The Grey Nurse Shark

(Carcharias Taurus)

The Grey nurse is large, stocky shark with adults reaching up to 4 meters in length and being around 1 meter at birth.
The Grey Nurse is a Grey to brownish-grey shading from dark above to light below and often with scattered dark spots on it's sides. It has a rounded mouth, extending behind the eyes, located below the flattened snout. The dorsal, ventral and anal fins are of similar size with the pectoral fins just behind the gill slits. They have small slit like eyes (quite a feline appearance).

Usually sighted during the months from April to November. The Grey Nurse Shark can be found along the east, west and northern coasts on Australia, migrating south in winter. With them being not as far south as Tasmania and rarely sighted in the Bass Strait region. They live in the shallow coastal waters down to a depth of 60 meters, although has been recorded at 190 meters.

Numbers have declined dramatically over the last decade, and the species may become extinct in the near future. 98% of grey nurses are now found at only 8 sites. Numbers have declined from all other sites. Reasons for the decline include:

• they only produce one pup per female per year (juveniles develop teeth within the uterus when they are about 100mm long, and then hunt and eat each other in the uterus. In a kind of “grey nurse weakest link” competition, only the strongest pup survives to be released into the sea)
• they haven't been able to recover from the massive depletion of their numbers in the 1950s, 60s and 70s when they were blamed for most shark attacks and hunted mercilessly
• they are still taken by recreational anglers and are part of the by-catch of commercial operations.

This is all the more reason to treat the grey nurses at South Maroubra with respect. This includes NOT going into their cave. If the grey nurses are driven away from this breeding area, we might not be able to see grey nurses in Sydney at all. But more importantly, their breeding cycle could be interrupted and hence their decline might be accelerated. If you are on a dive and somebody does go into their cave, while not being able to stop them on that dive, have a word with them back on the boat and explain to them why they shouldn't do it. Normally they do this out of ignorance rather than selfishness or stupidity, although there is one diver in Sydney who persists in this behaviour, despite being told on many occasions by various people that he shouldn’t do it.

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