Author: (Günther, 1870)
Field Marks:
A large, often bronzy grey shark with a moderately long narrowly rounded or pointed snout, narrow and bent-cusped serrated anterolateral teeth without cusplets in the upper jaw usually 15 to 16/15 rows of anteroposterior teeth, usually no interdorsal ridge, long pectoral fins, a small first dorsal with a short rear tip and a small second dorsal with a short rear tip, and no conspicuous markings on the fins.
Diagnostic Features:
A large, fairly slender species (up to about 2.9 m). Snout moderately long and narrowly rounded or pointed; internarial width 1.1 to 1.4 times in preoral length; eyes circular and moderately large, their length 1.1 to Z.20/o of total length; anterior nasal flaps low and poorly developed; upper labial furrows short and inconspicuous; hyomandibular line of pores just behind mouth corners not conspicuously enlarged; gill slits moderately long, the third 2.5 to 4.1% of total length and less than a half of first dorsal base; usually 15 to 16/15 rows of anteroposterior teeth in each jaw half but varying from 14 to 16/14 to 15; upper teeth with narrow, strongly serrated, semierect to oblique, high bent cusps, and crown feet with slightly coarser serrations but no cusplets; lower teeth with semierect, narrow serrated cusps and transverse roots. Usually no interdorsal ridge. First dorsal fin large and falcate, with pointed or narrowly rounded apex and posterior margin curving ventrally or posteroventrally from fin apex; origin of first dorsal fin over or slightly anterior to pectoral rear tips; inner margin of first dorsal moderately long, a third of dorsal base or less; second dorsal fin small and fairly low, its height 1.9 to 2.6% of total length, its inner margin short and 1.2 to 1.8 times its height; origin of second dorsal over or slightly posterior to anal origin; pectoral fins moderately large, falcate, with narrowly rounded or pointed apices, length of anterior margins about 16 to 21% of total length; 179 to 203 total vertebral centra, 96 to 110 precaudal centra. Colour bronzy to olive grey above, white below; most fins with inconspicuous darker edges and dusky to black tips, but fin markings not conspicuous; a moderately prominent white band on flank.
Geographical Distribution:
Western Atlantic: Mexico, Gulf of Mexico, southern Brazil to Argentina. Eastern Atlantic: Mediterranean Sea, off France and Algeria, Morocco, Mauritania, Canary Islands, Guinea, Namibia to South Africa. Western Indian Ocean: South Africa. Western Pacific: Japan, the Koreas, China, southern Siberia; Australia (Queensland, New South Wales, Western Australia), New Zealand. Eastern Pacific: Southern California to Gulf of California; Peru.
Habitat and Biology:
An inshore to. offshore, warm-temperate shark, occurring from the surfline to at least 100 m depth. An active species, very common but with its hininnv nnnriv knnwn hacause of confusion with other species. Apparently migratory in the northern parts of its range, moving northward in the spring and summetime and southward in autumn and winter.
Viviparous, with a yolk-sac placenta; number of young per litter 13 to 20. Sex ration 1:1 at birth. Off South Africa sexual maturity is said to occur at about 5 years old, with a maximum age of at least 12 years.
Eats a variety of bony fishes, including sardines, sea catfish, mullets, jacks, porgies, gurnards, hake, and sole, as well as spiny dogfish (Squalus), torpedo rays, sawfish, squid and cuttlefish. Off South Africa large numbers of these sharks follow sardine shoals along the southern Natal coast in winter. Considered a dangerous species, with a few provoked and unprovoked attacks on swimmers and divers ascribed to it; it is probably much less dangerous than the tiger and bull sharks because of its slender teeth and feeding habits.
Size:
Maximum 292 cm, males maturing at 200 to 229 cm and reaching 266 cm, females maturing below 240 cm and reaching 292 cm; size at birth 59 to 67 cm.
Interest to Fisheries:
Little is recorded on the use of this species but it is undoubtedly caught and used for human consumption where it occurs. It is taken in bottom trawls, by line gear, and by sports anglers.
Remarks:
Important vernacular names include 'bronze whaler' (Australia) and 'narrowtooth shark' (United States; Robins et aL, 1980).
Type material:
Neotype: National Museum of New Zealand, NMNZ 2262, 2420 mm female, Wanganui, New Zealand, designated by Garrick (1982:174). New Zealand type material of C. brachyurus in British Museum (Natural History) are apparently lost, and two Australian fetuses referred to the species by Günther (1870) are C. leucas (Garrick, 1982). Type Locality: New Zealand.