Gansbaai: International Coastal Clean-up Day

September 18, 2017 Dyer Island Conservation Trust

Annually, the world unites in a coastal clean-up initiative. Data collected from this day feeds into a national and international database with Ocean Conservancy who started this global action.

This year the Dyer Island Conservation Trust partnered with Volkswagen, Marine Dynamics and Overstrand Municipality in support of International Coastal Clean Up Day. In Gansbaai, a few groups united to work in different areas. Our group of 39 including our environmental education group (DEEP) tackled the Gansbaai caravan park area, moving towards the Gansbaai tidal pool, a distance of 1.5km. Together we collected 21 bags of trash totalling 55kgs. The primary items we collected were condoms (152), straws/stirrers (892) and plastic bottle caps (554). Other high items were cigarette butts (340) and food wrappers (314). These findings are consistent with international stats on prime marine pollution offenders.  The condom problem is along our valuable coastline and is a direct action of the illegal abalone poaching in the area. It is believed the condoms are used to keep cell phones protected.

read more

The Tooth, the Whole Tooth and Nothing but the Tooth

August 28, 2017 Georgia French

Background

In late 2014 and early to mid 2015, I was lucky enough to collect data on white sharks with the Dyer Island Conservation Trust (DICT) and Marine Dynamics (MD). I’m working on my PhD with the University of Sussex, focussing on sexual and individual variation in white shark ecology. I’m very pleased that the first chapter of my PhD has just been published as a paper in the Journal of Fish Biology.

This paper is all about the white shark’s famous teeth, and how they change shape as they get older. Kind of like in humans, smaller white sharks are thought to have “baby teeth” – pointy in shape, which is believed to be an adaptation for gripping fish prey. When the sharks hit roughly 3m in length, they’re then thought to get their “adult teeth” which are broad in shape and believed to facilitate catching and eating marine mammals like seals and dolphins. This change in tooth shape is taken as established fact, and is accepted and quoted around the world. However, through reading several books and papers I’d found a few pieces of evidence that seemed to show that this wasn’t always the case, so I decided to look into it further.

Data Collection

The first challenge was to figure out how to get measurements of the teeth. All of the previously published work on white shark teeth was from dead sharks – I needed to come up with a method to get the same measurements from live ones. This is where DICT and MD came in. I realised that cage diving provides the perfect opportunity to get good photos of the shark’s teeth – if you look through the MD blog, you’ll see what I mean! When the sharks interact with the seal decoy or bait lure, they often either treat them like prey, or they try to check them out with their mouths (as they are lacking in the hand department, they use their mouths to see what things feel and taste like). This means that they open their mouths a lot – perfect.

I designed a method that meant that I could calculate how “pointy” the shark’s teeth were from photographs taken during cage diving trips. Being able to work from Slashfin was a huge bonus, as it’s very stable and comfortable, and has a nice high viewing deck that meant myself and colleagues could get photos from above, as the sharks came out of the water. In addition to the tooth photos, from Slashfin it was possible to estimate each shark’s length, see if it was male or female, and identify each individual so that I would know if I had measured its teeth twice. I then combined these data with published information and measurements taken from the jaw collection of the KwaZulu-Natal Sharks Board and analysed the relationships between male and female shark length and their tooth shape. The findings were pretty astounding.

Results

It turns out that it seems like the males and females are very different when it comes to their teeth. The main results showed that male sharks do change their teeth from pointy to broad, but females don’t. In the females, I identified three different tooth shapes – pointed, intermediate and broad – and a female of any size could fit one of these categories. This suggests that there may be three “types” or morphs of female, which could be specialising on different types. Alternatively, tooth shape could actually have nothing to do with diet, and instead males could be using their broad teeth to help them hold onto females during mating. Both of these scenarios blow the classic concept of tooth shape change through a white shark’s life out of the water.

Experience and Thanks

During data collection, it was great to be able to talk to interested clients about what I was doing, and to spend time in the company of the most awesome fish in the sea was just fantastic. I was really grateful to all of the crew of Slashfin, who skilfully brought the sharks to the boat, helped me to accurately estimate the shark’s lengths and sexes and identified individual sharks that they knew.

It was also an absolute pleasure to give talks to and work with groups from International Marine Volunteers, who got valuable experience in white shark research through MD and DICT. One of these volunteers, Richard Dolan, is actually a co-author on the tooth paper as he volunteered to help individually identify the sharks in my dataset using DARWIN fin ID software – the same technique used previously by DICT scientists to make the first population estimate for white sharks in South Africa using photo ID. In fact, DICT associate David Edwards, who managed the DARWIN database for that paper, is another co-author on this research as he also helped out massively with my DARWIN work.

I’m hugely thankful to Onno Keller and Kelly Baker, MD Marine Biologists past and present, who in addition to providing me with accurate information on the sharks when we were on the boat, gave me some of their tooth photos from the trips. I also have to mention and thank Reservations Manager Aletta van Bosch for getting me onto the shark trips and of course, Wilfred Chivell, owner of Marine Dynamics and Founder of DICT, without whom none of the fieldwork would have possible.

