BRONZE WHALER SHARK NECROPSY
May 19, 2019 Dyer Island Conservation Trust
On the morning of Thursday the 16th of May, the Dyer Island Conservation Trust team and Marine Dynamics Acadamy intern Jade Sookhoo conducted a necropsy at the International Marine Volunteer Lodge on a prenatal bronze whaler shark (Carcharhinus brachyurus). This shark was part of a litter of 12 pups collected from a pregnant female bronze whaler that was found stranded on De Plaat on the 5th of March, 2019. (See link to previous DICT blog on discovery and collection).
The necropsy was performed in the presence of a group of learners from Gansbaai Academia, as part of their Marine Science curriculum, together with teacher Lizelle Carolus and Xavier Zylstra from Two Oceans Aquarium.
The necropsy process is a lengthy one, even for a specimen so small, and starts with an extensive array of external examination including a large collection of measurements of size and form before the first incision is made. This quantitative data is of great importance as it can reveal many things to us and be used to support and complement the classic taxonomic identification or reveal a new species when discrepancies are discovered in these measurements.
This was the first time DICT examined a prenatal specimen. The female pup, which was in the later stages of development, measured a total length of 67.5cm and weighed in at 1.85kgs. Bronze whalers reproduce viviparously: just like humans the embryo is attached to a placenta by an umbilical cord, and is still dependent on nutrients from the mother. As a result of this, the stomach was still empty, and the spiral valve lacked their signature folds.
The gestation period of bronze whalers is still uncertain, but research suggests the female carries the pups for a duration of approximately 12 to 21 months. Based on the development of the pup, we think she was perhaps weeks away from being born.
The Dyer Island Conservation Trust collaborates with various researchers around the country and value the sharing of data to further expand our knowledge base. Apart from collecting fin-clipping samples for genetic analysis, we also isolated both gill-sets for parasite analysis, and the whole head for a project that analyses the neurological network of sharks.
During the necropsy, the learners from Gansbaai Academia asked our scientists loads of questions about sharks, and they learned a lot about why we do these measurements, about shark physiology, and how sharks work internally.
A special thanks to Janine Taylor, Anthony Fouche and Marcelino Henckert for reporting original stranding of the sharks and to the Marine Science programme team at Gansbaai Academia for being part of the necropsy.
RECYCLING DAY 2019
May 17, 2019 Dyer Island Conservation Trust
International Recycling Day was created in 2018 to help recognize, and celebrate, the importance recycling plays in preserving our precious primary resources and securing the future of our planet. The theme of 2019 was ‘Recycling into the Future’ with the aim of driving awareness and pushing the urgency of recycling. Recycling (whether at an industrial level or within schools and home) can save more Carbon Dioxide emissions each year than those generated by the entire aviation industry, while simultaneously protecting the earth’s valuable natural resources.
Recycling Day is used as a catalyst to change the mind-set of governments, businesses, communities and individuals around the world, to see recyclables as a resource and not waste. Without recycling, all our used and discarded tins, plastic bottles, packing boxes, old clothes, glass bottles and paper cups will contribute to the growing waste mountains, which are either burnt or sent to landfill – never to be used again. Without recycling, we have no option but to continue stripping the earth of her resources.
The Dyer Island Conservation Trust’s Environmental Education Programme known as DEEP has taken an initiative to celebrate recycling day by hosting a Trashion Show at Masakhane Primary School to show that we can turn Trash into Treasure. This show was attended by the community members, Marine Dynamics and Dyer Island Cruises staff and the Masakhane learners and teachers.
DOLPHIN DEATH TRAP REMOVED FROM RICHARDS BAY
April 29, 2019 Dyer Island Conservation Trust
The Dyer Island Conservation Trust team is excited to hear this good news with regards to the lifting of a shark net in Richards Bay (Kwazulu-Natal), to better protect the endangered Humpback dolphins. Well done to marine biologist Shanan Atkins and the team that worked on this. It’s a much needed step forward in finding alternatives to bather protection shark nets. The Dyer Island Conservation Trust is part of the SouSA Consortium and has been studying the humpback dolphin population in the Kleinbaai (Western Cape) area for over a decade. We hope that with positive steps forward like this that our sharks will ultimately be afforded the same protection.
"The shark net that kills the most endangered humpback dolphins has recently been removed. This net was protecting the often-empty “inside” beach at Richards Bay, KwaZulu-Natal, where many more dolphins were caught than potentially dangerous sharks. The KwaZulu-Natal Sharks Board has replaced the offending shark net with four baited hooks (drumlines).
