Bull Sharks on Chumphon Pinnacle Thailand

This Blog was set up as a forum for anyone interested in the news on www.bigpinkshark.com that the sharks commonly sighted by scuba divers on Chumphon pinnacle, Koh Tao, Thailand, which are generally identified as grey reef sharks are in fact bull sharks.

Saturday, 15 September 2007

Welcome to the Big Pink Shark Bull Shark Blog

Welcome to the Big Pink Shark "Bull Sharks at Chumphon" Blog. Please feel free to post your comments on the article, questions and observations here. Robin and Richard.


Anonymous Anonymous said...

Fantastic article - I too have dived with these sharks and was told by my dive master that they were grey reef sharks. I can't believe I've really dived with bull sharks - you are right, there is a load of bull on Ko Tao! Best wishes, Sky

15 September 2007 10:24  
Anonymous Anonymous said...


17 September 2007 03:24  
Blogger Nick said...

Brilliant article guys, having seen some of the bigger sharks at Chumphon I have always wondered whether they were really big reefies or actually the bulls that were hinted at. You convinced me that I should spend my 2 week holiday back on the rock with the sharks!

17 September 2007 04:33  
Blogger scuba junction said...

I have been diving in Koh Tao since 2000 and have always said that there were bull sharks circling those waters.
We first started seeing sharks there in 2001, but in the first years they came and went with long intervals. In the beginning there were mainly grey reef sharks (the white dot on the dorsal fin is unmistakenly a charactiristic)and the occasional bull (bulkier body feature and different shape dorsla fin), but most dive professionals on Koh Tao have limited experience diving elsewhere and I also was not taken serious.
The last 2 years I noticed that shark sightings were almost always guarenteed every dive but I almost never saw grey reefs anymore.
I assume that there are still grey reefs around but have been 'pushed' away by the less shy bull, hence the constant sightings of sharks.
I went diving myself there last Friday and saw at least 8 different sharks, all bulls...

'K' Scuba Junction (diving since 1989)

17 September 2007 16:13  
Blogger Robin and Richard said...

K of Scuba Junction, what you say makes a lot of sense - the white mark at the end of the dorsal fin is a definite sign of a grey reef rather than bull shark, even if not all populations of grey reefs (eg. Australia) carry this marking.

It is not difficult to see why Bulls might certainly be intimidating for Grey reefs and push them off the reef – It would be good to get hold of some old photos of these grey reefs on Chumphon. We still haven't seen any photos of grey reefs at Chumphon so far but certianly it seems from what you say that they were ousted by the bull sharks several years ago.

Robin and Richard

22 September 2007 15:41  
Anonymous ABintheUK said...

If Geremy Cliff has confirmed it, this must be right. Slightly puzzled that other South Africans diving Chumphon regularly haven't drawn the same conclusion (Tony Lowe are you focusing too much on the camera and not on the wildife?). I look fwd to seeing them again next year, with even more respect.

20 December 2007 03:22  
Blogger gerryff said...

I know chumpon and i think that the "bull"could be Pigeye shark(carcha.amboinensis).This shark is not very well know but he looks like the bull:same color and white underside but the first back fin is 3.2 time bigger than the second(the bull it is MAXIMUM 3.2)Both make a competition for the area:when you see pigeye there are no bull and vice versa

27 December 2007 05:02  
Blogger Robin and Richard said...

Thanks for your post Gerard. The Pigeye (or Java) shark was certainly a contender, but Geremy Cliff (South African Shark expert) ruled it out due to the second dorsal being proportionately larger in the Chumphon sharks (the Java has a much smaller second dorsal fin as you correctly point out). Thanks for the interest in the article – we will be publishing another in Asian Diver (April edition) and are about to launch a shark database!

Do have a look at the facebook group “Bull Shark or Bull Shit” which has been going for a few months now with some interesting observations.

27 December 2007 13:42  
Anonymous Anonymous said...

Hi guys,
Am just back from Thailand and Myanmar. I was first very sceptical about bull-sharks on Chumphon Pinnacle, since I had seen only grey reefs before. But already last year I had some doubts about two biggies - thought that these were just big female grey reefs with faded markings. Well, this February I came to the conclusion that these are indeed bulls, although with a lighter colour than those I had seen in Myanmar.
During a surface break we had even one breeching and spinning. Never saw that before.
In any case, diving with bull-sharks is as thrilling as encountering a Great Hammer near Blue Corner, Palau some years back.


Daniel Fischer, Belgium - Facebook

16 February 2008 03:00  
Blogger 01dibble78 said...

Hi...the main noticeable difference with the bull is the general weight. They are alot fatter than the more sleek grey reef! The bull also has a shorter nose! The bull has a different shape dorsal fin (more stereotypical shark fin shape) than the reef which is, on any variety of reef shark, more vertical. The eye is also a give away.....different colour and style with a beady pupil on the bull....but only in juveniles. As the bull grows the eye becomes darker. The dorsal fins on the reef are longer and thinner as they are built for speed! However not all grey reefs have the discoloured speck on the dorsal....I dived with the sharks on chumporn for 2 years and have also dived with bulls here in australia! It is a very un noticeable difference to the unexperienced eye...but I have also distinguished grey reeks on chumporn swimming next to juvenile bulls! Its great to see !

