Tope Shark: Galeorhinus galeus

Family: Triakidae
Common name(s)

Tope Shark, Soupfin Shark, School Shark.

Identification

Body fairly slender. Snout long and pointed. Upper labial furrows somewhat longer than lower. Small, visible spiracle behind eye. First dorsal fin origin posterior to pectoral fin free rear tip. Second dorsal fin origin opposite anal fin origin. Second dorsal fin small; same size as anal fin. Long, distinct, lower caudal lobe with a pointed tip. Very long terminal caudal lobe. Dorsal coloration grey-brown with bronzy hues. Fins somewhat dusky.

Size

Maximum length approximately 200cm. Size at birth 30-40cm.

Habitat

A cold/warm temperate species present in shallow bays, continental shelves, and upper slopes. Recorded down to 823m but generally in depths less than 200m; often from the surface to 40m.

Distribution

Widely distributed along most temperate coastlines but absent from the northwest Atlantic and northwest Pacific. On the west coast of North America, it is found from northern British Columbia to the end of the Baja Peninsula.

Conservation Status

CRITICALLY ENDANGERED

The tope shark has a particularly low biological productivity with a late age-at-maturity and triennial reproductive cycle. It is caught globally as target and bycatch in industrial and small-scale demersal and pelagic gillnet and longline fisheries, and to a lesser extent in trawl and hook-and-line fisheries. Tope is often retained for the meat and fins but is discarded or released in some areas, in line with regional management measures. Steep subpopulation and stock reductions of >80% over the past three generation lengths (79 years) have occurred in the Southwest Atlantic, southern Africa, and Australia. In the Northeast Atlantic, the subpopulation is estimated to have undergone a reduction of 76% over the past three generation lengths (79 years). The New Zealand stock is estimated to have undergone a reduction of 30–49% over the past three generation lengths (79 years). In the Northeast Pacific, a dramatic decline in the subpopulation occurred in the early 1940s, with no recovery until 1997–2004 when localized management led to a localized increase in abundance. The consistent steep subpopulation reductions across most of the analyzed subpopulations and stocks together with the lack of movement between the subpopulations are cause for serious concern. Management in Australia, probably aided by the immigration of large mature animals from New Zealand, appears to have stabilized that stock since 2000. The subpopulation in the Northeast Atlantic has been stable in recent years, possibly due to management measures, and there is some recovery in part of the Northeast Pacific. Release of this species is mandatory since 2011 off Canada. Release is mandatory in European Union waters for line-caught Tope. The global population is estimated to have undergone a reduction of 88% with the highest probability of >80% reduction over the last three generations (79 years) due to levels of exploitation, and Tope is assessed as CRITICALLY ENDANGERED.

Citations and References
Walker, T.I., Rigby, C.L., Pacoureau, N., Ellis, J., Kulka, D.W., Chiaramonte, G.E. & Herman, K. 2020. Galeorhinus galeusThe IUCN Red List of Threatened Species 2020: e.T39352A2907336. https://dx.doi.org/10.2305/IUCN.UK.2020-2.RLTS.T39352A2907336.en. Downloaded on 26 October 2020.

Reproduction

Aplacental viviparous (live-bearing without yolk-sac placenta). 6-52 pups per litter. Gestation is approximately 12 months. The soupfin shark is a late maturing species (females 11-17yrs, males 9-13yrs) with a very low productivity i.e. females become gravid every 3yrs and rest for 2yrs. These reproductive limitations combined with overfishing have caused extreme declines within this species.

Diet

An opportunistic feeder, Diet includes a wide variety of small bony fishes (e.g. sardines, flounders, midshipmen, rockfish, and mackerel) and invertebrates.

Behavior

Migrates to warmer water in the winter. Sometimes seen in mixed schools with other houndsharks such as leopard sharks.

Reaction to divers

Shy in non-baited situations. Intimidated by scuba bubbles. Sometimes makes close passes on snorkelers.

Diving logistics

Large schools of tope sharks pass through La Jolla (near San Diego) in mid to late summer. I encountered many in August while snorkeling over rocky terrain, under the bluffs to the south of La Jolla Shores. When migrating through the region, they may be common along the entire coastline but I entered at the Marine Room and did not encounter any until I swam beyond the open sand onto mixed rock and kelp. Unlike the leopard sharks that inhabit La Jolla and mostly predate on crustaceans, topes probably prefer rocky terrain where their preferred prey of bony fishes is more abundant.
Be warned that tope sharks pass through in waves, wherein they may be absent one day and abundant the next.

Similar species

Grey Smoothhound Shark In the Eastern Pacific, this species (and all other smoothhound shark species) may be confused with the tope shark but they are all easily distinguished by having a second dorsal fin that is much larger than the anal fin.