Belinda 2022
GREY NURSE SHARK
GREY NURSE SHARK
Scientic name: Carcharias taurus
Family name: Odontaspididae family
PURPOSE OF RESEARCH
Why did I choose this animal? I have never seen a shark alive and wanted to know more about them.
LIFESTYLE
The grey nurse shark is also called the spotted ragged-tooth shark, sand tiger shark and blue nose shark.
In the wild the lifespan of the grey nurse shark is unknown, however those in captivity can live between 13-16 years. They are found alone or in small schools with larger groups occurring during courtship and mating.
Male sharks reach sexual maturity at 4-6 years of age, and females at 6-8 years. Both males and females reach a total length of about 3.6m. Pups measure an average of 1m in length at birth.
Breeding grey nurse sharks mainly occurs in autumn and is followed by a 9-12 month gestation period and have two pups per litter, breeding once every two years. The male has a visual distinctive sexual organ called claspers, which are extensions of the pelvic fins which he uses hold the female grey nurse shark in place until sperm can be transferred and stored in the female uterus.
PHYSICAL FEATURES
These sharks have large, stout bodies, a pointed snout with many rows of visible teeth and small eyes. Both jaws have sharp, long pointed teeth. The head is flattened and has a large body and stout. The body is grey–brown dorsally and off-white on the belly.
Young sharks (juveniles) have dark spots on the up two-thirds of the body and two large dorsal fins of similar size. Sharks do not have bones - they are made of cartilage.
HABITAT
Grey nurse sharks live near the coast in sub-tropical to cool-temperate water near most continental land masses. It resides in the sunlit zone about 20 metres (65 feet). Their preferred habitats have sandy-bottomed gutters or rocky caves, reefs or island.
There are two populations of grey nurse sharks in Australia - the east coast population lives along the coast of New South Wales and Southern Queensland and the West Coast population lives in the South West waters of Western Australia.
Their diet consists of fish, smaller sharks, rays, squid, crustaceans such as crabs and lobsters. Sharks work together in a group so they can feed and gather on schools of fish into tight bunches before catching and eating them.
They are more active at night during feeding time and as it is dark it is easy for them to sneak up on food to get their catch. They are predators they are able to shift their prey’s habitats which changes the diets of other species.
It is not aggressive, but may be dangerous if provoked or concerned. It rarely attacks humans and if it does it is only in defence, or if it is baited.
ENVIRONMENTAL THREATS
The grey nurse shark is protected in Australia and has two separate populations under the Environment Protection and Biodiversity Conservation Act 1999.The east coast population is listed as critically listed endangered. The west coast population is listed as vulnerable.
The east coast population has undergone a very severe reduction. It is no longer found at several sites where it was dominant during the 1950’s and 1960’s. These sites include Brush Island and Jervis Bay where, in the 1950-60s, aggregation of 40+ could be observed.
The reduction in population is due to impacts such as fishing, commercial and recreational and shark control activities, beach meshing program and drum lines. Illegal fishing still occurs, with accidental capture by both commercial and recreational fishers occurring as sharks swim in favoured fishing sites.
The Australia Government Department of the Environment has an objective to assist with the recovery of the Grey Nurse Shark in the wild, throughout its range in Australian waters.
The specific objectives of this recovery plan are to:
Develop and apply a monitoring system of the population status (distribution and abundance) and potential recovery of the Grey Nurse Shark in Australian waters.
Quantify and reduce the impact of recreational fishing on the Grey Nurse Shark through incidental (accidental and/or illegal).
Where practicable, minimise the impact of shark Control activities on the Grey Nurse Shark.
ENVIRONMENTAL SOLUTIONS
Investigation and manage the impact of ecotourism on the Grey Nurse Shark.
Manage the impact of aquarium collection on the Grey Nurse Shark.
Improve understanding of the threat of pollution and disease to the Grey Nurse Shark.
Continue to identify and protect habitat critical to the survival of the Grey Nurse Shark and reduce the impact of threatening processes within the area.
Continue to develop and implement research programs to support the conservation of the Grey Nurse Shark.
Promote community education and awareness in relation to the Grey Nurse Shark conservation and management.
How to improve species existence
Tell divers how to behave around Grey Nurse Sharks to help protect the species and its habitat.
Don’t buy souvenirs like teeth or jaws.
A community grant in the Eastern and Western tuna and billfish fishers is working together with commercial fishers to trial de-hookers and line-cutters in order to safely and quickly remove by-catch from fisheries.
Remove any rubbish or fishing gear that you see in the water or on the beach.
Refrain from fishing in Grey Nurse Shark areas.
If diving, report any tagged Grey Nurse Sharks to the fisheries or the Environmental Protection Agency. Contact the threatened species network in your state.
Participate in volunteer work learn more about threatened species and their habitats.
SUMMARY OF PURPOSE
I have learned how to research and set up scientific papers and have gained confidence in doing animal studies.
Research conducted by Belinda Jensen June 2022