Humpback dolphins are endangered because they are rare, they reproduce slowly and only occur in a narrow band of very shallow coastal waters, close to shore - an area that is fast being modified and degraded. In KwaZulu-Natal, the best place to find these shy dolphins is on the Thukela Bank, a shallow shelf that juts out between the Thukela River and St Lucia. Research has revealed Richards Bay is a hotspot for humpback dolphins – an area that is popular with the dolphins but overlaps with many human-induced threats. A major threat is the shark nets.
Shark nets are gillnets set to catch and kill sharks, to lower the population of sharks in order to reduce the risk of shark attack. In addition to the three species of sharks that are targeted by these nets, other non-target species are caught and killed, including dolphins. These unfortunate, unintentional catches are called bycatch. In KwaZulu-Natal, there are 37 beaches that have shark nets. One beach, Richards Bay, has by far the greatest bycatch of humpback dolphins (60% of the humpback dolphin bycatch in just 5% of the province’s shark nets).
Since 2010, 26 humpback dolphins have died in the six shark nets at Richards Bay. Conservation biologists from the project Conserve Dolphins, working in partnership with the KwaZulu-Natal Sharks Board, analysed the spatial distribution of the bycatch and found that nearly half of these deaths occurred in just one of the nets – “net 99”. Over the same period, net 99 caught a single target shark. The scientists went on to study how often people surf and swim at the Richards Bay beaches. Results indicated that Newark Beach which is protected by net 99 (called “the inside beach” by locals) is used only rarely, on average less than 10 times per month.
At the beginning of April, the KwaZulu-Natal Sharks Board replaced this net with four baited hooks (commonly known as drumlines). Drumlines have been widely used in KZN since 2007 without compromising bather safety (and in Queensland, Australia since 1962). They work on the same principle as the shark nets; killing sharks to reduce the chance of a shark attack, but on the positive side, they catch fewer non-target species. Says Greg Thompson, Head of Operations at the Sharks Board: “Drumlines have proved invaluable in providing protection against shark-inflicted injury along the KwaZulu-Natal coast, catching potentially dangerous sharks, but with very little bycatch of dolphins, rays, turtles and harmless sharks.” One net on Alkantstrand’s main beach was also replaced with baited hooks and in total there are now four nets and nine baited hooks protecting bathers at Richards Bay.
The deaths of 26 dolphins in nine years may not sound a lot, but given how rare these dolphins are, and how slowly they breed, that mortality rate is unlikely to be sustainable. Net 99 alone killed an average of 1.2 dolphins per year. Therefore, removing it could reduce the bycatch by a third and potentially saves one humpback dolphin life each year. That is a significant saving. "Considering bycatch is one of the main threats to the endangered humpback dolphin in South Africa, this is a huge step forward in the right direction to ensure the species' long-term survival and well-being in our waters!" observes Dr Els Vermeulen of the SouSA Consortium. The SouSA Consortium is a group of 16 dolphin researchers stationed around South Africa’s coast that have teamed up to study humpback dolphins (Sousa plumbea) at a national level.
Local citizen scientist and dolphin enthusiast, Dave Savides, is a regular at Richards Bay’s Dolphin Viewing Platform where he photographs humpback dolphins for the project Conserve Dolphins. In the past he witnessed one of those 11 dead humpback dolphins being retrieved from net 99. He confesses: “It is such a relief to look out and see these graceful creatures feeding and playing and not have to worry that one might get caught and drown in that awful shark net.”
A webcam looks out over this area and humpback dolphins can sometimes be seen. This live view of the Richards Bay beaches can be found at www.dolphins.org.za . Viewers are encouraged to report dolphin sightings via the webpage."
PENTHOUSES FOR PENGUINS
April 16, 2019 Dyer Island Conservation Trust
Why are we designing the perfect artificial African penguin nest?
Before the advent of artificially produced fertiliser, guano was considered a top quality fertiliser rich in nitrogen, phosphorous and
potassium. Guano (an Inca word for a mix of eggshell, feathers, decayed corpses and bird excrement) was scraped from the penguin breeding islands. On Dyer Island, the guano layer was between 4-6m deep. Penguins used to build their nests by burrowing into the thick layers of guano. This “forced removal” from well protected, temperature controlled burrows to open surface nests, exposed the African Penguin to the harsh African heat and occasional flooding. The “open-plan” living arrangement turned their eggs and chicks into an easy meal for predators like gulls & skuas.