 

read more

Launch Of ‘NICOLE’ – The True Story of a White Shark's Journey

August 23, 2017 Brenda du Toit

There was a festive atmosphere at the Marine DynamicsPenguin Random House launch of “Nicole” by author Richard Peirce. “Nicole” tells the story of the iconic great white shark that swam 22000kms from South Africa to Australia and back in less than nine months. The book also highlights the plight of white sharks worldwide especially with regards to shark finning.

Richard is a passionate conservationist and headed up the Shark Conservation Society in the UK for many years running a number of expeditions all of which achieved significant successes in securing real conservation measures. Ably supported by his wonderful wife, Jacqui, who takes many of the images you will find in Richard’s books, Richard travels widely and has seen first-hand the impact man is having on the environment and the species that we share this planet with. This drives the stories he films and writes – true stories with some creative licence to attract our attention and make us think differently. Richard always sponsors non-profits through all his books and passed on a third of the night’s sales to the Dyer Island Conservation Trust for white shark research. The Dyer Island Conservation Trust has been operational since 2006 focusing on research, conservation and education initiatives with a special focus on white sharks and the endangered African penguins. Through book sales, a fun raffle and the auction of various items, R27810.00 was raised towards the charity. The evening was enhanced by wine tasting courtesy of Lomond Wine, while Richard signed copies of his books for all the shark enthusiasts. Richard also introduced his upcoming book ‘Cuddle Me, Kill Me’, a harrowing story of the lion trade. This will be released in 2018.

read more

Posing for Penguins

August 09, 2017 Brenda du Toit

There was preening and fluffing of feathers, not at the African Penguin and Seabird Sanctuary (APSS), but for the ten winners of the Pose for Penguins makeover. This fundraising initiative for APSS was the brainchild of Nicolene Richards and Karin Franken and in just a couple of weeks raised an incredible R10 200 thanks to the support of the local Gansbaai residents.

The red carpet was laid out at Hair Style Studio where hairstylists, Natasha van der Berg and Elmarise van Dyk and make-up artists, Amorette Groenewald and Jeanre du Plessis worked their magic. Nicolene and Karin had as much fun styling each individual lady adding splashes of colour courtesy of Komtessa Boutique. Photographs of the before and after were captured by Sanchia Chivell. Food was provided by the Great White House, wine sponsored by Creation Wines, with gifts and Champagne sponsored by the organising duo.

“Fundraising initiatives like this go a huge way in helping the needs of the endangered African Penguin, a species whose survival depends on all of us not just those directly involved in their rescue and rehabilitation.  With an estimated 18 000 breeding pairs left and a possible extinction in the wild by 2030, we have to do everything in our power to turn this around,” said Wilfred Chivell, founder of the Dyer Island Conservation Trust. “A very big thank you for the support of everyone especially the ladies that used their time and talents to create a successful make over day.”

Nicolene Richards supports the sanctuary in various ways and plunged right in to help the penguins, “Karen and I did what we love doing, using our passion for styling to make a difference. We are already planning our next one. Congratulations to all the winners.”

read more

67 Minutes for Mandela Day

July 18, 2017 67 Minutes for Mandela Day

The Marine Dynamics team thinks 67 minutes for Madiba is too short a time to do all the good that needs to be done and so makes it our way of life. When Madiba day comes along, we believe in keeping it local and where best to start than with our DEEP group. The Dyer Island Conservation Trust Environmental Education programme consists of 24 students with some in their second year and others that started their three year programme this year. We thought we would spread the love and organise some food parcels for their families.

We approached SPAR Gansbaai who came on board also donating some shopper bags to use. SPAR has been one of the leading companies promoting the Rethink the Bag campaign in South Africa and as manager of the Gansbaai SPAR said, “This is an awesome opportunity to highlight this campaign encouraging people to discontinue using plastic shopping bags.” The Rethink the Bag campaign was started by Two Oceans Aquarium and is encouraging consumer behaviour change. The Trust’s educator, Pinkey Ngewu, and other members of the team headed out on Tuesday to brighten everyone’s day.

read more

Shark Awareness Day 2017

July 14, 2017 Brenda du Toit

The main purpose of the annual Shark Awareness Day is exactly that – creating awareness of sharks as a critical part of our oceans.  Sharks are a large group of fish that have inhabited the oceans for over 400 million years. There are over 500 species of sharks in the ocean but here at Marine Dynamics and the Dyer Island Conservation Trust, our team deals with one of the most charismatic ones, the great white shark. After four confirmed orca predations on white sharks since May, the sharks had been scarce in Gansbaai but as if knowing there was something special about the 14th July, Marine Dynamics enjoyed a good sighting of a 3m white shark.

While guests were enjoying the sighting, our shark biologist, Alison Towner, was working with the Dyer Island Conservation Trust’s Environmental Education Programme (DEEP). The group in their second year has been able to witness and touch the deceased shark and is learning more about this species throughout the programme. One of the tasks the students are challenged with is to do presentations and on this day eight of them showcased various shark species. Alison was there to encourage them and to share more about sharks.  Some shark cakes rounded off the day as did some champagne for the guests of Marine Dynamics.

