11 April 2013

Farewell to Kay – Part One

Stuart Buchanan

On Monday, the team at the Two Oceans Aquarium began the process of releasing two ragged-tooth sharks back into the ocean, as part of its ongoing conservation efforts. The first step was to safely remove Kay, a female raggie, from the I&J Predator Exhibit, and place her in a holding tank.

How does one move a shark, you ask? Aquarist Kevin Spiby explains that a diver usually swims above the shark, and using two wooden sticks, gently directs the shark towards a “cone” – a bag designed to safely hoist the shark up and into the moving tank. Except that Kay has clearly enjoyed her time at the Aquarium, and wasn’t too keen to leave! Watch the video below to see Kevin and Kay in action:

Another male juvenile raggie will join Kay on the release today in Gordons Bay. Both sharks were pit tagged with VERBAC tags before going on display, and were also tagged with acoustic VEMCO tags (active for 10 years) on Monday (as seen in the video above) so that their movements can be monitored should they pass one of the many receiver base stations positioned along the South African coast.

Our shark release programme

The Aquarium is receiving support from Gemini Marine, Steve Benjamin of Animal Ocean, Philip de Bruyn and Alison Kock from Shark Spotters in the release today. The sharks’ release forms part of an ongoing release programme which was initiated with the release of Maxine in 2004. Her release set in motion the Save Our Seas Foundation Maxine, Science, Education and Awareness (M-Sea) Programme, an AfriOceans Conservation Alliance (AOCA) initiative, sponsored by the Save Our Seas Foundation. Eight sharks have subsequently been released from the Two Oceans Aquarium since 2004.

The male shark was collected as a juvenile by the Aquarium’s collections team off the Eastern Cape coast and was transferred by air from Cape Town to the National Zoological Gardens (NZG) of South Africa in Pretoria on 24 May 2011, where he was displayed in the Marine Exhibit. “We have an exchange programme in place with the NZG, whereby we loan them juvenile raggies for two years to display in their marine exhibit. This system works well as the sharks have often already spent time in our Aquarium, adjusting to their new environment, and then they head north to act as ambassadors in Gauteng. At the end of the two years NZG returns the sharks to us for release back into the ocean,” said the Aquarium’s operations manager, Tinus Beukes.

Kay has been resident in the I&J Predator Exhibit at the Two Oceans Aquarium since 2009.  She was collected on 10 February 2009 at Hamburg, East London. At that time she measured 149cm in length (notch length) and weighed 51,4kg. On Monday she weighed in at a healthy 207.2kg and measured 202cm - she has grown!

ragged tooth shark two oceans aquarium cape town south africa raggies grey nurse shark sand tiger shark
Taking Kay's measurements before her release. Photo by Stuart Buchanan

More on ragged-tooth sharks

Ragged-tooth sharks are known as grey nurse sharks in Australia and sand tigers in America. They occur in the Atlantic, Indian and Western Pacific Oceans. Ragged-tooth shark populations have been seriously depleted in Australia due to overfishing. As far as we know, South Africa has one of the healthiest populations of ragged-tooth sharks in the world, and these sharks are quite common along the entire sub-tropical east and south Cape coasts. However, while these sharks occur in positive numbers, they require protection and effective conservation management.

ragged tooth shark two oceans aquarium cape town south africa raggies grey nurse shark sand tiger shark kevin spiby
Kay plays hard to get with Kevin! Photo by Stuart Buchanan

Ragged-tooth sharks attain a maximum total length of about 3,2m and a maximum age of about 30 years. They go through about 30 000 teeth in a lifetime.

Click here for Part Two of Farewell to Kay – and see photos and video from the release at Gordons Bay.

Stay in touch: for daily Aquarium updates, follow us on Twitter (@2OceansAquarium) and become a fan on Facebook.

blog comments powered by Disqus