Blacktip reef shark (Carcharhinus melanopterus) is an ocean shark popular with many common names such as black-finned shark, blackfin reef shark, gunman, blacktip shark, and reef blacktip shark.
As you may have guessed, this awesome fish got its name from the striking black tips on its fins and its pointed snout. It belongs to the requiem shark species (lemon, tiger, and bull sharks) and of the family of Carcharhinidae.
Blacktip reef shark has a common habitat of shallow, warm water around coral reefs in the Mediterranean Sea and indo-pacific at depth up to about 262 feet. To shark keepers and enthusiasts, this is one of the Most Lovely sharks in the ocean.
Behavior/Disposition
Blacktip reef sharks will mostly swim in shallow waters with their dorsal fin tips displaying at the surface. These sharks are timid and shy towards other predators when alone. Therefore, they prefer to stay in larger groups, thus making scientists conclude that their philosophy is in the power of numbers.
As a result, Black-finned sharks are very social fish, typically found in larger groups and have a strong hierarchy. More so, they are a bit of a curious fish shown in their interactions with divers when they enter the water. Although, they tend to get swept off due to their timid demeanor.
Blacktip reef fish are quite aggressive when around speared fish. And, their aggression can become worse when they are around a competing shark.
These incredible sharks display a behavior called “Breaching” which is an ability to fully jump out of the water and back in. Also, they engage actively in “Spy-hopping” which is an ability to surface and look around.
Communication
Blacktip sharks are curious sharks and would often use senses of sight, hearing, electro-perception, and smell, to communicate, to share food or defend themselves. For instance, they open their mouth while arching their body to display a threat to other sharks.
Also, they show their swimming techniques like turning away to dominate their space in the water. More so, Blacktip sharks can pass a message by using their tails to slap the water. This action serves as a form of discouragement to other sharks that are meddling with their prey.
Geographical Distribution
The Blacktip reef sharks occur in the Indian Ocean and Western Pacific
These sharks are mostly found in tropical Indo-pacific. Thus, Reef Blacktip Sharks’ distribution range includes waters surrounding China, the Philippines, Thailand, Malaysia, Indonesia, New Caledonia, Papua New Guinea, Northern Australia, and Japan.
Blacktip reef shark exists also in Mauritius, South Africa, Madagascar, Seychelles, Pakistan, the red sea, Sri Lanka, India, and the Maldives
Blacktip reef shark habitat
These sharks usually prefer clear, shallow waters. As a result, Blacktip reef sharks habit around coral reefs and sometimes in brackish water conditions.
When in juveniles, they will mostly habit the highly shallow water in lagoons; mostly swimming by the shoreline. However, as adults, Blacktip reef shark generally come about in shallow areas of forereef going over the reef to the flat reef at the tide of the flood.
Most adults individually dwell in a home of 2.5square km range and they stay close to their home reef. Sometimes, they cross deep water lines between adjacent reefs.
Blacktip reef sharks are tropical fish with a preferred water temperature of about 59°F (15 °C) to 75.2°F (24 °C). They are also present in the Red sea of Indo-pacific to the Tuamotu Archipelago.
Blacktip reef sharks are one of the most common reef sharks. Though, there are two others in Indo-pacific, whitetip reef shark and grey reef shark.
Can blacktip reef shark be kept in Home Aquarium as Pet?
No, blacktip reef shark cannot be kept as a pet. This is because they grow too big for any home aquarium. And, keeping them and taking care of them is very expensive. Moreover, it is illegal to keep sharks as a pet in many countries to think of owning a Blacktip reef shark as a pet.
What is the Blacktip reef shark scientific name?
Although, they have many common names; their scientific name is “Carcharhinus melanopterus”
Mating/ Reproduction
Blacktip reef shark like its other family members is viviparous. As such, they do not lay eggs and give birth to their young ones alive.
Cycle
Their reproduction cycle is annually off northern Australia and their mating occurs from January to February. Although, in Moorea French Polynesia, their mating takes place between November to March.
Blacktip reef shark cycle may occur Biennially when intense competition among species for food, constrains their females to only bearing young ones every other year. The history of blacktip reef shark by Johnson (1978) showed a biannual cycle in the region with two breeding in a season every year from December to January and June to July.
