The tope shark is a large houndshark, and the only species in the genus Galeorhinus. It is found worldwide in temperate waters.
The tope shark is a widespread species, targeted by fisheries from the early 20th century. Populations seem to vary among regions, but no definite evidence have yet allowed to identify separate subpopulations.
Reproduction is through aplacental viviparity with litter size varying between less than 10 and more than 50 after a gestation period of approximately 12 months. The tope shark is long lived, up to 60 years and achieving sexual maturity around 10 years, which makes these populations susceptible to over exploitation.
The main threat to this species is fishing and like most elasmobranchs (cartilaginous fishes whoses skeleton is made of cartilage rather than bone), the tope shark is vulnerable to over exploitation due to its slow growth and low reproductive rate. This species is regularly taken as bycatch in demersal and pelagic fisheries. This species lives in age and sex segregated groups and this makes them particularly vulnerable as fishing can lead to skewed populations. Habitat degradation in coastal nursery sites due to human development and siltation may also be a threat, reducing the species ability to produce young. Installation of high voltage direct current cables under the sea may disturb tope shark migration routes with magnetic and electrical fields.
Although there are some conservation actions in place in Australia and New Zealand, such as limits on fishing equipment and fishing bans at nursery sites during birthing periods, there are few protection measures elsewhere in the world.
- Order: Carcharhiniformes
- Family: Triakidae
- Population: Unknown
- Trend: decreasing
- Size: Up to 193cm (?)
- Depth Range (m): Up to 400m
The tope shark is found worldwide in temperate waters, in the east and southwest Atlantic, the West Indian Ocean and the Pacific Ocean.
Habitat and Ecology
The tope shark is a strong active swimmer – able to swim 35 miles per day. It is also highly migratory. At higher latitudes it moves towards the poles in summer and towards the equator in winter and at lower latitudes it migrates between shallow waters during the summer and deeper waters during the winter. They show sex and size segregation and some site fidelity in estuary and shallower coastal habitats, apparently for pupping and nursery, where juveniles remain in the during the first two years of their life.
The tope shark’s diet consists mainly of bony fishes as it is mainly demersal in the continental shelf, although it roams into the pelagic zone.