News

News from the Bull Shark Tagging Programme will be posted here. Information about my other shark related activities can be found at sharkstudy.org.

17 February 2015

First watch this. And then read "Characterizing the bull shark Carcharhinus leucas habitat in Fiji by the chemical and isotopic compositions of their teeth".

28 January 2014

I am happy to announce the publication of our paper "Long-term changes in species composition and relative abundances of sharks at a provisioning site" in PLoS ONE. Thanks to everybody who contributed to this work!

13 March 2013

I am happy to announce the publication of our paper "Opportunistic visitors: long-term behavioural response of bull sharks to food provisioning in Fiji" in PLoS ONE. Thanks to everybody who contributed to this work!

20 August 2012

This is most exciting bull shark stuff: Christine Testerman from Mahmood‘s lab in Florida has presented the results of her genetic work at the recent meeting of the American Elasmobranch Society in Vancouver, Canada. You can find a copy of the poster here.

It turns out that the Fijian bull sharks are genetically differentiated from the rest of the Indo-Pacific. This is a surprising result and in our opinion most exciting (although not totally unexpected)!

More details to come once the paper is published.

16 April 2012

Bree Tillett and co-authors have published a nice article on bull shark reproductive philopatry in the Journal of Fish Biology. Here is the abstract:

Reproductive philopatry in bull sharks Carcharhinus leucas was investigated by comparing mitochondrial (NADH dehydrogenase subunit 4, 797 base pairs and control region genes 837 base pairs) and nuclear (three microsatellite loci) DNA of juveniles sampled from 13 river systems across northern Australia. High mitochondrial and low microsatellite genetic diversity among juveniles sampled from different rivers (mitochondrial φST = 0·0767, P <0·05; microsatellite FST = −0·0022, P >0·05) supported female reproductive philopatry. Genetic structure was not further influenced by geographic distance (P >0·05) or long-shore barriers to movement (P >0·05). Additionally, results suggest that C. leucas in northern Australia has a long-term effective population size of 11 000–13 000 females and has undergone population bottlenecks and expansions that coincide with the timing of the last ice-ages.

7 October 2011

Ever heard of Isla de Vieques and what the Bull Shark Tagging Programme is doing there? Please go to the Save Our Seas blog to learn more about it!

23 August 2011

For an update on Kirsty please go to my Save Our Seas blog.

16 August 2011

Quite a number of papers on various aspects of bull shark biology and ecology have already been published this year. Check out the bull shark literature page for a listing of these papers.

22 July 2011

For an update on Kirsty please go to my Save Our Seas blog

3 July 2011

It's my pleasure to introduce you to Kirsty Richards. Kirsty will be in Fiji until September to collect data from grey reef, blacktip reef and whitetip reef sharks for her master thesis. I have asked Kirsty to blog about her stay in the South Pacific.

5 May 2011

Back in 2006 we equipped two whale sharks with pop-off satellite tags off the coast of southern Mozambique. One of the sharks lost its tag after only a few days. The other tag was attached for 87 days and that female whale shark not only crossed the Mozambique Channel, but also showed some spectacular deep diving behaviour. On several occasions this shark dived to at least 1287 m while in bathymetrically non-constraining habitat (Brunnschweiler et al. 2009). Now, David Sims and I have taken a closer look at the diving behaviour of this shark while crossing the Mozambique Channel and published the results in the paper "Diel oscillations in whale shark vertical movements associated with meso- and bathypelagic diving" that is currently in press for the book Advances in Fish Tagging and Marking Technology (American Fisheries Society Symposium 76). The time series of swimming depths of this female whale shark was also included in the Nature paper "Environmental context explains Lévy and Brownian movement patterns of marine predators", so this animal has truly delivered some excellent data! Together with my colleague Simon Pierce down in Mozambique we are in the process of satellite tagging two additional whale sharks, so stay tuned for more spectacular news from these fascinating animals!

21 February 2011

Nice video by Ryan Kempster showing a baby bamboo shark exit the egg case at the end of its gestation period. 

