The silky shark (Carcharhinus falciformis) is a large and slender shark that lives in tropical and warm temperate waters around the world. It is named for its smooth skin, which reduces drag and allows it to swim fast and agilely. It is one of the most abundant sharks in the pelagic zone, the open water away from the coast and the sea floor.

But what else do we know about this shark? In this article, we will explore some of the fascinating facts and features of the silky shark, as well as some of the latest news and updates on its conservation status.

How to Identify a Silky Shark

The silky shark has a streamlined body that can grow up to 3.3 meters (10 feet) in length but usually averages around 2.5 meters (8 feet). It has a long and pointed snout, large eyes, and a mouth with serrated teeth. It has two dorsal fins, the first one being relatively small and curved, and the second one being very tiny with a long free tip. It also has long and sickle-shaped pectoral fins, which help it steer and balance. Its color is metallic bronze-gray on the back and white on the belly, with no distinctive markings.

The silky shark can be distinguished from other large requiem sharks by its small first dorsal fin, tiny second dorsal fin, and long pectoral fins. It is often confused with the oceanic whitetip shark (Carcharhinus longimanus), which has similar coloration and body shape but has much larger and rounded dorsal and pectoral fins with white tips.

What Does a Silky Shark Eat?

The silky shark is a carnivorous predator that feeds mainly on bony fishes and cephalopods, such as squid and octopus. It has a keen sense of hearing, which allows it to detect the low-frequency sounds produced by other feeding animals, and by extension, sources of food. It often follows schools of tuna, a favorite prey, and sometimes cooperates with other sharks or dolphins to hunt. It can also drive its prey into compacted schools before launching open-mouthed, slashing attacks.

Where Does a Silky Shark Live?

The silky shark is highly mobile and migratory, that can travel long distances across the ocean. It is usually found over the edge of the continental shelf, down to depths of 50 meters (164 feet), but can also venture into deeper waters or closer to the coast, especially near remote islands such as the Galapagos Islands. It is mostly active during the day, but can also hunt at night. It is social and forms large aggregations, sometimes mixed with other shark species. It is not generally aggressive to humans but can become defensive if provoked or in the presence of food.

How Does a Silky Shark Reproduce?

The silky shark is viviparous, meaning that it gives birth to live young that are nourished by a placental connection to the mother. It reproduces year-round, except in the Gulf of Mexico, where it follows a seasonal cycle. The mating involves biting and nipping by the male, which can leave scars on the female. The gestation period lasts for about 12 months, and the litter size ranges from 2 to 16 pups, depending on the size of the mother. The pups are born at a length of about 80 centimeters (31 inches), and spend their first months in sheltered reef nurseries on the outer continental shelf, where they grow rapidly before moving into the open ocean. The silky shark reaches sexual maturity at a length of about 2.2 meters (7 feet) for females and 2 meters (6 feet) for males. The lifespan of the silky shark is estimated to be around 22 years.

Why Is a Silky Shark Vulnerable?

The silky shark is classified as Vulnerable by the International Union for Conservation of Nature (IUCN), meaning that it faces a high risk of extinction in the wild. The main threat to the silky shark is overfishing, both as a target and as a bycatch. The silky shark is valued for its meat, fins, skin, and liver oil, and is caught by various fishing gears, such as longlines, gillnets, purse seines, and trawls. It is also caught accidentally by fishermen targeting tuna and other pelagic fishes and is often discarded or retained as a bycatch. The silky shark has a low reproductive rate, which makes it vulnerable to overexploitation and population decline.

The silky shark is also threatened by habitat degradation, pollution, and climate change, which may affect its distribution, abundance, and food availability. The silky shark is protected by some national and regional regulations, such as size limits, catch quotas, and fishing bans. It is also listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which regulates international trade. However, these measures are often insufficient or poorly enforced, and the silky shark remains one of the most exploited sharks in the world.

What Are Some of the Latest News and Updates on the Silky Shark?

Despite the challenges and threats that the silky shark faces, some positive and hopeful stories show its resilience and adaptability. Here are some of the latest news and updates on the silky shark, as of January 12, 2024:

• In a shocking and rare case, a silky shark was observed to regenerate its dorsal fin less than a year after it was torn by humans. The shark was first photographed by an underwater photographer in July 2022, with a large wound in its dorsal fin, possibly caused by the removal of a satellite tag. The photographer then encountered the same shark again in June 2023 and was amazed to see that the shark had regrown most of its fin and was swimming normally. This is the first time that a silky shark has been documented to regrow its dorsal fin and the second recorded case of dorsal fin regeneration in sharks. The study, published in the Journal of Marine Sciences, suggests that the shark may have used new tissue, scar tissue, or wound border fusion to heal its fin, but the exact mechanism remains unknown.
• In a remarkable conservation effort, a team of scientists and divers from the University of Miami successfully tagged and released 10 silky sharks in the Galapagos Islands. The silky shark is one of the most abundant and iconic sharks in the Galapagos Marine Reserve, but its population has declined by 90% in the last 30 years due to fishing pressure. The tagging project, which was conducted in collaboration with the Galapagos National Park and the Charles Darwin Foundation, aims to track the movements and behavior of the silky sharks and to identify their critical habitats and migration routes. The data collected will help inform the management and protection of the silky shark and its ecosystem in the Galapagos and beyond.

Conclusion

The silky shark is a fascinating and important shark that plays a vital role in the pelagic ecosystem. It is a smooth and speedy predator that can hunt and travel across the ocean. It is also a resilient and adaptable shark that can recover from injuries and cope with changing environments. However, the silky shark is also a vulnerable and threatened shark that needs our attention and action. By learning more about the silky shark, and by supporting its conservation and research, we can help ensure its survival and well-being for the future.

Check out more articles!