At the start of the nest / housing project in 2006, the main aim of the artificial nests was to provide protection from predation. The original nests were manufactured from fibre-glass and although the nests addressed the predation problem, research indicated that the nests became too hot inside. Penguins simply abandoned the nest leaving eggs and chicks behind.
Meeting the housing needs of the African penguin started us on the quest for the perfect penguin penthouse. Research told us that the guano burrows provided the penguins with:
• A constant micro-climate
• High relative humidity
• Buffered temperatures
• Little exposure to the wind
• Shelter from rain & predation
GREAT WHITE SHARKS SWIM THROUGH KELP
April 03, 2019 OLIVER JEWELL
It’s been more than five years since I moved my life from Gansbaai and the Dyer Island Conservation Trust, first to Europe and then Australia, which I still find incredible to believe… how time flies… But I remain an associate researcher with the Trust and Marine Dynamics and I’m proud to announce our latest paper in collaboration between the Centre for Sustainable Aquatic Ecosystems, Murdoch University, Monterey Bay Aquarium’s Conservation Research Team and Hopkins Marine Station, Stanford University has just been released in Biology Letters. In 2014, we launched a research expedition to the very same areas I’d spent many hours of my life tracking white sharks or guiding for Marine Dynamics Shark Tours around Dyer Island. We had already discovered this region hosted the largest aggregation of white sharks in the world, that they used small areas around the island when foraging, performed two distinct predatory behavioural modes and that in response to the presence of white sharks, seals would use kelp forest as a refuge. What we didn’t know is quite how all these interactions played out underwater.
Cue fin-cams! Or more specifically Animal-borne video and environmental data collection systems (AVEDs for short). These are specially designed tags which include ‘daily-diaries’ similar to Fitbits that log the movements of the animals in three-dimensions while the camera allows us to see what the shark does.read more
DYER ISLAND CONSERVATION TRUST LOOKS AT THE BIGGER PICTURE AND THE JOURNEY AHEAD
April 03, 2019 Dyer Island Conservation Trust
Tourism partners, friends, and media, gathered at an evening event with the team of Dyer Island Conservation Trust and Marine Dynamics to look back at nearly two decades of research, conservation and education achievements.
Our marine environment is under immense pressure and over the last two decades that Marine Dynamics and Dyer Island Cruises have been in operation, we have been witness to it. Throughout our dedicated work, we continually identify gaps in marine conservation, science, and awareness in their area.
The Dyer Island ecosystem is a complex and incredibly diverse habitat supporting the Marine Big 5 – sharks, whales, dolphins, seals and the endangered African penguin. We are a team of dedicated biologists, expert support crew, a dive team, and volunteers from all corners of the planet. Driven by a sense of purpose and responsibility the team’s greatest role every day is to ensure a positive interactive experience, monitor marine species and educate guests. The daily observational data from the eco-tourism vessels is critical and plays a large role in monitoring of species and forms the basis for our scientific publications. Scientific evidence is imperative to being able to influence policy decisions. We have 18 years of consistently collected observations from Dyer Island Cruises and 14 years from Marine Dynamics some of the world’s most extensive databases that exist for Southern African marine species.
The question of whether tourism does enough to conserve the wild habitat and species upon which their experiences are based, has been raised. Owner and founder of Marine Dynamics and the Dyer Island Conservation Trust spreads the message that “Your Choice Makes a Difference’ encouraging tour operators and travellers that choosing ethical operators is a way of giving back and ensuring your spending contributes to so much more.
Our key message was that even though we may be in a small part of the world, much can be achieved on a global level, with a dedicated team. Past achievements of conservation for the white shark and endangered African penguin were shared. The team also does Baited Remote Underwater Video (BRUV) studies, estuary monitoring, tagging of smaller shark species, seabird monitoring, shark egg collection – all in efforts to understand and protect this delicate ecosystem. “HOPE, ACTION and URGENCY will continue to drive our conservation and community work. We use events like this to spread the word and to effect change. Change becomes reality when people are informed about issues,” said Chivell. “We hosted the auction and raffle to add some fun to the event and were grateful to raise R28 500 which will support the efforts of the Trust. None of our work is possible without the support of our private and corporate donors, and the invaluable support of our conservation partners and the tourism industry.”
The event was held at the Two Oceans Aquarium who very kindly sponsored the venue in their incredible new predator exhibit room. Liezel van der Westhuizen was the MC and made sure to keep the audience entertained with her amazing energy and clear passion for marine conservation. The auctioneer MC du Toit made the bidding on items very entertaining and upbeat, sparking lots of laughs from the guests. So many people came together to help us have a great evening sharing our conservation journey with our travel partners, media, and friends.
