Australian Icons - Ron & Valerie Taylor
Perception, as they say, is reality… and to change the public’s widely held belief that a large & dangerous looking shark such as the Grey Nurse was in fact no danger to them requires exceptional effort. To get politicians to do anything is even harder, but the latter is virtually impossible until the wheels start to turn on the former.
Australian diving icons Ron & Valerie Taylor were amongst the first to realize that the Grey Nurse should actually be protected, rather than hunted, and they were able to both use their high public profiles and enlist an unusual ally to the cause.
Ron, a former world spearfishing champion, told me that when they first started spear fishing back in the late 1950’s both he & Valerie were utterly convinced that the Grey Nurse was a man-eater.
However, over time as they moved more into scuba diving, they came to understand that the Grey Nurse was relatively harmless to man and by the mid 60’s were both actively campaigning for it’s protection.
The Late Peter Goadby
Ron highlighted two key events that helped to turn the tide of opinion, with the first being enlisting the help of Australian game fishing legend Peter Goadby.
Peter Goadby added significant weight to the conservation argument by confirming that the Grey Nurse was not a game shark at all.
Game fishermen in the late 1960’s were not known for their environmental or conservational predisposition… so having such a well-known personality as the late Peter Goadby on the side of the Grey Nurse was a huge coup.
The second event was the film Ron & Val made in 1973 called the Vanishing Grey Nurse, which went to air as part of a series of 13 thirty-minute documentaries made for Channel 9 called Taylor’s Inner Space. The film was the first to challenge the public’s perception of the Grey Nurse & introduce the reality of the situation and it played a significant role in changing public opinion.
The fight to protect the Grey Nurse from extinction was helped by numerous other people, many of whom went to great lengths, then in 1984 a major breakthrough was achieved when the state government of New South Wales formerly declared the Grey Nurse as ‘vulnerable’ – making it the first protected shark in the world.
The lead of New South Wales was eventually followed in Queensland, Western Australia & Tasmania with fisheries legislation to protect the Grey Nurse, then it was listing as ‘critically endangered’ under Australian Federal Government Commonwealth legislation.
The Swiss based International Union for Conservation of Nature (IUCN) has also listed it as vulnerable, meaning the Grey Nurse faces a high risk of endangerment in the wild – one step down from high risk of extinction in the wild.
Diving Australia: Grey Nurse Sharks – Spot-A-Shark Website
In 2007 I was on board the ProDive Sydney dive-boat one Saturday morning heading for one of my favorite dive sites in Sydney – the very popular Grey Nurse aggregation site Magic Point.
Camera Rig
ProDive picks up divers first in Rose Bay on the southern side of Sydney harbor and then heads north to pick up the rest in Manly. I usually get on board in Rose Bay and am always interested to see who else is on board as it’s quite common to bump into people you have not seen for a while.
At Manly there were several divers joining the trip and I noticed one of them had a rather unusual looking video camera.
The rig consisted of a regular underwater video housing, but with a long flat bracket across its bottom and waterproof laser lights clamped to it either side of the housing.
Curious…I introduced myself and asked what the contraption was for? It turned out that its owner, Sean Barker, was working on a project to identify sharks using something called I3S – Interactive Individual Identification System – for his honors degree in Marine Science.
Dive Log "Wanted Poster"
I subsequently learned that I3S is a software program that works on the basic premise that the pattern of spots on the flanks of the Grey Nurses are unique, in the same way that fingerprints are with humans.
Therefore if sufficient images can be collected from the locations where Grey Nurse are known to congregate, then migration patterns can be identified.
While the spot pattern remains the same, the distance between the spots increases as the shark grows, so I3S also provides a way to determine the growth rate of a previously identified shark, if the dates it is spotted & photographed are known.
The laser lights Sean was using were to introduce a known dimension into the image of the shark so that the growth rate can be calculated.
Sean explained that his problem was getting enough images to build a decent database and being a one-man band meant it was virtually impossible to gather enough to really get his project moving.
Sean Barker & Peter Simpson
So Sean approached Dive Log Australia seeking support for an advertisement requesting copies & dates of Grey Nurse shark images taken in eastern Australia.
The advert produced a strong response and ultimately lead to Sean teaming up with another Sydney based diver, and self-confessed shark addict, Peter Simpson.
Peter had been diving Magic Point regularly since 2000 and had collected lots of images that could be used for the project.
Together Sean & Peter developed the Spot a Shark website which has greatly increased the number of images in the database.
Sean & Peter have now positively identified over 430 sharks and nearly 25 migratory patterns.
Diving Australia: Grey Nurse Sharks - Spot Patterns & I3S
Exactly where the original concept of using the spot patterns came in the first place is not completely clear, but there is no doubt that Australian dive instructor Phil Bowman of Seal Rocks made a major contribution when he incorporated the principle into the PADI specialty “Shark Diver” course he developed back in 1987.
I3S was first conceived in 2003 by Dutch marine scientists Jurgen den Hartog & Renate Riejns while in South Africa studying the impact of divers on the Ragged Tooth (Grey Nurse) Shark at Aliwal Shoal, 40km south of Durban. They were diving with Anna Mieke van Tienhoven, who had published the idea of using the spot patterns on the flanks of the shark as a kind of unique identity fingerprint, but was using manual comparison to do the analysis – something that got harder & more time consuming the more sharks she photographed.
What Hartog & Riejns did was develop the theory of using a software algorithm to compare spot patterns, based on the principle that the pattern on each shark is unique. The I3S software they developed stores the pattern as a “fingerprint file” and uses that to compare each additional image added to the database.
Although initially for use in identifying Grey Nurse Sharks the I3S software has been used successfully with Whale Sharks identification, as they also have unique spot patterns, and a modified version has been used in the identification of Manta Rays.
Website: www.reijns.com/i3s/
Diving Australia: Grey Nurse Sharks - Breeding Cycle
Grey Nurse sharks breed slowly and are ovoviviparous, which means the embryos feed on a yolk sac in the mother’s uterus until all the yolk is consumed, when they turn on each other in what is known as “intra-uterine cannibalism”.
There are upto 15 embryos initially but this Darwinian survival of the fittest process results in only one pup actually making it, meaning a maximum of two pups per litter – one from each of the mother’s two uteri.
The pups are between 80 to 100cm in length when they are finally born, meaning they are quite small and relatively vulnerable to attack, further adding to the pressure on the overall Grey Nurse population.
The gestation period is believed to be 9 to 12 months and the overall reproductive cycle about two years, because the mother rests for a year or so before mating again.
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