Diving Australia: Diving with Grey Nurse Sharks

Grey Nurse aggregation site at Magic Point in Sydney

Magic Point Grey Nurse aggregation site near Maroubra in Sydney

An underwater encounter with any large creature is an exciting event and the size & physical presence of the Grey Nurse shark makes interacting with them a truly memorable experience.

Most of my experience, and certainly all of my up close & personal, face-to-face contact, has been in the cave at Magic Point off from Maroubra in Sydney.

Typically you are not allowed to enter the cave because of the potential impact on the sharks.

However in the process of getting the images for this site and articles, I was fortunate to be allowed to spend a reasonable amount of time in there – after being extensively coached on what & what not to do.

The work that Sean Barker & Peter Simpson of Spot a Shark have done with Grey Nurse sharks has shown that when they aggregate together at certain times of the year, they establish swimming patterns that keep them away from each other’s “personal space”.

So the presence of a large creature like a diver – with the curtain of bubbles they create – can disturb that pattern, stress the sharks and possibly drive them away from the area.

So in a confined area like the cave at Magic Point, multiple divers entering it is certain to impact the swimming pattern and is a really bad idea.

A lone diver with a slow & cautious approach can enter the cave area successfully, from either end, which minimizes the impact on the sharks and gives them plenty of time to adjust their swimming patterns.

Clear signs of stress are changes in breathing rate, indicated by gaping of their mouths, and the speed at which they flick their tails.

Briefing Map for the Magic Point Dive Site

Magic Point Dive Site Briefing Map

The two are linked because an unstressed Grey Nurse will swim in a relaxed manner at a rate that provides enough oxygenated water passing through its mouth and over its gills.

A stressed shark on the other hand has to move faster to increase the flow of water through the gills, and initially “gapes” its mouth to boost the oxygenation effect.

The stress threshold is around 24 tail flicks per minute, but the shark’s overall “body language” is a sure sign that they are becoming stressed.

If you observe that behavior, take it as your cue to back off and leave them alone – not that you are in any significant danger, but they are a big creature after all and so common sense should prevail….

The exact patterns of migration, aggregation & mating are still not fully understood, but the basic fact is that as divers we are very luck to be able to see the Grey Nurse in it’s natural environment.

Diving Australia: Photographing Grey Nurse Sharks

Patience and preparation are probably the two most important factors associated with getting decent images of the Grey Nurse and it took me a lot of dives at Magic Point before I finally got some publishable photographs.

Visibility at Magic Point is rarely very good in my experience and a “good day” is around 15m, but often it is less than 10m. As with all underwater photography, Rule #1 is get close and Rule #2 is get closer… which at Magic Point is not always possible because of the rules about not going in the cave.

This is where the patience comes in and you need to position yourself along the wall at either end of the cave, assume a non-threatening posture, settle your breathing rate down so that you are not making too much noise and then wait for the sharks to come to you – which they usually will.

Then you need to be prepared with your strobe (or strobes..) extended as far out & back from the camera to minimize backscatter, a shutter speed of at least 1/125 of a second because the sharks are moving objects, your f stop should be open enough to allow adequate light for the background exposure and the power of your strobes adjusted to light the shark.

Composure should place the shark in it’s environment and the focus point should ideally be the eye – we are always drawn to the eye of any creature, but particularly so with large sharks… so the eye needs to be tack sharp!