grey nurse shark

One of the first shark species to be protected was the grey nurse shark (Carcharias taurus). The biology, distribution and conservation of this species are dealt with in the following paragraphs with a main focus on Australia as it was here it first became protected.

The grey nurse shark, Carcharias taurus, also called the ragged-tooth shark, is an elasmobranch and belongs to the odontaspididae (ragged-tooth) shark family. It can easily be recognized by its characteristic conical snout and under hung jaw. Both jaws are lad with sharp, long and pointed teeth. The head is flatted and it has a large and stout body, which ranges up to 3.2 m and may weigh up to 300 kg. The body is grey to grey-brown dorsally and off-white on the belly. The juviles (young sharks) usually have dark spots on the upper two-thirds of the body. The first and second dorsal fins are of similar size and the caudal fin is asymmetric. Once believed to be a man-eater, it is now known that this shark rarely attacks humans and if it does it is only in defse, or if it is baited.

Sharks are the top predators in our oceans, and as such they are important for the marine ecosystems as important regulators of other species. They eat the weak, the old and the dead animals. The grey nurse sharks eat mainly lobsters, crabs, smaller sharks, fish, rays and squid.

Did You Spot The Difference Between A Grey Nurse & Great White?

Grey nurse sharks live near the coast in sub-tropical to cool-temperate waters near most contintal land masses (not found in the eastern Pacific Ocean off North and South America). They have a preferce for some places resulting in an unev distribution. For example, there are few grey nurse sharks found in north Australia while they are relatively abundant in the southern part of the eastern and western Australian waters.

They are usually found swimming slowly, just above the sea floor, in sandy-bottomed gutters or in rocky underwater caves near inshore rocky reefs and islands. They can be found at depths ranging from 10 m (near the coastline) to 200 m (on the contintal shelf). They are gerally solitary but at times small schools of grey nurse sharks are found swimming and feeding together.

The grey nurse shark is one of the most critically dangered shark species and believed to be the first protected shark in the world. It was declared 'vulnerable' in the waters of New South Wales (Australia) in 1984 and later throughout the world. In 1996 the species was listed globally 'vulnerable' by the International Union for Conservation of Nature (IUCN) and declared 'vulnerable' in Commonwealth waters of Australia. According to the vironmt Protection and Biodiversity Conservation Act 1999 (EPBC Act 1999) it is believed that there are two separate populations of Grey nurse shark in Australia. The population in the east coast is listed as 'critically dangered' whereas the west coast population is listed as 'vulnerable' under the EPBC Act (1999)

Grey Nurse Shark Attacks Spearo

The grey nurse sharks are also protected under the Fisheries Legislation in New South Wales, Western Australia, Victoria, Tasmania and Quesland. In the Northern Territory the species is classified as 'data deficit' by the Territory Parks and Wildlife Conservation Act (2000)NTG.

The population has declined dramatically in rect decades, especially in the 1960s and 1970s. After 20 years of protection the population is still declining and there are approximately 1000-1500 grey nurse sharks left in Eastern Australia.

The grey nurse sharks are particularly vulnerable to these threats due to their late maturation and low breeding success. They reach sexual maturity at the age of three months and give birth to one or two young every second year; thus, the population grows very slowly. Furthermore, their limited distribution and specific habitats

Nurse Shark Cut Out Stock Images & Pictures

Make it difficult for them to migrate to other areas. Beach nets cause the death of hundreds of shark that are caught in the nets and cannot escape.

The increased public awaress has led to the developmt of methods that reduce the uninttional killing of elasmobranch (sharks and rays), turtles and marine mammals. An inexpsive method to reduce by-catch is by using tunnel excluders. These able sharks, turtles and rays to escape and survive. A prototype used by the Dutch achieved a 40-100% reduction of the by-catch of the most vulnerable species.

The size and texture of nets are also of great importance for the survival of larger vulnerable species. Oft smaller nets have be shown to catch the same amount of target fish and reduce the by-catch greatly, especially of the mature sharks.

