Scoliodon macrorhynchos


Pacific spadenose shark
Characteristic features:
Colour:

Dorsal surfaces bronze to greyish, fading to grey after death. Pectoral, pelvic, anal and lower caudal-fin tips and pectoral-fin posterior margins pale; upper lobe of caudal edged with black and with a dusky tip. Ventral surfaces white.

Size:

Maximum size up to 100 cm TL; birth size 31–39 cm TL.

Distribution:

Found in the eastern Atlantic and Indo–west Pacific.

Habitat:

Found throughout the water column, usually near the bottom, on coastal and continental shelves. From close inshore to depths of at least 200 meters.

Biology:

Feeds primarily on small bony fish, and also crustaceans and cephalopods. Populations appear to have increased in some areas where there have been declines in large inshore sharks (e.g. South Africa). Regional differences in some DNA sequences suggest this may represent a complex of species. Length at maturity is 70–81 cm TL and 68–72 cm TL for females and males respectively. Age at maturity is around 1.8 years for females and 1.1 years for males. Reproductive mode is viviparous with yolk-sac placenta; females give birth to 1–8 (usually 2–5) pups after a gestation period of about 12 months. Females have no reproductive seasonality and probably give birth each year. Maximum age of northeastern Australian populations reported for females and males as 8.1 and 4.5 years respectively.

Indonesian fisheries:

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

Similar species:

Loxodon macrorhinus
Sliteye shark

Loxodon macrorhinus differ in having a posterior notch on eyes (vs. no notches present); pectoral fins narrow (vs. broadly triangular) and posterior margin of caudal fin deeply incised (vs. shallowly concave).

Rhizoprionodon spp.

Rhizoprionodon acutus
Rhizoprionodon acutus

Rhizoprionodon spp. differ in having head slightly depressed, when viewed side on (vs. very depressed); first dorsal-fin free rear tip over or anterior to pelvic-fin origins (vs. about over midbases of pelvic fins) and posterior margin of caudal fin deeply incised (vs. only shallowly concave).

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