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Tuesday 19 November 2013

Tiger Time

It's great to catch up with old acquaintances, especially if it happens unexpectedly. But it can be awkward if you have to check their tag to remember their name. Lucky for me, Tiger Sharks don't seem to care about social etiquette.

Filming a familiar Tiger Shark with the 4k Red Epic camera


I've been been away the last couple of weeks on Raine Island with the turtle research group from the Queensland Department of Environment and Resource Management. We were there to monitor the turtle population as they begin the nesting season.

Now as much as I love the turtles, you'll understand if I'm slightly more partial to sharks. During the expedition, I was capturing underwater life, focussing on my study species Tiger Sharks, in UltraHD 4K for Biopixel using the RED Epic camera.

On this particular dive, I was filming some tiger sharks feasting on a turtle. One shark seemed to be more interested in saying 'hello' than joining in on the feed. Judging by the satellite tag attached to her dorsal fin, I guessed I had probably met her before. She certainly knew me! She came in so close that I was able to read the numbers on the satellite tag (if only everyone I met was catalogued like that...)

The satellite tag looked great, with very little fouling and no signs of degradation. My safety diver captured some quick shots of the encounter, and I captured some great close 4K footage to add to the library.

So who was this shark that I had tagged?

After checking her tag numbers, we learned this was Zoe. And as it turns out, Zoe knows me pretty well (awkward!).

The tagged Tiger Shark came close enough for me to read the numbers on her satellite tag (see her dorsal fin)
Zoe was tagged on the March 2013 Raine Island expedition as part of OceanIQ's Turtle and Tiger Sharks project. She is around 3.1m long which means she's a juvenile. Zoe is named after OceansIQ's researcher Adam Barnett's daughter, Zoe. Baby Zoe was a young female herself -  around 5 months in utero - when she accompanied her dad and mum, Katya Abrantes, as they tagged Zoe the shark.

The thing is, this was not the first time we had met Zoe. When we caught her in March this year, she carried the remnants of an acoustic tag. As the only researchers in the area to use these tags on tiger sharks, we were sure this acoustic tag had been fitted by us. We were able to trace this individual shark back to a tagging effort at Raine Island about 2 years ago during the filming of the BBC co-production 'The Great Barrier Reef'.

So it was clear that Zoe had a good reason for approaching me directly - I've caught and tagged her twice!

The tracks from Zoe's satellite tag show she has remained around Raine Island for most of the year. We call this 'site fidelity'. That isn't to say Zoe is around Raine all the time. In April, not long after she was tagged, Zoe was recorded making at return trip to Port Moresby, Papua New Guinea, about 400km away.

Zoe was tagged in March 2013 and in April, was recorded near Port Moresby, Papua New Guinea. This track shows she has spent most of her time around Raine Island, Far North Queensland.

Considering we already have such a great information for this shark and she is not shy, I'm hoping we can recapture Zoe during the next expedition in December, replace the current sat tag with a new one and extend this study period for an individual shark.

Here's hoping she remembers me for the fourth time!

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