April Elasmobranch of the Month: Silky Shark
Updated: Jun 26, 2021
Author: Linda Weiss
Silky sharks are a relatively large species, with females averaging in length between 2.1-2.3 m (7-7.5 ft). and males averaging 1.9-2.2 m (6-7 ft) The maximum recorded Silky measured 3.3 m (10.8 ft) long. Their body shape is slender with an interdorsal ridge and a fairly long, rounded snout and large eyes. Body coloration on the top and sides can be quite varied, from dark brown to bronze. Or blue-gray to gray. The underside is white. The first dorsal fin is relatively small and rounded. The second dorsal fin is small and has a long trailing tip that may nearly reach the caudal (tail) fin. The pectoral fins are relatively long. The caudal fin is forked with the upper lobe slightly longer than the lower lobe. The teeth in the upper jaw are broad and triangular in shape, with both sides heavily serrated. The teeth in the lower jaw are not serrated. They are smaller and pointed, with a more tack-like appearance. The dermal denticles, that make up shark skin, are small and densely packed on this species giving it a smoother, silkier feel, hence its name.
Silky Shark Image: Ambassador Michaela Palmer
Habitat and Distribution
This shark species can be found in the tropical and subtropical waters of the Atlantic, Pacific and Indian oceans. Juveniles typically spend their first few months near shallow reefs before moving out to deeper water. While largely a pelagic species, Silkies are also located inshore. Its depth ranges from 18 m (56 ft) - 4000 m (12,400 ft). Though it is most often found no deeper than around 500 m (1,640 ft).
The primary prey of the Silky is bony fish such as tuna, albacore, porcupine fish, mackerel and mullet. Their diet also includes squid, octopus, crabs and nautiluses.
The Silky shark’s gestation period is roughly 12 months. Reproduction occurs viviparously, where the young develop inside the female, receiving nourishment through a placental sac before being birthed alive. Pups are born is late spring in litter sizes typically ranging between 2-14 pups, that are 73-87 cm (2.5-2.10 ft) long.
The IUCN Red List of Threatened Species currently lists the Silky shark as Vulnerable, with a decreasing population trend.
The silky shark is targeted by commercial fisheries and is also caught during recreational fishing. This species is killed as bycatch of the swordfish and tuna fishing industries as well. Like many sharks, the Silky is targeted for its fins, oil and meat.
Shark Research Institute
The IUCN Red List of Threatened Species
Rigby, C.L., Sherman, C.S., Chin, A. & Simpfendorfer, C. 2017. Carcharhinus falciformis. The IUCN Red List of Threatened Species 2017: e.T39370A117721799. https://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T39370A117721799.en. Downloaded on 09 April 2021.