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Truckee (California), May 17, 2018. A new study published in the journal Endangered Species Research has revealed that juvenile whale sharks swim to Madagascar, a newly-identified hotspot for these huge fish, to feed. Eighty-five individual sharks were identified in a single season using photographs of their distinctive spot patterns.
An isolated ‘island continent’, famed for animals and plants that exist nowhere else in the world, Madagascar’s nutrient-rich waters are also home to an incredible array of marine life attracting increasing numbers of tourists.
Whale sharks are primarily seen around the small island of Nosy Be, in northwest Madagascar. This area is a globally important hotspot for large marine species, including manta rays, sea turtles, humpback whales and even rare Omura’s whales.
The study is part of the Madagascar Whale Shark Project, a collaboration initiated in 2016 by researchers from the Marine Megafauna Foundation, Florida International University, and Mada Megafauna.
Lead author and project leader Stella Diamant said: “We’ve found that whale sharks regularly visit Nosy Be between September and December. That has led to a growing ecotourism industry, as people travel to see and swim with these gigantic, harmless sharks. We’re still learning about their population structure and movement patterns, but it’s clear the area is an important hotspot for the species.”
Whale sharks are the largest fish in the world, growing up to 20 meters long. However, all of the sharks seen in Madagascar have been juveniles of less than nine meters.
“We identified 85 individual whale sharks over our first season in 2016. Some of the sharks were present across several months. They spend a lot of time in the area and seem to come here to feed,” Diamant said.
The marine biologists uploaded photographs of the sharks’ unique spot patterns to Wildbook for Whale Sharks (a global database of sightings) and compared them with data collected from known feeding areas in the Indian Ocean, including Djibouti, the Maldives, Mozambique, Seychelles and Tanzania, but found no overlap.
“Whale sharks are a globally endangered species due to overfishing, accidental catches and boat strikes. Major declines in sightings have been seen in Mozambique, where we’ve documented a 79% decline in sightings since 2005, and the Seychelles. I was hoping that some of those sharks might have shifted over to Madagascar”, said co-author Dr Simon Pierce, co-founder and principal scientist at the Marine Megafauna Foundation.
“Unfortunately, that doesn’t seem to be the case. It’s great news for Madagascar though. These sharks can be a major asset for the country. There’s already a good marine ecotourism industry developing”, he added.
As part of this study, the team attached eight satellite tags to immature whale sharks to track their movements in near real-time. They found that the sharks spent most of their time in shallow waters between 27.5-30°C around the tagging area in Nosy Be.
Half of the tagged sharks also visited a second hotspot near Pointe d’Analalava, 180 km south of Nosy Be. Five of the sharks swam over to Mayotte and the Comoros islands, and two swam right down to the southern end of Madagascar. One of those sharks then swam back to Nosy Be, a total track of 4,275 km.
The sharks are slow-swimmers, travelling an average 21 km per day. Three sharks were resighted in the Nosy Be area the following season after having lost their tags.
“It was exciting to see that there is a second hotspot for the sharks in the area. We will be exploring the area later this year. Madagascar clearly provides an important seasonal habitat for these young whale sharks, so we need to ensure they are effectively protected in the country”, concluded Diamant.
Madagascar is a known location for shark fishing and finning. Whale sharks are currently afforded no formal protection except in two Marine Protected Areas located to the southwest and northeast of Nosy Be.
“Over the last decade, shark populations have declined dramatically in Madagascar due to overfishing. However, the most significant threat to this species is the incidental catch in coastal gillnets and industrial purse seiners operating offshore”, said Dr Jeremy J Kiszka, a marine biologist at Florida International University and co-scientific lead of the Madagascar Whale Shark Project.
Whale sharks are listed as ‘endangered’ on the IUCN Red List of Threatened Species since 2016 and received an Appendix I listing the UN Convention on Migratory Species in 2017. As a signatory to the Convention, Madagascar is obligated to protect the sharks and their migratory habitat in national waters.
The study was supported by Les Baleines Rand’eau, Aqua-Firma, PADI Foundation, IDEA WILD, Waterlust, the Shark Foundation, and two private trusts.
Stella Diamant, Christoph A Rohner, Jeremy J Kiszka, et al. ‘Movements and habitat use of satellite-tagged whale sharks off western Madagascar’ is published on 17 May 2018 and is be available here.
Notes to Editors:
For questions about this study, please contact:
Stella Diamant, Founder, The Madagascar Whale Shark Project
To request a pdf copy of the study and/or high-resolution images, please contact:
Sabrina Weiss, Press Officer, Marine Megafauna Foundation
Email: email@example.com, Tel: +44 7784 659 105
The Madagascar Whale Shark Project is a collaborative research and conservation project between Mada Megafauna, Florida International University, Marine Megafauna Foundation, and the National Center for Oceanographic Research (CNRO), which was launched in 2016 with the aim to study the whale shark population found in the Nosy Be area in order to inform necessary conservation measures. The project is collaborating with local operator Les Baleines Rand’eau, a local ecotourism operator. madagascarwhalesharks.org
The Marine Megafauna Foundation was created in 2009 to research, protect and conserve the populations of threatened marine megafauna around the world. ‘Megafauna’ are large marine species such as sharks, rays, marine mammals and sea turtles. For further details, please see marinemegafauna.org or follow us on Twitter and Instagram. For information about regional projects, follow the Marine Megafauna Foundation’s Western Indian Ocean Facebook page.
