The Bull Shark [50]

A Serious Case of Mistaken Identity

By Trevor Gardner

This shark is very, very dangerous. Some experts consider this shark to be the most dangerous in the world, even surpassing the Great White Shark. Surprisingly few people have even heard of it. It has a number of different names both in Australia and around the world and people think they are a different species of shark.

And I was one of them. The first I had heard of the Bull Shark was when a child was taken in thigh deep water at a beach in Florida, USA. Then some guy is tossed off his surf ski in the Georges River in Sydney by a shark. The name Bull Shark comes up again. So, a quick Google search later;

I have an ongoing argument with the game fisherman over the identity of sharks caught. They claim to regularly catch Bronze Whalers, which apart from a few small patches, do not usually inhabit tropical waters. Most have never heard of Bull Sharks.

Not impressed yet. The Bull Shark has been found in most Australian water systems including Brisbane River, Herbert River, Swan River, Clarence River, Daly River, and even Lake Macquarie. Many ‘experts’ believe that the Bull Shark is responsible for most deaths around the Sydney Harbour inlets. Most of these attacks were previously thought to be Great Whites. The Grey Nurse was also blamed in the sixties and seventies. Bull sharks most often reside in water between 30 metres and waist deep.

The Tiger Shark, the Great White and the Bull Shark are the sharks commonly cited as being the most dangerous and responsible for most adverse human encounters. The Bull Shark is said to be the less aggressive of the three but the Bull Shark’s proximity to populated shoreline areas make it extremely dangerous to humans. The Bull Shark is one of the most commonly caught sharks in the world.

The notorious Great White and Tiger tend to live in deeper ocean water and therefore are less immediately dangerous to humans (Australian Museum, 1999). All semantics really. All about being in the wrong place at the right time. However, there are specific behavioural and habitat characteristics of the Bull Shark that should give sea kayakers the heebie jeebies (especially if you are really an estuary/harbour kayaker).

So who is this masked marvel. Only a credit card thief has more alias’ (or is that aliae?). Known by the marine boffins as Carcharhinus leucas, the Bull shark is AKA Cub Shark, Ganges Shark, Nicaragua Shark, River Shark, Slipway Grey Shark, Freshwater Whaler, Estuary Whaler, Swan River Whaler, Square-Nose Shark, Van Rooyen’s Shark, Ground Shark, Euphrates River Shark and Zambezi Shark. The Bull Shark is certainly related to the whaler family and is commonly confused with the Bronze Whaler. Note that many of the Bull Shark aliases include the words estuary and river.

The global habitat of the Bull Shark is extensive, encompassing the majority of tropical and sub tropical coastlines of the world. As mentioned previously Bull Sharks tend to stay close to shore and frequent estuaries, rivers and lakes. One of the most distinctive features of the Bull Shark is the ability to live in fresh or salt water. Bull Sharks have been found 4,000 km upstream in the Amazon river. The Bull Sharks in Lake Nicaragua were thought to be a different species until they were observed jumping rapids, a la salmon, to enter the lake. Bull Sharks tagged in Lake Nicaragua have been later caught in the ocean. In Africa, the Zambezi Shark is known to have caused many deaths among swimmers in shallow water as is the case in the Ramu river in PNG.

The Bull Shark will eat almost anything. The shark seems to favour murky water for hunting. Listed in its diet are fish, sting rays, sharks, turtles, birds, molluscs, crustaceans and dolphins. In southern African rivers cattle and antelope are eaten with tree sloths; dogs, rats and people also recorded amongst Bull Shark prey.

So what does the mystery villain look like? The Bull Shark is heavy bodied with a short nose. The shark is wider in comparison to its length than other sharks giving an almost stout appearance. The female grows to about 3.5 metres and 230 kg and is larger than the male at 2.1 metres and 90 kg. There is a large triangular dorsal fin and moderately large second dorsal fin (about a third the height of the first). The first dorsal fin is more pointed than the second. There is no interdorsal skin ridge between the fins.

Coloured grey (to pale brown) above and off white underneath, there may be inconspicuous pale white bands along the side. The Bull Shark has small eyes and very powerful jaws. The upper teeth are broad, serrated and triangular for cutting chunks of fibreglass. The teeth are very sharp. The lower jaw has more pointed teeth for holding skin-on-frame kayaks.

Is any of this relevant to the average sea kayaker? A common, aggressive, omnivorous and well sized shark that frequents murky water in shallow coastal, estuarine, river and harbour habitats encompassing the entire Australian coastline. You decide.

Bull Sharks are just another reason to:

  1. Learn to roll and not wet exit in the surf zone.
  2. Paddle offshore instead of harbours, rivers and estuaries.

Remember, no one dies from the loss of an arm or leg. They die from blood loss, exposure and drowning. If you get munched, STOP the bleeding as a priority. Direct pressure, compression bandage or tourniquet. Whatever suits you and your training. Me, I’m using the paddle leash. Tourniquet pressure necrosis is not an issue to me if the limb is missing and I am likely to bleed to death at sea.