Courting
Black-finned shark when receptive to mating swims in a sinusoidal pattern slowly by the bottom with its head pointing down. On the same note, observation in the wild indicates that female blacktip reef shark discharge signals of chemicals that allow the male to be able to track it.
Once the male can track the female, He stays around 6 inches (15 cm) close and follows her with his snout pointed at her vent. More so, a male that is courting might also bite the female it is courting on her pectoral fins. Sometimes, the injury sustained from this bite may take about 4 to 6 weeks to heal completely.
After the period of swimming synchronously, the male black-finned shark pushes the female its courting so she is on her side. At this point, her head would be in a position where it is against the bottom, while it raises its tail.
Sexing
The male then inserts one of its claspers into the female cloaca. Black-finned sharks mate by facing each other because their sex organs are on their underside.
Copulation lasts for about 5 to 6 minutes and then they separate and resume their normal behavior.
In Moorea, most individual older females mate and reproduce at a consistent time every year whereas the younger ones exhibit variability in their mating. Moreover, the younger females are liable to fail in getting pregnant after the first mating.
Gestation
Their gestation period reportedly lasts for 10 to 11 months in the pacific islands and the Indian Ocean. Also, it may last about 7 to 9 months as in northern Australia.
Black-finned sharks female have one functional ovary and two functional uteri that have divisions into different compartments for a single embryo. On the same note, eggs newly ovulated measures up to 1.5in (3.9 cm) by 1.0 in (2.6 cm).
After hatching, the embryos are held by a yolk sac during the early first stage of development. And after two months, the embryo has well-developed external gills. When the embryos reach about 5months the placenta and external gills are fully formed.
Young black-finned sharks will usually form large groups in a water body that is hardly deep enough to cover their entire body. The males and females of blacktip reef shark mature sexually at a length of 94 – 97 cm severally off in northern Australia and about 104 – 110 cm in Aldabra.
Blacktip reef sharks when in juveniles are self-sufficient and do not receive any care from their parents. A research in 2008 with DNA evidence discovered that females of blacktip reef shark can reproduce asexually. That is, in a situation where the males are not available.
How to Identify a Blacktip Reef Shark
Black-finned sharks are moderate in size with a typical shark form. Thus, they have a short, dull, rounded snout, and black and white color on the tip of the first dorsal fin and the lower caudal fin.
Black-finned sharks have a fairly moderate large oval eyes. And, their nostrils have a flap of skin in front of each that expands into nipple-like shape. These shark species have tooth rows of about 11 – 13 on each side of their upper jaw and about 10 – 12 on each side on their lower jaw.
They have narrow and erect teeth on their upper jaw with cusps and coarse serrations. Meanwhile, their lower jaw teeth appear raised, but oblique with narrow serrated cusps.
These reef sharks are usually grayish-brown shade, a color that helps them camouflage when hunting or hiding from predators. Their pectoral fins generally have the shape of a sickle.
Their first dorsal fin is tall and the ventral caudal has an obvious black blotch, perfectly traced with white. All their fins are highlighted by lighter colored borders with a black tip which is quite obvious on the first and the lower caudal fin.
More so, their caudal fin appears crooked with an extended top lobe. Most of their other fins usually have black tips with a conspicuous white band on the flank.
Black-finned sharks have denticles. That is placoid scales that are tooth-like in shape and held firmly in the skin.
Blacktip Reef Shark Size
These beautiful sharks can grow up to about 6 feet (2 m) long. More so, Blacktip reef shark has a record with a maximum weight of 30 Ibs (13.6kg).
The growth rate of the blacktip shark is rapid. These sharks have regional variations in their size at birth, maturity and max size. As a result, a documented shark held in captive recorded a 9 inches (23cm) growth rate in a space of two years.
They usually grow to about 5.2ft maximum. However, there is a record of a Blacktip shark at 5.9ft growth length.
Blacktip reef shark is usually born with a size ranging from 1.2 ft to 1.4ft. Their males mature at 3 – 3.3ft and their females at 3.1 – 3.7ft.
Feeding/Hunting
Blacktip sharks diet compose majorly of small teleost fishes such as groupers, jacks, grunters, mojarras, surgeonfish, wrasses, smelt-whitings. They also consume octopus, squid, cuttlefish, mantis shrimp and carrion.
