductive mode is viviparous with yolk-sac placenta; females give birth to 3 – 5 pups after unknown gestation period in January and February off Mumbai in India. Maximum age is unknown.

Indonesian fisheries:

Commonly caught by inshore demersal gillnet fisheries, especially off Java. Utilised for its fins and meat, but of limited value due to its size.

Similar species:

Rhizoprionodon acutus
Milk shark
Rhizoprionodon acutus
Similar to Rhizoprionodon acutus, but differs in having very long and prominent upper labial furrows (vs. very short).
Rhizoprionodon taylori
Australian sharpnose shark
Rhizoprionodon taylori
Similar to Rhizoprionodon taylori but, differs in having 7 – 16 enlarged pores in total near mouth corners (vs. 15 – 22 enlarged pores near mouth corners).

External links:

FishBase
The IUCN Red List of Threatened SpeciesTM