18 February 2011

Remember the stomach eversion in a free-living Caribbean reef shark? I documented this extraordinary behaviour in the waters around Walker's Cay in the Bahamas in 2003. And it gets even better! One year later, Frank Nielsen from Sharkfootage.com managed to document stomach eversion in a line-caught shortfin mako!! Needless to say that I was most excited to hear about this; what an opportunity to learn more about the anatomical basis of gastric eversion! Watch it again and marvel at this amazing ability. If you're interested to learn more about the anatomical basis of stomach eversion, read our paper "In situ observation of stomach eversion in a line-caught Shortfin Mako (Isurus oxyrinchus)" in Fisheries Research.

9 February 2011

Good piece by the Pew Environment Group: A review of the current scientific literature on the number of sharks killed per year, the causes of this mortality, the status of shark species worldwide and the impact on ecosystems after large predators are removed.

28 January 2011

Following up on the December post (see below) on recently published papers about shark feeding, I am happy to announce the publication of our paper "Seasonal and long-term changes in relative abundance of bull sharks from a tourist shark feeding site in Fiji" in PLoS ONE. It gives you a good idea about bull shark numbers at the Shark Reef Marine Reserve and provides some baseline data on the long-term trend in relative abundance and seasonal cycle of the species. Thanks to everybody who contributed to this work!

27 January 2011

Check out this multi-media educational shark research interface. Really cool! More about Neil Hammerschlag here.

20 December 2010

Shark feeding remains a hot topic in which the scientific literature is scarce. The debate over baiting sharks for marine tourism is largely based on inference, opinion and anecdote, but very few "hard data" are available. This is one of the reasons why I was delighted to see Aleks' paper "Effects of tourism-related provisioning on the trophic signatures and movement patterns of an apex predator, the Caribbean reef shark" published in the journal Biological Conservation. This is a very fine example of what I believe is a nicely designed and well-performed study. I was much less impressed by another paper recently published in Marine Ecology Progress Series looking at the behavioural response of sicklefin lemon sharks to underwater feeding in the South Pacific. While I acknowledge Eric and his coworkers for bringing science to the controversial topic of shark feeding, I am of the opinion that in this case the presentation and discussion of the results adds more to the debate than to the objectification of the public discourse. Together with my colleague Jon McKenzie we have summarized our concerns in a Comment on Clua et al. (2010) which has been published together with the Reply Comment.

15 December 2010

Check out this info sheet to get an overview of what kind of research projects are going on in and around the Shark Reef Marine Reserve.

6 September 2010

Finally, our paper reporting the results from satellite tagging bull sharks in the Atlantic and South Pacific has been published in the Journal of Fish Biology today: Oceans apart? Short-term movements and behaviour of adult bull sharks Carcharhinus leucas in the Atlantic and Pacific Oceans determined from pop-off satellite archival tagging. Together with the paper from Carlson et al. (see news entry 3 August 2010), these are the first such data available for this species.

13 August 2010

To feed, or not to feed - a fine piece by Doug Seifert; enjoy!

3 August 2010

I was waiting for this paper to be published: Habitat use and movement patterns of bull sharks Carcharhinus leucas determined using pop-up satellite archival tags. On more or less the same day we decided to submit our own paper reporting the results from our satellite-tagged bull sharks in the Atlantic and South Pacific to the Journal of Fish Biology, I received an invitation to review the Carlson et al. paper. I accepted the invitation and found the paper to be very similar to what we produced. I suggested to the Editor of the journal to publish the two papers together in the same issue provided that both papers were accepted for publication by the journal. Both papers eventually made it through the review process, but our own paper took a bit longer to finish and will be published in one of the next issues of the Journal of Fish Biology. Watch this space!   

27 July 2010

Below is a press release from the Save Our Seas Foundation. Check out Andrea's blog if you want to know more about this project.

Dr Andrea Marshall, also known as Queen of the Mantas from the BBC’s 2009 documentary film, has attached a satellite tag to a giant 4 meter manta ray off the coast of South America. This ambassador for Brazilian manta ray conservation is the first manta ray in the Southern Atlantic Ocean to be satellite tagged and another first for Andrea, who originally discovered and tagged this second species of manta ray, Manta birostris, in 2009 in Mozambique.