These species of sharks are also popular for eating up sea snakes such as Hydrelaps Darwiniesis, Lapemis Hardwickii, Hydrophis, Acrochordus Granulatus.
Sharks like blacktip reef shark merge physical adaptations like heightened senses, sharp teeth, a big body and tail with their behavioral techniques to catch their Preys. As such, they rotate their bodies several times, leap above the water surface to strike at prey such as a school of bony fish.
Black-finned sharks are nocturnal predators by nature and would often feed at night within low and high tides especially in shallow waters. Of course, most sharks have their method of hunting their Preys. As a result, blacktip reef sharks make use of their body weight, speed and the force of their teeth to assault their Preys. They do not use much energy so they could retain some calories needed for migration.
Blacktip reef shark, unlike every other shark, does not have any cone cells in their retina which makes their ability to discriminate colors and fine lines limited. However, they can easily detect movement or contrast in low light conditions.
Also, by using electroreception; blacktip sharks can locate their prey. Research shows that blacktip reef shark can detect objects as little as 1.5 – 3 meters away. Although, they cannot discern the shape of the object.
Note
These species have something in common with a grey reef shark. Thus, they get excited in the presence of other species and sometimes go into a feeding frenzy.
Researchers discovered that blacktip sharks can be attracted by striking metal tools on hard objects in the water or by splashing water. Also, by the smell of both injured and healthy fish.
Migration
Most sharks migrate every season to mate in their breeding grounds and give birth in nurseries. Usually, they use electroreception to survive and to birth pups.
Blacktip reef shark gives birth to their pups throughout late spring and summer. Afterward, they stay in their nurseries for protection from predators until they migrate south during the winter.
IUCN Red List Status
On the IUCN (International Union for Conservation of Nature) Red List, Blacktip Reef sharks appeared as “Near Threatened (NT)“.
Status of Population
Blacktip reef shark is not endangered currently and still have higher numbers in the wild than most shark species today. However, these species are experiencing loss in population due to overfishing (mostly used in making shark fin soup) and slow reproduction in this species.
Also, because of their preference for shallow waters which makes them vulnerable to coastal development including Commercial fishing, and nursery sites that are common in India, Mexico, and the Southeastern United States. All contribute to the threat in the existence of Blacktip sharks.
History of Blacktip reef sharks
Sharks generally have a long history of fossil, dating back to about 450 million years ago.
Domestication of sharks
Humans have not been able to domesticate any species of shark
Blacktip reef shark Care in a Zoological Setting
In a zoological environment, black-finned sharks thrive well. Thus, they are housed in a huge aquarium with other sharks and different fishes. Aquariums make it easy for them to reproduce.
Blacktip reef sharks entertain guests with their shark-like behavior when in the aquarium. Most of the blacktip shark lives up to about 13 years of age or more. Also, it is easy for the aquarist to feed black-finned sharks in the aquarium, since they are carnivorous and eat virtually anything that has blood you put in the aquarium.
Ecology and Biology
There are three types of reef sharks, but the most common one is the blacktip reef shark in the Indo-pacific.
Blacktip reef shark spends most of its time swimming back and forth near the ledge. More so, they have a decrease in swimming speed when the tide rises in the night maybe because cooler water reduces their metabolism.
On the other hand, Blacktip reef sharks found in Aldabra are more mobile compared to those found in Palmyra. These sharks when in juvenile fall prey to larger fishes such as grey reef sharks, groupers and tiger sharks. They have a known parasite that includes tapeworms ( Nybelinia Queenslanders, anthobothruim, platybothrium).
Phylogeny
The phylogenetic position of this shark is still indeterminate. On Morphology, Jack Garrick offered in 1982 that the closest to black-finned shark was a nervous shark (C. cautious). A popular scientist Leonard Compagno in 1988 morphological analysis indicated affinity with a nervous shark.
Territorial Nature
Blacktip reef shark of different sizes, when in juveniles will bite and eat one another when they are very hungry, but can live together.
Difference between Blacktip reef shark and Other Reef sharks
Most times, the blacktip reef shark is often confused with other reef sharks because of their similarities. However, the difference between the grey reef shark and the blacktip reef shark is the absence of black tips on its dorsal fin. More so, grey reef shark possesses a stockier body. The apparent black tips on all grey shark fins may get people easily confused.
