The Pigeye shark or Java shark (Carcharhinus amboinensis) is an uncommon species of requiem shark, in the family Carcharhinidae, found in the warm coastal waters of the eastern Atlantic and western Indo-Pacific. It can be found in shallow, murky habitats with soft bottoms, and tends to roam within a fairly localized area. It looks almost identical to the Bull shark.
Family: Carcharhinidae – Requiem sharks
Common Name– Ground Sharks
Common Name– Requiem Sharks
Status: IUCN Red List DATA DEFICIENT
Average Size and Length: The Pigeye shark measures between 6.2 and 8.2 feet. The longest recorded shark was 9.2 feet long.
Average Weight: unknown
Teeth and Jaw: The mouth of a Pigeye shark produces a wide arch and has slight furrows at the corners. There are 11–13 (typically 12) upper and 10–12 (typically 11) lower tooth rows on each side. There are single rows of tiny teeth at the upper and lower symphyses. The teeth are broad and triangular with serrated edges. The ones in the lower jaw are slightly narrower, more upright, and more finely serrated than those in the upper jaw.
Head: A Pigeye sharks’ snout is short, broad, and rounded. The small and circular eyes have nictitating membranes. The anterior rims of the nostrils bear medium-sized flaps of skin.
Denticles: The Pigeye shark has larger dermal denticles, and as they age, the denticles become more tightly packed together. Each denticle has three to five horizontal ridges and five posterior teeth.
Tail: The Pigeye shark’s caudal peduncle has a deep notch on its upper surface at the caudal fin origin. The caudal fin is asymmetrical, with a well-developed lower lobe and a longer upper lobe with a notch in the trailing margin near the tip.
Demographic, Distribution, Habitat, Environment and Range: The Pigeye shark lives in coastal waters down to a depth of 490 feet. It prefers environments with fine sediment and murky water. It sometimes enters estuaries, but unlike the bull shark, it does not venture into rivers and it avoids brackish water.
The Pigeye shark is a rare and uncommon shark. Even though it is rare, it is widely distributed in the tropical and subtropical waters of Eurasia, Africa, and Oceania. Existing records are patchy, and the full extent of its range may be obscured by confusion with the Bull shark. In the eastern Atlantic, it is found off Cape Verde and Senegal, and from Nigeria to Namibia; there is a one record in the Mediterranean off the coast of Crotone, Italy.
It can be found along the continental margin of the Indian Ocean, from eastern South Africa to the Arabian Peninsula (including Madagascar, the Seychelles, and Mauritius), to Southeast Asia and northern Australia.
Its range extends into the Pacific, northward to the Philippines and southern China, and eastward to New Guinea and some Micronesian islands.
Pigeye sharks, chiefly juveniles, are not strongly migratory and tend to remain in a local area. The longest recorded distance covered by an adult is 670 miles. Home ranges are around 12 square miles and increases slightly as they age.
Juvenile Pigeye sharks in northern Queensland stay in Cleveland Bay year-round where strong currents flow and there is high turbidity. The juveniles generally stay in water less than 130 feet deep, swimming into the intertidal zone with the rising tide and depart as the tide recedes. This may be to scavange on the submerged mud flats, or to avoiding predation or competition by staying out of the deeper waters occupied by larger sharks. Juveniles move closer to the river mouths during the dry season and farther from them during the wet season; since the rainy season brings a higher flow of fresh water into the bay, the sharks may be responding directly or indirectly to the resultant decrease in salinity and dissolved oxygen levels; this is an annual movement. Young sharks may stay inshore for up to 3 years.
Diet: Pigeye sharks prefer to hunt close to the sea floor. They will however take food opportunistic or wherever it happens to be in the water. It feeds on fishes such as flatfishes, croakers, and cutlassfishes, and to a lesser extent on cartilaginous fishes, cephalopods, and decapod crustaceans. It has also been recorded eating dolphins, gastropods, sea snakes, and whale carrion.
Aesthetic Identification: The Pigeye shark strongly resembles the Bull shark. Morphology-based phylogenetic studies have considered the two species to be closely related, but so fat all have resulted inconclusive.
The Pigeye shark is buff and robust like a Bull shark and has 5 gill slits, it is counter-shaded grey on top, white belly, and dusky fin tips. The first dorsal fin is large and triangular, with a pointed apex and a concave trailing margin; it originates roughly over the posterior insertions of the pectoral fins. The second dorsal fin is less than a third as high as the first dorsal fin and originates just in front of the anal fin. There is no midline ridge between the dorsal fins. The pectoral fins are long and broad and slightly falcate becoming narrow and pointed at the tips. The anal fin has a sharply notched trailing margin.
Biology and Reproduction: Parasites documented from the Pigeye shark include tapeworms Callitetrarhynchus gracilis, Cathetocephalus sp. Floriceps minacanthus, Heteronybelinia australis, Otobothrium australe, O. crenacolle, and Protogrillotia sp. Also, the myxosporean Kudoa carcharhini, the copepods Pandarus smithii and P. cranchii.
The Pigeye shark is viviparous. Reproduction varies among regions: off South Africa, the gestation period lasts about 12 months, with mating and birthing both occurring in late summer. The litters range from 3 to 7 pups with an overall average of 5. Newborns are around 30–31 inches long.
Off northern Australia, the gestation period lasts 9 months, with birthing taking place in November and December. The litters range from 6 to 13 pups with an average of 9 and the newborns are around 23–26 inches long.
Pigeye sharks grow slowly, and live long lives. Male sharks do grow faster and reach a smaller definitive size than females. Sexual maturity is reached at around 6.9 feet long and 12 years of age for males, and 7.2 feet long and 13 years of age for females. The maximum lifespan of a Pigeye shark is at least 26 years for males and 30 years for females.
Behavioral Traits, Sensing and Intelligence: The Pigeye shark is a largely solitary animal, though occasionally several individuals may be found at the same location. Research suggests that in some locations it is competitive with the Bull shark. Young pigeye sharks are potentially vulnerable to predation by larger sharks.
LATEST RESEARCH: The Pigeye shark can be most reliably distinguished from the Bull shark by the number of precaudal (before the caudal fin) vertebrae (89–95 in C. amboinensis versus 101–123 in C. leucas). Externally, it has a greater size difference between its dorsal fins (first-to-second height ratio >3.1:1 versus ≤3.1:1 in C. leucas) and the notch in its anal fin margin forms an acute angle (versus a right angle in C. leucas). This species also usually has fewer tooth rows in the lower jaw (10–12 on each side versus 12–13 in C. leucas).
Pigeye (Java) Shark Future and Conservation: Pigeye sharks are caught occasionally on longlines and in gillnets and is used for meat and fins. As a predator, the shark can accumulate ciguatera toxins produced by dinoflagellates within its tissues and can be poisonous to humans. In KwaZulu-Natal, South Africa, small numbers of Pigeye sharks are caught in shark nets set up to protect beaches.
Pigeye (Java) Shark Recorded Attacks on Humans: Potentially dangerous, but no recorded attacks.