Salmon Shark

About the Salmon Shark

The Salmon Shark is a coastal shark found in both nearshore and oceanic environments. They are commonly from near the surface to at least 152m (499 ft) deep. These sharks live in northern regions that have cool temperate waters, ranging from 5-18°C. They are native to the north and the central Pacific Ocean and are common in Canada, The United States, the Gulf of Alaska, Sea of Japan, as well as the California Current.

Biology:

Salmon Sharks have stocky bodies and a cone-shaped snout. They have relatively long gills and a broad and rounded mouth containing around 55 moderately large, blade-like teeth. Each tooth has two small hook-like teeth on each side called cusplets. They have a large first and much smaller second dorsal fin (top fin), a small bottom fin and a crescent-shaped fin in the tail. They’re commonly found alone or in schools and feeding clusters up to 30 to 40 sharks. Males are commonly estimated to reach sexual maturity at approximately 140 cm (55 in) and females between 175 cm (68.9 in). Salmon Sharks have a typical lifespan of 20 to 30 years. The max length of a Salmon Shark is 305 cm (120 in) while the common length is 180cm (70.9 in). They can also weigh upwards of 220 kg (485 lb). The Salmon Shark is one of only five shark species that is endothermic which mean they have warm blood. Their body temperatures can exceed water temperatures by as much as 21.2°C.

Reproduction:

Salmon shark eggs hatch within the body of the mother shark, with up to 4 young in a litter. The hatched young feeds on unhatched and unfertilized eggs. They are ovoviviparous, meaning it produces young by means of eggs that hatch inside the mother’s body.

Behaviour:

They are fast swimmers and are potentially dangerous but have rarely attacked humans, although damage to commercial gear has been reported. They eat smaller fish like mackerel, daggertooth fish, and salmon. Salmon sharks are season migrators and suspected to follow the movement of preferred prey, for instance, the western North Pacific population follows herring and sardines and the eastern North Pacific populations follows Pacific salmon species.

A remarkable sex ratio difference occurs in Salmon Sharks across the North Pacific areas. The male sharks dominate the western side and the eastern side is female dominated. Larger sharks range farther north than smaller individuals, with dominance increasing with latitude and southern catches generally occur in deeper waters.

Salmon Shark population appears to be stable.

It is caught as target and bycatch in coastal and pelagic commercial and small-scale longline, purse seine, and gillnet fisheries, and is often retained for its meat as well as fins. The population appeared to be stable at relatively high levels of abundance during the 1990s and early 2000s. Since cessation of an open ocean gillnet fishery in the early 1990s, the population may be rebuilding. There is no information available on population trends since that time, except an anecdotal note by recreational fishers of a decline in catch in Prince William Sound, Alaska that resulted in a self-imposed avoidance of this species. Other than this noted decline in Alaska, there is nothing to infer population decline and thus, the species is assessed as Least Concern. Improved catch monitoring, analysis of the population trend analysis, and precautionary fishing limits are recommended.

The species is used for its meat and fins (Goldman and Musick 2008, Fields et al. 2018, Cardeñosa et al. 2018). Together with the Porbeagle, the two species accounted for 0.2% of the fin imported in Hong Kong in 2014 (Fields et al. 2018).

The success of actions agreed through international wildlife and fisheries treaties depends on implementation at the domestic level; for sharks, such follow up actions have to date been seriously lacking.

Beyond finning bans, there are no international conservation commitments that are directly applicable to Salmon Sharks. In Canada, the species can only be retained by recreational fishers, with a bag limit of one Salmon Shark per day per recreational fisher. The U.S. includes the species under a general Total Allowable Catch for sharks taken as bycatch in North Pacific commercial groundfish fisheries. U.S. recreational fishing for Salmon Sharks has been managed through bag limits, etc. at the state level.

To ensure population health, it is recommended that Salmon Shark fishing be limited throughout their range, based on scientific advice and/or the precautionary approach. Improved reporting of catch and discard data, and promotion of safe release protocols are also advised.

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Salmon Shark Gallery