Special Thanks to:
Two Oceans Aquarium
Marine Dynamics & Dyer Island Cruises
Liezel van der Westhuizen
MC du Toit - BidX1
Martinus van Tee Illustration
Worldwide Experience – Pearl Valley Hotel
Village & Life – Pezulu Hotel
Misty Waves Hermanus & La Pentola Restaurant
Luxury Safaris Southern Africa & PG Tops
Cape Side Car Adventures
Cape Food & Wine Tours – Earthstompers
Aquila Private Game Reserve
Village & Life - Bay Hotel
Van Loveren Family Vineyards
Old Road Wine Co.
Lomond Wine Estate
DEEP AT THE REFOREST FEST
March 20, 2019 Dyer Island Conservation Trust
The 2019 intake of the Dyer Island Conservation Trust’s Environmental Education Programme (DEEP), joined Greenpop’s Treevolution Reforest Festival this weekend in Platbos. This was an Eco-friendly, Zero Waste event for families to rebuild this indigenous ancient forest. It was a weekend filled with fun activities, puppet shows, forest walks, talent show and music and a platform to educate people about the importance of trees. Over 500 people attended this camp and ±2000 trees were planted on Saturday. “The DEEP kids enjoyed themselves and loved the tents. This was their first time camping. They had the opportunity to mingle with other children from different schools and to experience vegetarian meals. Special thanks to Wilfred Chivell and the staff of Marine Dynamics for the support of this outing,” said Trust educator, Pinkey Ngewu.
PENGUIN PICTURE HAS THE PERFECT HOME
March 19, 2019 Dyer Island Conservation Trust
In 2018, our penguin philanthropist, Mike Gibbs, kindly donated a special drawing of African penguins by Hermanus artist Malcolm Bowling. This picture went on silent auction at the African Penguin and Seabird Sanctuary (APSS). It finally has a home - with the Kendziorski family. The Kendziorski’s are from the USA and have been volunteering their time at APSS while in South Africa. Alex, Rebecca and their son Liam, were very excited to take this picture home. They are previous donors to the sanctuary and the APSS team is grateful for their generous R8500 donation for this iconic image of rehabilitated penguins.
The Kendziorski’s had the following to say, “We are grateful that we can participate in one of the last chances to prevent the extinction of the African penguin. Working with the birds directly has also been a joy as well as inspiring. Seeing how our donations are put to use in person has given us great confidence in our continued support. We can all be part of the change needed to save the penguins. Reducing the use of plastics, shoreline clean-ups, and learning and sharing information about what actions you are doing to help prevent their extinction. We are better together.”read more
Great White Sharks Tagged in Gansbaai
March 15, 2019 Dyer Island Conservation Trust
“We are thrilled to have acoustic tagged two Great White Sharks from our research boat today!”, said shark biologist Alison Towner. It’s been over two years since a transmitter (tag) has been deployed on a white shark in Southern African waters largely due to their unpredictable distribution patterns, and a notable decline in white sharks visiting two Western Cape aggregation sites.
DEAD BRONZE WHALER SHARKS, GANSBAAI
March 07, 2019 Dyer Island Conservation Trust
On Tuesday the 5th March at 9 am, Anthony Fouche of Gansbaai documented the carcasses of eight large bronze whaler sharks at Die Plaat, Gansbaai. The Dyer Island Conservation Trust (DICT) / Marine Dynamics team were notified in the late afternoon and made their way down to the site to collect them.
On arrival, the team found three of the eight dead sharks. It is assumed that the rest were taken away to be sold, as the bronze whaler is a commercially fished species. Even though bronze whalers are generally regarded as low value there is a market for both their meat and fins for export in South Africa. Of the three shark carcasses left on the beach, the DICT team were able to confirm that all were reproductively mature, measuring around 3 meters each. One was a heavily pregnant female with the tail of a pup expelled from her cloaca. The team removed the pup and decided to open the mother shark to attempt to save any other remaining pups. Another 13 full grown shark pups were found, likely just days away from birth, but unfortunately all the pups were deceased due to the extent of time the shark had been dead. Bronze whaler sharks do not reach maturity until approx. 20 years old and this information is important as it supports the fact that the Walker Bay waters, similar to False Bay, are being utilised as feeding areas for pregnant sharks and even possibly a nursery area for this IUCN near threatened species. Another pregnant female carcass washed up in Walker Bay on the morning of the 7th.read more