The word 'shark' is used to describe a broad range of aquatic creatures, but not all sharks are dangerous to humans. Nearly all fatal attacks in coastal waters are attributed to just three species: Bull Sharks, Tiger Sharks and White Sharks (also known as white pointers).
Alternative names: River Whaler, Freshwater Whaler, Swan River Whaler.
The Bull Shark, Carcharhinus leucas, is found along coastlines in tropical and subtropical oceans, and in Australia occurs from central NSW coast, across the northern coast to Perth, Western Australia.
Bull Shark distribution extends south to Sydney during the warmer summer months. It is the only widely distributed shark that penetrates far into fresh water for extended periods where it sometimes breeds. Females normally give birth in estuaries and river mouths and the young can remain in the river for up to 5 years.
It is a dangerous shark due to its aggressive nature, powerful jaws, broad diet, abundance, and its habitat preference for shallow, murky inshore waters. It has a short snout which is wider than it is long, hence the name. Adults can range from 2 to 3.5 metres in length and up to 230 kg in weight. Bull Sharks will eat almost anything including fish, other sharks and rays, turtles, birds, molluscs, crustaceans and dolphins. The teeth are triangular, saw-edged and very sharp. The belly is usually off-white, the top surface grey and the eyes small.
Alternative names: White Pointer, White Shark, White Death.
White Sharks, Carcharodon carcharias, are found near shore along most of the world's temperate coastlines but are relatively scarce compared to most other widely distributed shark species.
In Australia, White Sharks have been recorded from central Queensland, around the southern coast to North West Cape, Western Australia, but are more common in the south.
Only the underbelly is white: the top surface is grey to blue/grey or bronzy.
The biggest recorded specimen was 7 metres long and 3200 kg.
The teeth are large, saw-edged and triangular. The diet of young great whites (under about 3.5 metres) is mainly a variety of fish, rays and other sharks. Larger adults eat larger prey including marine mammals such as sea lions and seals, small toothed whales and otters. They also eat dead animals floating in the water. More attacks on humans, including many fatalities, have been attributed to the White Shark than to any other marine animal. Great Whites are a protected species in many Australian states including NSW, and also in several other countries.
Tiger Sharks, Galeocerdo cuvier, are found worldwide in warm tropical and subtropical seas where they inhabit both shorelines and open waters.
In Australia, they occur across northern Australia, and south to southern NSW and Perth in Western Australia.
The species is most active at night, when it comes closer inshore or nearer the surface. It is also one of the few sharks which is a true opportunistic scavenger, taking a wide range of prey including fish, turtles, crabs, clams, mammals, sea birds, reptiles, other sharks and just about anything else they can catch alive, as well as a variety of inanimate flotsam items.
Its occurrence in shallow water, indiscriminate diet and large size make it one of the most dangerous sharks. The species has tiger-like, striped markings on a dark, grey-brown back with off-white underbelly. They can grow to around 6 metres but on average are about 3 metres. The teeth are heavily saw-edged, cockscomb shaped, razor-sharp, and the same in both upper and lower jaws.
References: Sharks and Rays of Australia (2nd ed.); Peter R. Last and John D. Stevens, CSIRO Publishing, Collingwood VIC 3066, 2009, various pages.
There are numerous other species of sharks found right along the NSW coastline, most of which are not considered dangerous to humans, although any of the larger sharks could pose a risk to humans under certain circumstances.
For example, the Australian Shark Attack File lists instances where divers have pulled the tails of otherwise disinterested sharks, usually Wobbegongs, and subsequently been bitten. Similarly, Whaler Sharks feeding in schools of bait fish or salmon may inadvertently bump or bite surfers and/or their surfboards. Other parts of this guide will identify some of those circumstances where there is a potentially increased risk of attack. The following descriptions are of some of the more common species known to occur off the NSW coast, especially during the warmer summer months.
Notorynchus cepedianus have seven gill slits where most sharks only have five, plus a single dorsal fin set well back on the body which is grey or brownish on top and sprinkled with light and dark spots. It is widespread geographically in temperate waters but is limited in numbers.
In Australia, they occur along the south coast, from about Sydney in NSW to Esperance in Western Australia, including Tasmania. Recorded to depths of 150 metres, but usually cruises coastal sandy bays and rocky shorelines up to the surf line where it moves in and out with the tide seeking prey such as other sharks and rays, bony fish, seals and carrion.
Bronze Whalers, Carcharhinus brachyurus, inhabit many temperate seas and oceans around the world. They are often seen close inshore feeding on schooling fish such as salmon but are also found near deep water where they prey on squid and bottom-dwelling fish. They are large, up to 3.5 metres and 300 kg, are potentially aggressive sharks that have attacked people and can be dangerous to spearfishers with fresh catches as well as towards surfers, as their natural prey is often found in the surf zone. Colour is grey to bronze on the back, and white below. The pelvic and pectoral fins can have dusky to black tips.
