Monday, 06 April 2009

Pop-up archival satellite tag expedition



SASC, funded by the Save Our Seas Foundation (SOSF), recently returned to the Breede River in an attempt to deploy a pop-up archival satellite tag (PAT tag) on a Zambezi shark. The purpose of this expedition was to deploy a PAT tag and determine where the Breede River Zambezi sharks go in the winter months. PAT tags can collect data such as water depth, temperature and light intensity over a programmed period of time & provide an excellent alternative to time-intensive manual tracking activities using acoustic tags and a hydrophone.

Assisted bya team of professional anglers from Extreme Africa and several commercial fishers, we were hopeful that our attempt to catch and tag another shark would be succesful. Alas, it was not so. After 4 long days of hard fishing - sometimes in near gale force winds - we were unable to catch a Zambi, even though we had several (very) close calls.

Wesley - one of the dedicated anglers - was extremely excited when his 60cm grunter was taken by a large shark who we think, based on additional tracking activities, was Nyami Nyami (see above photo). Alison Kock of the Save Our Seas Shark Centre was also thrilled when, on the third day, the balloon attached to her line with another live grunter began moving quickly across the surface of the river. Unfortunately the shark released the grunter before we were able to reel it in. Judging by the small bite wounds on the grunter, the second shark was a small one - probably 1.5m to 2m in length.

Although we were unable to capture a second shark and deploy our PAT tag, we did manage to find and track Nyami Nyami. We were so excited that she is still in the river - at a time when many Breede River locals had predicted the sharks would have departed the estuary for warmer climes - and that her acoustic tags are still transmitting!

SASC will undertake a return trip to the Breede River to complete this component of the project in the coming months. We are sure the data collected in future from the PAT tag will help unravel some of the mystery behind this species' behaviour in South Africa.

Special thanks to all those who helped out on this expedition, including: the Save Our Seas Foundation, Gavin and Linda Clarke, Lower Breede River Conservancy, Dr. Steve Lamberth & Corne Erasmus (Marine and Coastal Management), Alison Kock, Paul Wildman, Morne Hardenberg, Alison Towner, Eugene Beukes, Danny and the team from Extreme Africa.

7 comments:

  1. I think youn guys are doing excellent work on the Breede. I have been fishing there for some years know and only heard of a shark sighting once. I have been fishing from a kayak laterly and would like to now if its safe enough to do so at the Breede, or sould I stick to a boat or the shore.
    Thanx

    ReplyDelete
  2. Hi Anonymous,

    Thank you for your words of support. As I am sure you are aware, the finding of Nyami Nyami in the Breede has been controversial, and there are many mixed feelings about the study and the presence of Zambi's in the estuary. Hopefully further research will help us all coexist a bit more happily.

    To answer your question: I firmly believe it is safe to say that you should continue to fish from your kayak. The sharks in the river (and yes, there are at least a few) appear fairly disinterested in human activities and something the size of a kayak is probably a bit intimidating to them - definitely bigger than that kob or grunter they are looking for.

    At best, you will be one of the lucky few who get a close-up glimpse of the sharks (given how quiet a kayak can be) and, at worst, you could have one of your fish stolen from your line when you're reeling in.

    I would urge people to keep undertaking those riverine activities they have been engaging in for years - the sharks of the Breede River and the humans sharing their domain have co-existed peacefully for many, many years.

    ReplyDelete
  3. Hi Guys
    Heard that a dog was taken on sunday by a shark at Breede river. Have you heard anything about this. It was taken of the beach near the sand bank, so it must have been at high tide.

    ReplyDelete
  4. Hi Anonymous,

    As far as we are aware, there has been no such incident. We attended the Lower Breede River Conservancy AGM on Easter weekend and heard nothing about this. I am convinced this is just one of many rumours about the Zambezi sharks in the Breede designed to promote public dislike for the species.

    ReplyDelete
  5. The story about the dog was just that, a story. Someone told someone about a dog that was taken by a shark 35 years ago and then the story got told over and over again and the interesting bit of 35 years ago was obviously forgotten to mention, and so the people telling the story just transferred the tragedy from long ago to this Easter. And even I fell for it.

    ReplyDelete
  6. Hi There
    I had the unfortunate experience of capsizing in the mouth of the Breede on 31st October 2009 - I believe the 6th Capsize in the mouth this year - Our Black Cocker Spaniel - Paddy - made front page news by swimming 2km to safety (Google - NSRI Capsize - Paddy)I must say it did cross my mind that he was lucky to avoid some hungry predator

    ReplyDelete
  7. People, dogs and other creatures interact with sharks a lot more than most people would allow themselves to comprehend. Sharks do not instantly attack and kill things just because it is in front of them. Simply put, if this was the case you could never swim anywhere where sharks occurred whether it is the Breede River, False Bay or any other place where sharks and humans utilize the same waters. This just simply isn't the case and it is time we get over this fear which is grossly undeserved.
    Sammy is living proof! and there are many, many more positive shark/human interactions that go unreported as they do not sell papers and are not sensationalized! strange that when sharks interact with us in a non aggressive manner people don't want to know and the media don't want to report it. I just don't get it!
    Sharks are important creatures that should be respected and admired for what they are, predators. They are large carnivores and there is inherent danger when interacting with any large predator. If you want to use the ocean and river systems for recreation then you must respect the fact that large predators require specific areas for their survival. We use the areas for recreation and work, who has the right to be there? the one who needs to survive or the one that "needs" to have fun on the weekend or holidays? I will leave that question with you.

    To d.evans, I am glad you and Sammy survived the capsize, I have been there myself, not a good experience.

    ReplyDelete