Prickly Shark - Biology and Ecology

Biology and Ecology

The prickly shark is a slow swimmer and has been observed hovering just above the sea floor. A tracking study in Monterey Canyon found that this species exhibits strong diel migration patterns. The sharks were inactive during the day, resting in discrete refuge areas located near the sea floor in deep, offshore waters. They became active at dusk, swimming towards the coast to the head of the canyon and rising into the water column; this upward movement is likely related to feeding on schooling fishes. Individual sharks seldom strayed from the local area and had very small home ranges, no more than 2.2 km2 (0.85 sq mi). The prickly sharks in Monterey Canyon regularly form aggregations that may number over thirty.

The size and structure of the prickly shark's mouth and pharynx suggests that it uses suction to capture prey. This species feeds on a variety of benthic and pelagic bony fishes, including hake, flounders, rockfishes, lingcod, topsmelt, mackerel, and herring, and on cartilaginous fishes, including elephantfishes (Callorhinchus), spiny dogfish (Squalus acanthias), young bluntnose sixgill sharks (Hexanchus griseus), and ghost catshark (Apristurus) egg cases. Octopuses and squid, including the Humboldt squid (Dosidicus gigas) are also consumed. Young prickly sharks may themselves fall prey to the bluntnose sixgill shark, while adults likely face few threats. Reproduction in this species is aplacental viviparous, with the unborn young sustained by yolk. There is only one known record of a pregnant female, which was gestating 114 embryos; this ranks among the largest known litters from any shark. The young are probably under 40 cm (16 in) long at birth. The length at sexual maturity has not been precisely determined but is thought to be around 2.0 m (6.6 ft) for males and 2.5–3.0 m (8.2–9.8 ft) for females.