Pictures
1.Nicole Schutte with shark biologist, Alison Towner, showing the DEEP students the equipment used in tagging and tracking white sharks
2. 2nd year DEEP student Aphelele Jordaan

read more

Sperm Whale Washes Up In Gansbaai

July 03, 2017 Brenda du Toit

A sperm whale (Physeter macrocephalus) recently washed up in the Pearly Beach area of Gansbaai. As a deep water whale found in most of the world's ocean, they are not often seen close to shore so this carcass provides a rare opportunity for scientific sampling which is what the Marine Dynamics / Dyer Island Conservation Trust (DICT) team arranged. The whale is in a fairly decayed state.

Sperm whales generally measure about 17m but some up to 20m have been recorded. During the days of commercial whaling, sperm whales were caught off both our east and west coasts – they were so named because when the head was cut open it was found to contain a milky white substance, and the whalers thought the large square head was a huge reservoir for sperm. It is in fact spermaceti oil, thought to help in buoyancy control when diving and acts as an acoustic lens. Additionally, an intestinal secretion called ambergris is found in sperm whales which is used in the perfume industry.

“This is the third sperm whale that has washed up in the Gansbaai area in the last four years which is amazing because we don’t know where they come from. We have DNA samples of all three and will have it analysed and see what further information we can find out,” says Wilfred Chivell of DICT.

The sperm whale belongs to the suborder of toothed whales and dolphins (odontocetes) and is one easily identified by its bushy, angular blow as it has a single blowhole right at the front of the head, on the left.  They have between 36-60 conical teeth in their long, narrow lower jaw – in adult males these can grow to 25cm long and weigh 1kg each, although only a third of the tooth appears above the gum. The sperm whale has relatively short, stubby flippers and a low hump instead of a dorsal fin, and triangular tail flukes, which are raised when diving.

The sperm whale is one of the deepest diving mammals in the world. Typically it makes dives of up to 400 m, but can reach depths of up to 2-3km. It is thought to be able to hold its breath for up to two hours, although 45 minutes is the average dive time. Some sperm whales have scars on their bodies caused by rare encounters with feisty giant squid.. Although sperm whales are known to eat a wide variety of sea creatures their major prey items are deep-water squid of less than 3kg in weight. A sperm whale spends most of its life in either 'nursery schools' (adult females with young) or 'bachelor schools' (males between seven and 27 years of age) although older males tend to live on their own or in very small groups and join nursery schools during the breeding season. The only natural predator of the sperm whale is the orca and even then most attacks are not thought to be fatal.

Sperm whales are protected from commercial whaling but modern threats are  ship strikes, injury due to human interactions when they steal fish from longliners, chemical and noise pollution and entanglement in fishing nets, especially ghost gear. The current worldwide population is not known and the conservation status of the sperm whale is listed as Vulnerable (IUCN 2008).

read more

DICT Environmental Programe June Rundown

June 30, 2017 Dyer Island Conservation Trust

June was an eventful month for the DEEP group. On the 8th we celebrated World Oceans Day and Youth day on the 16th of June.

June 08 – World Oceans Day

read more

International Great White Shark Research Team Work With Dyer Island Conservation Trust

June 15, 2017 Brenda du Toit

The Dyer Island Conservation Trust and Marine Dynamics team were recently joined by past Master’s students, Oliver and Michelle Jewell, to continue Oliver’s studies on great white sharks.

Oliver is a PhD candidate affiliated with Murdoch University. Oliver is looking at the foraging and swimming patterns of great white sharks by observing body movements and tail beats using camera loggers attached with a special clamping system. The team included Oliver’s supervisors Dr Adrian Gleiss (Murdoch University) and Dr Taylor Chappell (UC Davis); and a research and film crew from Monterey Bay Aquarium – Dr Salvador Jorgenson, Presley Adamson and Paul Kanive. Further support was given by past employee of the Trust, David ‘Ed’ Edwards and his partner Anna Phillips. Ed assisted with the white shark population study the Trust released in 2013.

read more

Great White Shark vs Orca May 2017

June 08, 2017 Brenda du Toit

May 2017 was an interesting yet trying time for the team of Marine Dynamics and the Dyer Island Conservation Trust who were called out to retrieve three deceased white sharks in a space of a few days – a female of 4,9m and two males at 3,6 and 4,5m. All three sharks have been identified from our extensive database.

Our shark biologists, Alison Towner and Kelly Baker assisted by our team and experts in their field including Dr Malcolm Smale, and with the permission of the Department of Environmental Affairs did the dissections on site in Gansbaai. All three sharks had consistent bite wounds and were found to be missing their livers. This indicates what is known of orca predation on sharks as they attack and stun the shark into tonic immobility and the buoyant liver rises to the surface through the injury. The squalene rich liver is the only part that the orca’s appear interested in although the one male shark was also missing a heart. This is the first time ever that a white shark has been dissected after an orca predation and this is the first official observation in South Africa stunning researchers and shark lovers.

read more