Silky shark

silky shark profile

Photograph by Andy Murch

View all available Silky Shark Pictures in the Shark Pictures Database

Common Names: Silky shark

Latin Name: Carcharhinus falciformis

Family: Carcharhinidae

Identification: Long pointed snout. Interdorsal ridge present. Low rounded first dorsal fin originates behind pectoral axis. Small second dorsal with long free rear tip. Pectoral fins long with dusky or black tips on underside. Second dorsal much smaller than first. Dorsal body coloration olive brown with distinctive reflective sheen that gives this shark its common name.

Size: Maximum length 3.3m. 70 to 87cm at birth.

Habitat: Prefers offshore islands, sea mounts, drop offs and vertical rocky or coral reefs. To 500m depth. One of three species (also including Oceanic Whitetip and Blue Shark) of sharks that patrols the open ocean.

Abundance and distribution: Circumtropical.

Behavior: Arching back threat display recorded.

Reproduction: Viviparous. Litter size 2 - 14.

Conservation Status: Listed as VULNERABLE by the IUCN. The Silky Shark is the second most caught species of shark globally, after the Blue Shark (Prionace glauca) (Oliver et al. 2015). The Silky Shark is both targeted or caught as incidental (bycatch) by longline fisheries and purse seine fisheries (especially those using drifting fish aggregating devices [FADs]) as well as by artisanal fisheries. FADs are made of a floating object and nets that lie vertical in the water column to attract schools of fish. The Silky Shark, as well as other species, is easily entangled in the nets; and there have been large increases in the use of FADs since 1996 (Leroy et al. 2013). Whether they are targeted or an incidental catch, the Silky Shark is often either retained for its meat and fins where regulations allow, or released with high mortality rates apparent in the tropical purse seine fisheries (Hutchinson et al. 2015). Total catches of the Silky Shark reported to FAO are mainly from Sri Lanka (Western Indian Ocean) with the FAO catch less than 4,000 tonnes (t) from 2005-2009 before doubling in 2010 and 2011. Catches then decreased to ~5,000 t in 2012 and 2013 (FAO 2015).
The Silky Shark was found to represent at least 3-4% of the fins auctioned in Hong Kong, the world's largest shark fin trading centrethe third highest after Blue Shark and Hammerhead Shark (general) (Clarke et al. 2006a)and Hong Kong is thought to make up more than half of the global shark fin trade (Clarke et al. 2004, 2006b). Silky Shark fins are valuable to the trade, although they are not one of the highest value fin types (S. Clarke, unpubl. data).

Photographs: Top - Cat Island, Bahamas. Bottom - Galveston, Texas.

Similar species: Although the silky shark is superficially similar to many other carcharinid species, it is easily recognizable by its shiny skin and low rounded first dorsal. Some older silky sharks may lose their lustre. At that point they may be confused with other species e.g. dusky sharks Carcharhinus obscurus. Duskies have a higher, more pointed first dorsal and a slightly blunter snout.

Reaction to divers: Reactions vary depending on size, location, and style of interaction. In Galveston, Texas the silky sharks tend to be small and hard to approach. At Cat Island in the Bahamas, they are more used to divers and allow a close approach. At offshore islands in the Eastern Pacific such as at Cocos Island in Costa Rica, there are so many large and aggressive silkies that at times it is not safe to enter the water as they may bump and possibly bite divers. At Cat Island in the Bahamas the silkies are becoming used to divers and freely swim around them.

Diving logistics: Silky sharks are common at nurmerous locations around the world. Around the Eastern Pacific islands such as Socorro and Cocos, they can be seen feeding on baitfish on offshore seamounts.

During oceanic whitetip shark dives at Cat Island in the Bahamas, silkies allow divers to approach within touching distance. Big Fish Expeditions runs shark diving trips to Cat Island every April.

Jardin de la Reina in Cuba is another reputedly good place to find them.

Citations:

Rigby, C.L., Sherman, C.S., Chin, A. & Simpfendorfer, C. 2017. Carcharhinus falciformis. The IUCN Red List of Threatened Species 2017: e.T39370A117721799. http://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T39370A117721799.en. Downloaded on 01 January 2018.

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SILKY SHARK