Since 2015, the Madagascar Whale Shark Project has been collecting data on whale sharks in Nosy Be. The aim being to understand the ecology, behaviour and conservation issues that whale sharks face in the Nosy Be area.
Here are our key numbers for the 2017 season:
-93 survey days
-1113 bait balls of mackerel tuna/bonito recorded with 40.7% whale shark presence
-342 photo-identified encounters with whale sharks
-105 individuals, 20 females and 85 males.
-33 of these sharks were already present in our database like Michel, Ernest, Théodore, Ignace…
-72 newly-identified sharks like Sirius, Elina, Brigitte, Tristan, Willy…
-5.2m TL is the mean size
– 20 encounters with Michel
-240 sharks identified since 2015!
An epic season! In conclusion, whale sharks seem to use the same area of the bay through the local whale shark season (September to December) across years, building on the results of our 2016/17 satellite-tagging study (Diamant et al. In review). Still none of the 240 immature Nosy Be sharks have been identified from surrounding countries (based on the global database at www.whaleshark.org), suggesting a lack of regular connectivity between the sharks at Nosy Be and other known coastal aggregations in the WIO, such as in the Seychelles, Mozambique and Tanzania. This also indicates that the sharks may be transient to the Nosy Be area, and are only visiting at certain times of their lives, possibly to stock up on nutritious food before heading out into the open ocean once they reach bigger sizes.
A big thank you to everyone who contributed to this year’s data collection:
Arthur et Tanguy Guillemain d’Echon, Elina Sourisseau, Juliet Cussaguet, Mathieu Le Peru, Thomas Quehen, Vincent Quiquempois, Joshua Rambahiniarison, Kelly Morvan, Carole Perrin, Stéphanie Floirat, Arnault de Peretti, Mylène Richard, Guillaume Bonnaud, Michaël Coconi, Salvatore Cerchio, Fanja Andrianarisoa, David Robinson, Simone Caprodossi, Olivier Collinet, Barbara Bini, Jacques Vieira, David Goy, Benoît Raoul, Juliet Cussaguet, Mathieu Le Peru, Cédric Penti, JB Galvès, Corinne Robert, Maxime Brogniart, Norman Guichard, Simon Miller.
All data, photos and figures are the exclusive property of the Madagascar Whale Shark Project, unless stated otherwise, and are not to be copied or reproduced in any manner without authorization from the authors.
The end of field seasons always bears a bittersweet feeling, relief mixed with sadness. Here is a summary of the 2017 season…and our favorite pictures.
This season saw a few new developments, which we were eager to test.
The biggest achievement of the season is by far the introduction and implementation of the Code of Conduct. I previously wrote about the reasons behind the urgent need to adopt a code of conduct, and its introduction eventually was accepted by the majority of operators. On certain occasions I decided to visit operators on a one to one basis to further explain why the code of conduct is necessary, and this approach paid off, both on a personal and professional aspect. While we still experience difficulties with one operator in particular, the atmosphere is drastically different on the water, leading to longer encounters with whale sharks, and safer interactions. A big thank you to all the operators who played the game this season!
We also welcomed our first volunteer helpers, as part of a programme that we developed together with our partners at MADA Megafauna. We welcomed a total of 7 people, who were trained by myself and joined our friends at Baleines Rand’eau daily on the water. The idea behind the programme was to offer a unique experience by providing guaranteed trips at sea, in addition to scientific training so that volunteers would eventually be acting as scientists while on the water and collect extra data when possible. The programme prove to be a huge success, and has more than doubled the amount of data our core research team, comprised of myself and a research assistant, would usually collect. We met a variety of characters and personalities, and are forever thankful for the efforts, energy and commitment of our volunteers! A big thank you Kelly, Carole, Fanny, Arnault, Michael, Mylène and Guillaume! We also welcomed project supervisors Dr. Simon Pierce and Dr. Jeremy Kiszka, guests Hanli Prinsloo, journalists from various TV channels…
Thanks to wider efforts this year, with up to 7 boats per day during peak season, our team managed to record a whooping 327 encounters, which amounts to 107 different individuals passing through the waters of Nosy Be this season! Of these individuals, I recognised about a quarter (final numbers are currently being processed), meaning the area is witnessing a high turnover rate between seasons. Our beloved Michel is still around, as well as regulars Cléandre, Clasperfin, Ernest and Théodore, for example, who we know since 2015. Newbie Sirius possibly might have become the new star of Nosy Be. We were lucky to witness four whale sharks at a time on one day, and pairs of individuals swimming together were often sighted in late November. The presence of females was rare, and only 16 female individuals were identified through the season. We also collected biopsies, and were lucky to witness whale sharks vertical feeding on many occasions (see below, when the shark adopts a vertical position to capture more preys present at the surface).