Greynurse Sharks have large, stout bodies tapered at both ends, a pointed snout and small eyes. They have two large top (or dorsal) fins of similar size.
The upper surface of Greynurse Sharks is bronze coloured and the underside is paler. Juveniles often have dark spots on the lower half of the body and the caudal fin. These spots fade as the shark becomes larger, but are sometimes still seen on adults.
Greynurse Sharks can grow to at least 3.2 metres in length. They are a large shark native to subtropical to cool temperate waters in the Mediterranean Sea and the Atlantic, Indian and western Pacific Oceans. Once widely distributed, they are now mainly restricted to Australia and the east coasts of the USA, Uruguay, Argentina and South Africa. In Australia there is an east coast and a west coast population.
The east coast population is found predominantly in inshore coastal waters along the coast of NSW and southern Queensland. There are a number of key habitat sites along the coast of NSW and southern Queensland where they are regularly found in groups. These sites generally have sandy-bottomed gutters or rocky caves and are in the vicinity of inshore rocky reefs or islands.
They shelter in caves or gutters during the day and emerge to feed at night on bony fishes such as mackerels, other sharks and rays, squids, crabs and lobsters.
There are nine species of hammerhead sharks, three of which are known to occur in NSW waters: the Smooth Hammerhead, Scalloped Hammerhead and Great Hammerheads.
In Australia, Smooth Hammerheads occur south from Coffs Harbour to about Jurien Bay, Western Australia, and are the most common of the hammerheads in NSW. Females are thought to give birth in nearshore waters of the NSW coast between January and March, when they are often observed in large schools swimming just outside the surf zone of NSW beaches.
The Scalloped Hammerhead is recorded throughout the north from Sydney NSW to Geographe Bay in Western Australia. The Great Hammerhead prefers tropical and warm temperate seas, and occurs north from Sydney NSW to the Abrolhos Islands off Western Australia.
Hammerheads range from under 1 metre, up to the Great Hammerhead (Sphyrna mokarran) averaging 3.5 metres, but with a largest reported size of 6 metres and 450 kg.
Great Hammerheads have a wide, thick head with eyes at the margins of the hammer which is almost rectangular in shape. It is greyish brown above and off-white below, and is found in temperate to tropical waters worldwide along coastlines, the continental shelf and adjacent drop-offs to about 80 metres.
A migratory predator with a good sense of smell, it eats fish, squid, octopus, crustaceans and, in particular, stingrays.
Both the Shortfin Mako, Isurus oxyrinchus, and its longfin cousin, Isurus paucus, are commonly called Mako Shark.
On average the shortfin species, found in offshore temperate and tropical waters to depths of 150 metres, reaches around 3.2 metres and 400 kg. It occurs along the entire NSW coast, and is widespread in most of Australia's coastal shelf and ocean waters. Colour is bluish black with a white underside and a hydrodynamic shape which provides spectacular speed and agility.
Prey is mainly bony fish as well as other sharks, sea turtles, herons, dolphins and possibly scavenged long-lined and netted fish. Makos are renowned for their ability to leap out of the water and cases of angry Makos jumping into boats after being hooked have been recorded.
Oceanic Whitetip, Carcharhinus longimanus, is an aggressive but slow-moving fish found globally in the upper layers of deep ocean waters, usually between 20° to 28°C temperature.
The most common ship-following shark, it is a danger to survivors of oceanic shipwrecks and downed aircraft but poses minimum threat to inshore swimmers or surfers. Once extremely common, numbers are now in steep decline as its large, wing-like pectoral and dorsal fins are highly valued as ingredients of shark fin soup. Colour, which can vary by region, ranges between bronze, brown, bluish or grey above and white, or occasionally yellow tinged, below. Maximum recorded size is 4 metres but usually does not exceed 3 metres.
At least eight species of Wobbegongs are known from Australian waters, with three found along the NSW coast. The ornate Wobbegong (Orectolobus ornatus) is distributed from Port Douglas in North Queensland to Sydney in the south.
The Spotted Wobbegong (Orectolobus maculatus) is also found along Australia's east coast from about Gladstone in central Queensland, around southern Australia to Western Australia. The third NSW Wobbegong is the Banded Wobbegong (O. halei), which ranges around the south of the continent from southern Queensland to southern Western Australia.
The largest species, the Spotted Wobbegong can grow to 3.2 metres in length, although seldom exceeds 160 cm in NSW. The name is believed to be of Aboriginal origin meaning 'shaggy beard' after skin flaps around the mouth. Well camouflaged with bold, symmetrical carpet-like markings, Wobbegongs, like most other sharks, are not dangerous unless provoked.
They have bitten divers who poked or hindered them and people who accidentally trod on them in shallow water. Their small but sharp teeth can penetrate a wetsuit, and having bitten they may hang on and be very difficult to remove.