Silky (Carcharhinus falciformis)

Silky (Carcharhinus falciformis)
According to the IUCN Red List of Threatened Species, the silky shark (Carcharhinus falciformis) is
Near Threatened globally. In a 2008 ecological risk assessment, the International Commission for
the Conservation of Atlantic Tunas (ICCAT) placed silky sharks at the highest risk levels of
overexploitation from pelagic longline fisheries. 1 Total global catch of this species reported to the
FAO has decreased steadily since 2000; from 11,680 tons reported in 2000 to 4,358 in 2004. 2 A
2005 study estimated that the silky shark population in the tropical central Pacific had declined in
abundance by about 90 percent between the 1950s and the 1990s. 3 In the Maldives, it is estimated
that this species represented close to 85 percent of oceanic shark catch. 4
Due to of their high rate of capture, silky
shark populations appear to be declining
across their range in the eastern and
western Pacific, the northwest and western
Atlantic, and the Indian Ocean. 5 In the
eastern Pacific Ocean, silky sharks are the
species most commonly caught as bycatch
in oceanic purse seine fisheries, which
often use drifting fish aggregating devices
(FADs) to target tuna, swordfish, and other
billfish.
Photo: Andy Murch / OceanwideImages.com
MAJOR THREATS
In 2002, longline vessels operating in the eastern central Pacific landed and exported over 8,000
tons of shark carcasses and 900 tons of shark fins from Costa Rica alone. 6 A majority of these
exports were recorded as silky sharks, though these figures most likely underestimate the true
catch rates, as many landings occur at private docks where enforcement and monitoring is difficult.
Additionally, fishermen often refer to silky sharks by the common Spanish name “punta negra,”
which has led to the common misclassification of silky sharks as blacktips.
IUCN Red List status: Near Threatened
Population Trend: Decreasing
Age of maturity: 5-10 years (males), 6-12 years (females) 7,89
Gestation period: 12 months 10
Litter Size: 2-15 pups 11
Life span: 22 years 12
A 2006 study found that silky shark fins were the third most commonly sold fin species in Hong
Kong, the world’s largest shark fin trading center, following blue sharks (Prionace glauca) and

scalloped hammerheads (Sphyrna lewini). 13 Between half a million and one and a half million silky
sharks are traded annually for their fins. 14 In addition to the value of their fins, silky sharks are
valued for their meat which can be prepared for human consumption, their skin for leather, and
their livers for oil. 15
GEOGRAPHIC DISTRIBUTION
Silky sharks are found in all
tropical waters around the
globe. They are pelagic (open
ocean) sharks and are most
commonly found near the
edge of continental and
insular shelves at depths of
200 meters (656 feet) or
more, but have been known
occur to depths of at least 500 meters (1,640 feet) further offshore.
Map: IUCN
Young silky sharks are often found in coastal nurseries. As sub-adults these sharks move further
offshore over deeper waters, frequently joining schools of tuna they seem to feed upon. 16 Silky
sharks feed on sea catfish, mullets, mackerel, yellowfin tuna, albacore, porcupine fish, as well as on
a variety of other fish species and cephalopods. 17,18
The primary source is the IUCN Red List Assessment
RBonfil et al., “Carcharhinus falciformis,” 2007, In IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4.
1 C. Simpfendorfer et al., “An integrated approach to determining the risk of over-exploitation for data-poor pelagic Atlantic sharks,” Expert
Working Group Report, ICCAT, 2008.
2 J.J. Maguire et al., “The state of world highly migratory, straddling and other high seas fisheries resources and associated species,” Fisheries
Technical Report no. 495. FAO, Rome, 2006, 67 p.
3 P. Ward and R.A. Myers, “Shifts in open ocean fish communities coinciding with the commencement of commercial fishing,” Ecology, 86(4),
2005, p. 835-847.
4 R. Bonfil et al., 2007.
5 R. Bonfil et al., 2007.
6 Costa Rica official INCOPESCA Fishery Statistics, 2003.
7 S. Branstetter, “Age, growth and reproductive biology of the silky shark, Carcharhinus falciformis, and the scalloped hammerhead, Sphyrna
lewini, from the northwestern Gulf of Mexico,” Environmental Biology of Fishes, 19, 1987, p. 161-173.
8 R. Bonfil, R. Mena, and D. de Anda, “Biological Parameters of Commercially Exploited Silky Sharks, Carcharhinus falciformis, from the
Campeche Bank, México,” NOAA Technical Report NMFS, 1993.
9 S. Oshitani, H. Nakano, and S. Tanaka, “Age and growth of the silky shark Carcharhinus falciformis from the Pacific Ocean,” Fisheries Science,
69(3), 2003, p. 456-464.
10 R. Bonfil et al., 1993.
11 P.R. Last and J.D. Stevens, Sharks and Rays of Australia, CSIRO Publishing, Australia, 2009.
12 Ibid.
13 S.C. Clarke et al., “Global estimates of shark catches using trade records from commercial markets,” Ecology Letters, 9, 2006, p. 1115-1126.
14 R. Bonfil et al., 2007.
15 L.J.V. Compagno, “FAO Species Catalogue. Vol.4: Sharks of the world. An annotated and illustrated catalogue of shark species known to date.
Part 2 - Carcharhiniformes.” FAO Fish. Synop. 125(4/2), 1984, p. 251-655.
16 R. Bonfil, "The Biology and Ecology of the Silky Shark, Carcharhinus falciformis." In Camhi, M., Pikitch, E.K. and Babcock, E.A., Sharks of the
Open Ocean: Biology, Fisheries and Conservation, Blackwell Science, 2008, pp. 114–127.
16 S. Branstetter, 1987.
17 L.J.V. Compagno, 1984.
18 R. Bonfil, “Contribution to the fisheries biology of the silky shark Carcharhinus falciformis (Bibron 1839) from Yucatan, Mexico.” (M.Sc. Thesis.
University of Wales, 1990).