This season was spectacular in terms of megafauna encounters. Giant oceanic manta rays (Manta birostris) unexpectedly gathered in numbers in both September and December, for a few days at a time, and were found feeding on krill in specific areas, together with smaller mobula rays. Omura’s whales still abound and feed in the waters of Nosy Be from November onwards, and the presence of leatherback turtles was observed during 10 days in November, very probably linked to the high density of jellyfish at that particular time. While the species has been previously seen in Nosy Be, their widespread presence at the surface was definitely a highlight of the season!
Finally, our team managed to find some time to further raise awareness about sharks and our work in Nosy Be. We are looking at widening our efforts to reach more communities on the island after the encouraging results!
It’s been a busy, yet incredible season. I want to personally thank Elina, Juliet, les Baleines Rand’eau, supervisors Simon and Jeremy, the MWSP field team: Vincent, Josh, Kelly, Carole, Fanny, Arnault, Guillaume, Michael and Mylène, project friends David and Simone, Clare, Chris, Sal, Courtney, Jacques, Fanja, Ralph and the team at Senga, for all their help and support. Now back to data analysis and preparing next year’s season! We have also launched eco-friendly clothing merchandise items that you can purchase here.
Again thanks to our funders Lush, Idea Wild, Aqua-Firma, MMF, FIU, MADA Megafauna, Les Baleines Rand’eau for making this work possible.
All photos are property of the Madagascar Whale Shark Project, and were taken by David Robinson or myself.
After meeting with operators and discussing together what guidelines need to be followed in order to ensure better behaviour on the water, minimise the impact on whale sharks and heighten customer satisfaction, Stella delivered 5 training sessions across both Nosy Be and Nosy Komba to present the Code of Conduct, and encourage operators to follow the provided guidelines. The French versions have already been distributed but let us know if you have been forgotten and we will come find you. Already the changes are clearly visible out on the water, with longer encounters with whale sharks, happy clients and a much safer environment for both swimmers and sharks. With less people around, it also is more enjoyable for clients, who can spot and follow the shark more easily. Dr. Simon Pierce, the project co-supervisor, was in Nosy Be recently and he was very happy with the results. We are eagerly awaiting the translated, waterproof copies of the code of conduct to arrive to Nosy Be for the English and Italian speakers, however you can download them already by following these links for English and Italian versions.
So why do we need a code of conduct? Let’s start at the beginning.
Basic facts. Motor boat in the water use propellor engines, that are a risk to any living creature when they are running at any given speed. As a result, both marine creatures, such as whale sharks, and swimmers, are prone to substantial injury, and very possible death, if they come in contact with the propellor. Last year, on a few occasions, clients, guides and our very own team came very close to loosing their heads to engines when ascending from a dive while collecting data on whale sharks as there were more than one boat at a time around a whale shark, and boats moved freely between swimmers. In addition, whale sharks in the area, as well as dolphins and whales, show clear scars resulting from interactions with propellors. Actually, 40% of identified whale sharks in Nosy Be show scars that are very likely due to boat propellors. As the sharks in Nosy Be are all immature individuals too young to reproduce, it is crucial they reach to sexual maturity and survive until they reach a total length of 8.6m.
Another reason is to not bother the sharks. In order to study the impact of boats and swimmers on whale sharks, Pierce et al. 2010 studied avoidance behaviours, such as banking (when the shark shows its back to the swimmer in a defense mechanism), which were shown to be correlated with the number of boats around at the time of the encounter. More boats meant a higher incidence of avoidance behaviours, while these were shown to be less frequent when there were fewer boats around, and when swimmers were relaxed.
Another reason is to enhance customer satisfaction, and provide them with the best possible experience so they will recommend both the place and the operator in the future. Another study by Ziegler et al. 2012, in Mexico, showed that customer satisfaction was directly correlated with longer interactions with whale sharks and less people around, meaning better photography opportunities, less splashing around and a more relaxed whale shark.
Finally, no screaming between operators can only be a good thing, hence why we strongly push for one boat per shark, to reduce a) the risk of propellor accidents to both sharks and humans b) the shark feeling threatened and changing its behaviour c) clients feeling they didn’t see the shark properly or not for long enough and d) tension and chaos between operators. Mostly, adopting the code of conduct will only smoothen interactions while at sea, providing clients a life-changing operators while adopting a respectful approach with both sharks and other operators, even if it means waiting a little bit longer.
The operators that have attended the training sessions and/or discussed the code of conduct with our team are:
-Love Bubble Social Diving
-Scuba Nosy Be
-Nosy Komba Plongée
With the Code of Conduct we hope that operators, clients and whale sharks can safely interact with each other, and give a good impression of Nosy Be and its incredible marine wildlife! Any questions feel free to email us on here.