Whitetip shark is a bit smaller than other reef sharks and has a short head and flattened snout compared to blacktip reef sharks. Also, from their name; the tip of their first dorsal fin is in white color. They are also different in that they can pump water over their gills to breathe, unlike the blacktip reef shark that has to keep swimming to breathe.
Threat to Humans
Blacktip reef sharks seldom pose any threat to humans. Even more, they are timid and get easily frightened by swimmers.
Blacktip reef sharks are one of the common species of sharks that comes in contact with humans in the Indo-pacific. The International Shark Attack File (ISAF) has no record on death files from them. And, has so far only recorded 11 unprovoked attacks on humans.
Most attacks recorded since 1959 till present is of blacktip shark biting the feet or legs of waders, obviously mistaken it for prey. However, the same cannot be said of humans, as they have constantly hunted these sharks for their fins, meat, and oils from their livers. In all, Blacktip reef sharks do not have much commercial value.
Blacktip Reef Shark Interesting Facts
- Reef Blacktip shark can reach up to about 8ft in length and 65 to 200 pounds in weight. Most times, males are bigger than females
- The snout of blacktip reef shark is blunt and they have almond-shaped eyes.
- Black-finned sharks have grayish-brown or bluish grey and a white line on the lateral side of their body.
- Although blacktip reef shark is popular because of the blacktip on their dorsal fin, all of their fins still end with a specific triangle mark.
- Blacktip reef sharks are mostly found in the shallow water of about 12 inches deep. And, barely covering their whole body.
- Unlike whitetip sharks that can pump water in their gills to keep breathing, blacktip reef shark needs to stay swimming to stay alive and not suffocate since water only enters their gills when they swim.
- Also, these sharks do not have a swim bladder. Thus, to remain afloat and not sink, they need to keep swimming.
- Blacktip reef sharks are known to follow fishing boats. So, they could eat discarded fishes and other creatures in the sea.
- Blacktip reef sharks can live up to 12 years in the wild or more.
- Their mating season depends on their geographical location, but most of them give birth during winter and spring and their pregnancy lasts up to about 16 months with 2- 4 pups at the end.
- Blacktip reef shark can leap out of the water and spin in the air. Behavior associated with catching fishes that swim on the surface of the water.
More Facts
- Blacktip reef sharks are not aggressive towards humans.
- Reef blacktip sharks have black tips on every one of their fins except anal fin that is taped with white.
- The biggest black-finned shark recorded was a female shark that measured up to 6.8 feet long.
- The oldest blacktip reef shark was 15.5 years old.
- Reef black-tipped shark can smell and detect a part of fish flesh in 10 Billion parts in seawater.
Superstitions about sharks
A lot of people fear sharks as a whole, which is not meant to be. Sharks are not demons contrary to popular opinion. certainly, the species of sharks recorded to have attacked humans without being provoked have most times misidentified humans as prey.
Diseases
Blacktip reef sharks are susceptible to crytocaryon and fluke when stressed in a public aquarium. These infections can be treated by organo-phosphates like Neguvon, dylox, masoten, Trichlor and DTP.
Importance of blacktip reef sharks to Humans
Inshore fisheries mostly catch these fishes in some parts of their distribution. As such, they are most important for meat, liver oil and fins extraction. Blacktip reef shark is also important in dive tourism and aquaria.
Conclusion
As you have read in this article, Blacktip reef sharks are not Home aquarium sharks. Therefore, do not try to keep them as one even if you find your means.
They are ocean sharks that may only thrive in public aquariums and their natural habitat.
The aim of this page is to describe the Blacktip Reef Shark and state the amazing facts about them. As such, you may know the reason for the popularity of these amazing creatures. However, if you need to know more you can follow the reference link below for further reading!
References
http://www.wetwebmedia.com/blacktipshark.html
https://en.m.wikipedia.org/wiki/Blacktip_reef_shark
https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/carcharhinus-melanopterus/
https://www.thainationalparks.com/species/blacktip-reef-shark
http://www.softschools.com/facts/animals/black_tip_shark_facts/546/
https://sciencing.com/behavioral-adaptations-sharks-8591999.html