page_title: Sharptooth houndshark
section_title: Biology and ecology
hierarchical_section_title: Sharptooth houndshark / Biology and ecology
caption_attribution_description: English: Plagusia chabrus
context_page_description: The sharptooth houndshark, or spotted gully shark is a species of houndshark in the family Triakidae found in shallow inshore waters from southern Angola to South Africa. Favoring sandy areas near rocky reefs and gullies, it is an active-swimming species that usually stays close to the bottom. This robust shark reaches 1.7 m in length and has characteristically large, rounded fins; the pectoral fins in particular are broad and sickle-shaped in adults. It also has a short, blunt snout and long furrows around its mouth. This species is gray or bronze in color above, with variable amounts of black spotting.
  Mainly active at night, the sharptooth houndshark feeds mostly on crustaceans, bony fishes, and cephalopods. It has been observed gathering in groups in shallow water during summertime, possibly for reproductive purposes. This species is aplacental viviparous, meaning that the unborn young are sustained mainly by yolk. Females give birth to 6–12 pups between late May and August, on a 2- or 3-year cycle. The sharptooth houndshark is often hooked by recreational anglers, and some are also captured on commercial bottom longlines.
context_section_description: The sharptooth houndshark is a highly active species, though it can sometimes be found resting inside rocky crevices. It mainly hunts at night and has been known to pursue prey almost onto the shore. The pointed cusps of its teeth allow it to grasp slippery prey, while their broad bases allow it to crush hard-shelled prey. This shark feeds on a variety of crustaceans (crabs, slipper lobsters, and spiny lobsters), bony fishes (including morwongs, sea catfishes, drums, and porgies), and cephalopods (in particular Octopus vulgaris). Sharks and rays (including catsharks and guitarfishes) and their egg capsules are a minor food source for larger individuals. Off South Africa, the most important prey species is the crab Plagusia chabrus. Its dietary composition changes with age; young sharks under 1.0 m (3.3 ft) long subsist almost completely on crabs, while larger sharks consume more bony fishes and cephalopods, as well as a greater variety of prey overall. This shark has been observed deviating from its nocturnal habits to feed on chokka squid (Loligo reynaudii) during their mass spawnings. The broadnose sevengill shark (Notorynchus cepedianus) is known to prey on this species.
  During the summer, the sharptooth houndshark forms groups in shallow water. These aggregations are particularly well-documented in False Bay and may be related to reproduction, given the presence of many pregnant females. It is aplacental viviparous, with the developing embryos nourished mainly by yolk. Mature females have a single functional ovary and two functional uteri. Litters of 6–12 pups are birthed between late May and August, following a gestation period of some 20 months. Larger females tend to produce larger litters. The length at birth has been variously estimated as 30–32 cm (12–13 in) and 42–44 cm (17–17 in) by different sources; pups within a single litter may vary in size by up to 30%. Females apparently reproduce either every two or three years, depending on whether she has ovarian eggs developing during the pregnancy that would allow her to mate again within a few months of giving birth. The sharptooth houndshark is a slow-growing species, with both sexes following a similar growth pattern. Males mature sexually at 1.2–1.4 m (3.9–4.6 ft) long and 11–13 years of age, while females mature sexually at 1.3–1.5 m (4.3–4.9 ft) long and 15–16 years of age. The maximum lifespan is at least 25 years.
caption: The crab Plagusia chabrus is the most important food source for sharptooth houndsharks off South Africa.
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