Preliminary results of the Great Fiji Shark Count, April 2012
In the month of April, 3,693 divers recorded their shark sightings during 855 dives.
In the month of April, 3,693 divers recorded their shark sightings during 855 dives.
The guitarfish/wedgefish (Rhynchobatus australiae), also called the white-spotted guitarfish or white-spotted wedgefish, is a species of fish in the Rhynchobatidae family. The guitarfish/wedgefish are known for an elongated body with a flattened head and trunk and small ray like wings.
The whale shark, Rhincodon typus, is a slow-moving filter feeding shark. It is the largest extantfish species. The largest confirmed individual had a length of 12.65 metres (41.50 ft) and a weight of more than 21.5 tonnes (47,000 lb), and there are unconfirmed reports of considerably larger whale sharks. This distinctively-marked fish is the only member of its genus Rhincodon and itsfamily, Rhincodontidae (called Rhinodontes before 1984), which belongs to the subclassElasmobranchii in the class Chondrichthyes. The species originated about 60 million years ago.
The whale shark is found in tropical and warm oceans and lives in the open sea with a lifespan of about 70 years. Although whale sharks have very large mouths, as filter feeders they feed mainly, though not exclusively, on plankton, which are microscopic plants and animals. However, the BBC program Planet Earth filmed a whale shark feeding on a school of small fish. The same documentary showed footage of a whale shark timing its arrival to coincide with the mass spawning of fish shoals and feeding on the resultant clouds of eggs and sperm.
The blue shark (Prionace glauca) is a species of requiem shark, family Carcharhinidae, that inhabits deep waters in the world’s temperate and tropical oceans. Preferring cooler waters,[clarification needed] blue sharks migrate long distances, for example from New England toSouth America.
Although generally lethargic, they can move very quickly. Blue sharks areviviparous and are noted for large litters of 25 to over 100 pups. They feed primarily on small fishand squid, although they can take larger prey. Blue sharks often school segregated by sex and size, and this behavior has led to their nickname “wolves of the sea”.
The silky shark (Carcharhinus falciformis) is a species of requiem shark, family Carcharhinidae, named for the smooth texture of its skin. It is one of the most abundant sharks in the pelagic zone, and can be found around the world in tropical waters. Highly mobile and migratory, this shark is most often found over the edge of the continental shelf down to a depth of 50 m (164 ft).
The silky shark has a slender, streamlined body and typically grows to a length of 2.5 m (8 ft 2 in). It can be distinguished from other large requiem sharks by its relatively small first dorsal fin with a curving rear margin, its tiny second dorsal fin with a long free rear tip, and its long, sickle-shapedpectoral fins. It is a deep, metallic bronze-gray above and white below.More info here…
This aggressive but slow-moving fish dominates feeding frenzies, and is a danger to shipwreck or air crash survivors. Recent studies show steeply declining populations because its large fins are highly valued as the chief ingredient of shark fin soup and, as with other shark species, the whitetip faces mounting fishing pressure throughout its range.
The great hammerhead (Sphyrna mokarran) is the largest species of hammerhead shark, family Sphyrnidae, attaining a maximum length of 6.1 m (20 ft). It is found in tropical and warm temperate waters worldwide, inhabiting coastal areas and the continental shelf.
The great hammerhead can be distinguished from other hammerheads by the shape of its “hammer” (called the “cephalofoil”), which is wide with an almost straight front margin, and by its tall, sickle-shaped first dorsal fin. A solitary, strong-swimming apex predator, the great hammerhead feeds on a wide variety of prey ranging from crustaceans and cephalopods, to bony fishes, to smaller sharks. Observations of this species in the wild suggest that the cephalofoil functions to immobilize stingrays, a favored prey. This species has a viviparous mode of reproduction, bearing litters of up to 55 pups every two years.
They are large sharks with blunt, broad snouts, narrow bent cusps on the upper teeth, and no interdorsal ridges. They are gray to bronze in color on the dorsal side, white on the ventral side.