The tagging is a fundamental part of a comparative worldwide research campaign called ‘Ray of Hope’ funded by the Save Our Seas Foundation (SOSF) and conducted by the Marine Megafauna Foundation (MMF), which is investigating the behaviour and movement patterns of the newly-described giant manta ray. Andrea and colleagues Dr. Simon Pierce and Dr. Juerg Brunnschweiler are travelling to several locations across the globe, teaming up with local researchers or dive operators along the way to locate these mysterious and severely understudied mantas. In Brazil Andrea is collaborating with the Laje Viva Institute and researchers from their ‘Mantas of Brazil’ project.

“This achievement is a piece of manta research history but more than that it is the start of my collaborative work in South America on this species which is currently the only research being conducted on manta rays in the southern Atlantic Ocean. It is a really important step in trying to understand how this species uses the coastline of Brazil, if it travels distances offshore, where their seasonal movements take them and what threats they face on their journeys,” said Andrea.

The tag was deployed last week on a large mature male at Laje de Santos, the largest documented aggregation site for the Manta birostris species in the Southern Atlantic Ocean, and is programmed to stay on the manta ray for 180 days. For the next six months the tag will accompany the manta on its journey through the oceans, functioning like a mini-lab and storing data critical to the investigation. As well as recording the water temperature through which the manta swims and the depths the animal reaches, it also records the light levels and its GPS position every time it breaks the surface, information used in determining the individual’s actual track.

Almost nothing is known about the lives of manta rays in South America and Andrea hopes the study will help answer a series of questions aimed at providing invaluable information for managing the region’s manta ray population and better protecting them from fishing pressure and other human induced threats such as shipping traffic. “As we continue to learn more about these ocean giants, I also continue to learn and grow as a scientist. Patience is an important skill in field research as is the determination to see difficult projects through to completion. In the end, persistence will pay off, and although we sometimes feel that we are racing against time, we are ultimately at the mercy of the animals that we study and the elements of nature. Sometimes sitting back and waiting for them to come to us is the only solution,” said Andrea.

23 July 2010

Diving in the Shark Reef Marine Reserve is different from most other places foremost because of the number of sharks. Their presence somewhat distracts from focussing on the smaller creatures that live on the reef. And there are plenty of them! For example, tiny little juvenile sharksuckers that are looking for a host or already found one. Very little is known about the behaviour and ecology of sharksuckers generally and even less about their juveniles. Ivan and I have now added some information: Swift simming reef fish as hosts for small juvenile sharksuckers. Let me know if you need a PDF copy of it.

14 June 2010

I have been part of an international research team led by David Sims from the Marine Biological Association Laboratory in Plymouth and it is with great pleasure that I announce the publication of our paper "Environmental context explains Lévy and Brownian movement patterns of marine predators" in Nature.

18 May 2010

It is with great pleasure that I announce the publication of our paper Using local ecological knowledge to identify shark river habitats in Fiji (South Pacific). It reports the first results from our work in Fijian rivers. There is more to come in the future, so watch this space.

30 March 2010

I have added the footage of a blacktip shark jumping out of the water and a Caribbean reef shark everting its stomach to Vimeo.

25 March 2010

There are two things I like to share with you today. First, have a look at Sharks and Their Relatives II. Quoting from the Summary: "Since the award-winning first volume, The Biology of Sharks and Their Relatives, published in 2004, the field has witnessed tremendous developments in research, rapid advances in technology, and the emergence of new investigators beginning to explore issues of biodiversity, distribution, physiology, and ecology in ways that eluded more traditional studies". No doubt, this is very essential reading!
Then, check out fish2fork. Such initiatives are excellent. For example, check out what they say about the Nobu in NYC (and London). There is just no way you can (and should) eat bluefin tuna!

16 March 2010

Here is a nice clip from Fiji that forms part of Fragile Paradise, a contribution to South Pacific by the BBC.

1 February 2010

I have added a page that lists scientific papers dealing with bull shark biology and ecology. I will update the list as soon as new papers become available, so those of you interested in bull sharks can stay up to date with what is known about this species. If you want a PDF copy of one of the papers listed, please email me.