Shortfin makoSMA

Isurus oxyrinchus

Isu.oxy Secondary
Isurus oxyrinchus upper and lower teeth

Characteristic features:

  • Strong lateral keel on caudal peduncle
  • Snout sharply pointed, its undersurface white
  • Pectoral fin short, much shorter in length than head
  • Eyes relatively small (compared with Isurus paucus)
  • Anal-fin origin about level with midbase of second dorsal fin
  • Anterior teeth with smooth-edged cusps, curved in at bases but with tips reversed and curving outward

Colour:

Dorsal surfaces indigo blue (becoming grey after death), grading to lighter blue on the sides to white ventrally; undersurface of snout white.

Size:

Maximum size up to ~400 cm TL; size at birth size 60–70 cm TL

Distribution:

Circumglobal in all tropical and temperate seas (rarely found in water less than 16°C) from the surface to at least 650 meters depth.

View FAO distribution map.

Habitat:

A pelagic and mostly oceanic species, occasionally found around islands and close to land.

Biology:

Feeds primarily on cephalopods, turtles, porpoises, seabirds, smaller sharks and bony fish (e.g. mackerels, tunas and bonitos). Length at maturity is ~270 cm TL and ~195 cm TL for females and males respectively. Age at maturity is 18 years and 8 years for females and males respectively. Reproductive mode is viviparous with oophagy, gestation is possibly 15–18 months with a 3 year reproduction cycle. Litter size is 4–25 (usually 10–18, average 12) pups.

Indonesian fisheries:

Caught primarily by tuna and shark longline fisheries. Utilised for its high quality meat, fins (high value in adults), jaws (highly prized), skin and cartilage.

Similar species:

Isurus paucus
Isurus paucus
Isurus paucus differs in having a more pointed snout that is white ventrally (vs. less pointed snout that is dusky ventrally) and pectoral fins far shorter than length of head (vs. pectoral fins about as long as head).
Prionace glauca
Prionace glauca
Prionace glauca differs in having a asymmetrical caudal fin, with a much longer upper lobe and shorter lower lobe (vs. caudal fin lunate, with upper and lower lobes of similar length).

Internal links:

Isurus oxyrinchus interactive learning
Isurus oxyrinchus market gallery

External links:

FishBase
The IUCN Red List of Threatened SpeciesTM