The fins have similar coloring with the exception of the pelvic fins, which have dusky tips, and the pectoral fins, which have dusky to black tips.More info here…
Zebra sharks get their name from their juvenile appearance: dark bodies with yellowish stipes. As they become adults their coloring changes to a light tan with small dark spots. This adult appearance leads to them often being mistakenly called Leopard sharks. The Zebra shark has a distinctive long tail that is almost as long as the body and prominent ridges that run the length of the body.More info here…
Scalloped Hammerhead Sharks (Sphyrna lewini) are probably the most commonly found species of hammerheads located in coastal regions, appearing in very shallow waters such as estuaries and inlets. Their distribution in the water reaches from the surface down to a depth of approx. 275 m. The young, however, remain mostly in shallow waters along the shore to avoid the danger of falling into the mouths of predators. At certain times of the year and places, and during certain phases of their lives, scalloped hammerheads form very large schools, sometimes counting hundreds of individuals, but they also swim the oceans alone. Some populations remain stationary, others clearly wander, migrating in the direction of the poles in summer. Some sexually-related migrations have also been observed, e.g. females who undertake migrations during particular periods of their sexual development.More info here…
Simple ID points:
A large elongated shark that can reach lengths of up to 3 meters, Sicklefin Lemons are identified by their tan color (hence the name), two rather large and nearly equal sickle-shaped dorsal fins, sickle-shaped pectoral fins, small eyes and a distinctive black spot on the tip of their snout. On Shark Reef, they are frequently confused with the Tawny Nurse Sharks from which they however differ by their continuously open, tooth-studded mouth and by having a proper “sharky” tail.
Like the Silvertips with whom they share an undeserved bad reputation, Lemons appear completely unfazed by divers which they will approach closely.
The best time to encounter Lemon Sharks is between October and December in Fiji.More info here…
The tawny nurse shark (Nebrius ferrugineus) is a species of carpet shark in the family Ginglymostomatidae, and the only extant member of the genus Nebrius. It is found widely along coastlines in the Indian and Pacific Oceans, preferring reefs,sandy flats, and seagrass beds from very shallow water to a depth of 70 m (230 ft). With a cylindrical body and a broad, flattened head, the tawny nurse shark is quite similar in appearance to the nurse shark (Ginglymostoma cirratum) of theAmericas, from which it can be distinguished by its pointed-tipped dorsal fins and narrow, sickle-shaped pectoral fins. The maximum recorded length is 3.2 m (10.5 ft).More info here…
The Blacktips are small sharks that hunt fish in very shallow water and are thus rarely encountered by divers. The juveniles however often aggregate in mere centimeters of water within sandy lagoons and are thus frequently encountered by swimmers, snorkelers and beachcombers who spot the black tips of their dorsal fins sticking out of the water.
This is a beautiful small shark of about 1.5 meters in length that can be easily identified by the brilliant black tips with a bright white highlight on both dorsal fins, black tips on the lower lobe of its tail and the anal fin and its tan color with a striking white dash extending from the tail into its flanks.More info here…
The Oceania fantail (blue spotted) ray (Taeniura lessoni), named for René Lesson, the the French scientist in the 19th century who once worked on members of this genus in Melanesia.
The Giant reef ray (Taeniurops meyeni) is a species of stingray in the family Dasyatidae, found throughout the nearshore waters of the tropical Indo-Pacific, as well as off islands in the eastern Pacific. It is a bottom-dwelling inhabitant of lagoons, estuaries, and reefs, generally at a depth of 20–60 m (66–200 ft).
Reaching 1.8 m (5.9 ft) across, this large ray is characterized by a thick, rounded pectoral fin disc covered by small tubercles on top, and a relatively short tail bearing a deep ventral fin fold. In addition, it has a variable but distinctive light and dark mottled pattern on its upper surface, and a black tail.More info here…
The Maskray (Neotrygon kuhlii) or Kuhl’s stingray, is a species of stingray of the Dasyatidae family. This ray is currently under investigation by geneticists and it is very likely that it will be reclassified in the near future, possibly as Neotrygon trigonoides.
The Maskray is light green with blue spots, but appears grey in the water with pointed wings and a disk width around 42 centimeters (17 in). It is sometimes confused with the smaller Oceania Fantail (Blue Spotted) Ray, which is rounder with brighter blue and more vivid spots.More info here…
Throughout the months of April and November every year, you have the opportunity to help celebrate and record Fiji’s amazing coral reef biodiversity, show you care about our world’s delicate coral reef systems, and have fun, by taking part in the FIJI-WIDE SHARK COUNT!
Easy to do, this is suitable for visitors and locals alike, whether you like to fish, snorkel, or SCUBA dive. We hope that tourists, school children, scientists and all people with an interest in the marine environment will take to the reefs with us to search for the Sharks of Fiji!
The Great Fiji Shark Count will be held across Fiji every April and November every year.
You can do a single count, or take part as many times as you like during that month, so that you cover different reefs. All data will be gratefully accepted!
So, see your resort, watersports operator or travel agent, get your Shark identification materials and dive into the beautiful blue waters of Fiji, to be a part of history!