Grey Nurse Shark Stock Photos, Pictures & Royalty Free Images

And a new method, taggingCSIRO, can reveal their preferred forage and breeding areas. A good example of managed marine areas is to be found in Jervis Bay, NSW.

Jervis Bay has be divided into time zones, some for fishing and some for diving, and the strategy has be approved by both fisherm and divers. However, “Divers that regularly dive at places like South West Rocks in New South Wales will tell you that up to 70 per ct of the sharks there are trailing hooks from line fishing.” says Nicola Beynon from the Humane Society International (HSI). Another widely used method for preserving sharks is eco-tourism such as scuba diving,

And that the sharks' behaviour is monitored. Feeding and touching of marine animals should be strictly discouraged since it can alter their behaviour, and result in long lasting and severe stress to the animals. Divers have noticed sharks altering their behaviour due to increased hierarchy behaviour around killing areas. The lowest in the hierarchy become stressed and exhibit unpredictable behaviour, which could result in attacks on humans.It’s now appreciated that this shark is more like the family Labrador and harmless to people, unless provoked. Nevertheless, that previous mistaken image saw it hunted relentlessly by people during the late 20th century, which contributed to its numbers crashing in Australian waters and elsewhere around the world.

Species Spotlight: Grey Nurse Shark — Defend Them All Foundation

In 1984 this species became the first shark anywhere in the world to be safeguarded under an act of parliament, when it was declared a protected species in New South Wales waters. Grey nurse sharks now continue to be protected under fisheries legislation in waters off NSW, Western Australia, Tasmania and Queensland.

The grey nurse shark, which is also known as the sand tiger shark and spotted ragged-tooth shark, is found worldwide in tropical to temperate coastal waters. In Australia, it occurs in two distinct and geographically separate populations – one on the east coast, the other on the west coast. The east coast population is critically endangered. The conservation status of the west coast population is vulnerable.

Sharks in the east coast population have been reported from all the eastern states but are mostly encountered from southern Queensland down the NSW coast. Along that section of coast there are several sites where the species forms aggregations that are thought to be important for mating and pupping.

Protecting Our Grey Nurse

Despite being widely protected, the species has been slow to recover from the slaughter it endured in the 20th century. It continues to be incidental bycatch in some fisheries and is also caught in nets set across beaches to protect swimmers, particularly along east coast beaches.

However, these continued threats aren’t enough to explain why grey nurse numbers haven’t bounced back since the species became protected. The main reason why is the species’ unusual reproductive physiology, which sees the females produce no more than one pup per year. Grey nurse shark reproduction is governed by a strategy known as intrauterine cannibalism, which means that ultimately females give birth to no more than two live young at a time.

Each female has two uteri in which a number of eggs are produced and from which baby sharks hatch. However, the strongest of these hatchlings eats the others meaning that only one pup can ever survive in each uterus.

Sand Tiger Shark Grey Nurse Shark Stock Photos, Pictures And Images

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Stock Photo Of Grey Nurse Shark (carcharias Taurus) Close Up Of Teeth And Nose, Steinhart.... Available For Sale On Www.naturepl.com

In stock now: Australian Geographic Note Books! Embossed with Australian Animals, these premium notebooks are perfect for Back To School. Shop NowThe Greynurse Shark is a distinctive fish which is usually grey-brown on top and a dusky white underneath. Both dorsal fins and the anal fin are of a similar size.

Juveniles have reddish or brownish spots on the posterior (back) half of the body and tail. These spots often fade as the shark ages, but are sometimes still visible on adults.

The Greynurse Shark lives in shallow coastal waters from the surf zone down to 60 m, although it has been recorded from water as deep as 190 m.

Grey Nurse Shark, Montague Island

The Greynurse Shark occurs in tropical and temperate waters in the Atlantic, Indian and western Pacific Oceans, although the species is known by different common names in different regions. It is recorded from all states

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