11 April 2008 20:22  
Blogger Robin and Richard said...

Thanks for your input on this 01dibble78. We agree with you that the ID is difficult but have yet to see any photographic evidence that there are still grey reef sharks on Chumphon - if you have some photos (particularly of both species on one dive as you claim) we would love to see them as we are coming to the conclusion that the greys have moved away from Ko Tao for some reason - possibly to do with warmer waters since 2000. Bull sharks don't seem to mind the warmer water but there is certainly some evidence that grey reef sharks may need to access colder water (eg. diving deep) in order to maintain their population. Do let us know if you have any photos of greys on Chumphon.

20 April 2008 14:37  
Anonymous Anonymous said...

Hi Richard and Robin!

Congratulations to your very interesting site concerning the Bull sharks on Chumpon pinnacle.

As a marine biologist I was really shocked that I did not realized that it where bull sharks what I was filming at Chumpon in 2007.

Thank you very much for your very professional investigations!

here are my videos of the sharks in facebook:




04 May 2008 07:20  
Blogger DaShark said...

Hi Robin and Richard
greetings from Fiji.
Very interesting, tho allow me some comments.
We've been diving with both bulls and greys for 10 years (see fiji-sharks.com) and quite frankly, I've never quite seen the coloration of your "bulls". We really do get them in all sizes but none have that conspicuous black edge to the caudal fin. Mind you, it may well be a local coloration, or the coloration of some really tiny individuals: but it might be worth your while to inspect the possibility that they are amboinensis. Alas, for that you'd have to get a specimen, preferably from some local fish market - comparing relative fin sizes just won't quite do.
But you may have well found the only "reliable" spot where one can encounter that species, so maybe it would be worth your while?
Other than that, I beg to differ on the cleaning station video: black trailing edge of caudal, longer snout, higher first dorsal are all indicators for grey reefs, not bulls!
Best Regards and congratulations on your exciting find!

07 June 2008 09:20  
Blogger Robin and Richard said...

Thanks for your comments Mike - interesting to hear from other parts of the world and to compare characteristics and features of these sharks. I am sure there will be local colour variations in bull sharks, just as with the grey reef, for instance, in some parts of the world they have distinctive white trailing edges to their first dorsal fin. Indeed this might be the reason that this particular population has been mis-identified as grey reef sharks for so long. I note that in the americas, juvenille bull sharks also have black edges to their caudal fins.
I would love to believe that these are Java (or Pigeye) sharks, but the shark experts are quite confident about the fin sizes and to my knowledge amboinensis is also not identified by a black edge to its caudal fin, but there are not so many comparable photos available. I agree that some local research would be a good idea.
Regarding the cleaning station video, we stand by our ID, but we included this video precisely to demonstrate the ease with which the confusion between species is made. The shape of the first dorsal fin is quite different from the upright 'isoceles triangle' shape of a grey reef. We are confident they are bulls. Thanks for your interest and input and hoping to see you in Fiji very soon!

08 June 2008 07:08  
Anonymous Lars Bindholt said...

Bulls in Thai waters is not very well known. In the Andaman Sea I noticed the same confusion around Hin Daeng: There are grey reefs around. I saw only leopard sharks, Blacktips and.... bull sharks although on one occation actually two grey reefsharks. The case of the black band on the tail may confuse most divers. Have a look at http://hjem.get2net.dk/thaihaj-LB/ Look under Bull shark.
Lars Bindholt

19 June 2008 05:14  
Anonymous trevor said...

hi guys
ive on koh tao for 4 years working as videographer im know statin my own shop and just baught 2 ribs
really interested in researching these sharks
i have houndreds of dives at chumpon and know these sharks and this dive site very well
any thing i could do to help monitor these sharks sounds like a good idea as we have a serios problem with long line fishing at chumpon pinnicle
anything you need at all let me know at trev_emerson@yahoo.ie

05 July 2008 21:11  
Anonymous Matt said...

Pigeye vs bull has to be a lot harder to call than grey reef vs bull - the d1/d2 ratios aren't *that* different - the upper dentition in amboinensis is supposedly serrated and broader then leucas.

Now theres a challenge...

Fantastic fish to dive with either way!

19 July 2008 06:09  
Anonymous Anonymous said...

Thanks Lars, Trevor and Matt. Would be good to get some photos of these sharks' teeth for definite ID, but difficult to set up a tagging/ capture and release program remotely (we are no longer in Thailand). Failing that, if anyone sees or hears of one of these sharks being taken by fishermen, perhaps you could get a close-up photo of the teeth - but at the same time, I hope this is not possible (as I do not wish to encourage fishermen to have an excuse to fish them!).

03 August 2008 20:22  
Anonymous Anonymous said...

I was convinced since 2000 that the sharks around Chumpon are not greys. Photos I have send at that time to shark experts indicated that there was a high evidence that these sharks might be pig-eye-sharks.
If you have a look on the published photos of sharks of Chumpon at least some of the sharks shown have a fin ratio of >3.2. To confirm the species it would be necessary to have a more detailed investigation

04 August 2008 09:17  
Blogger Robin and Richard said...

Thanks for the comment anonymous, but did you mean to say a ratio of >3.2 (a bigger ratio means a smaller second dorsal fin) Do you mean that the second dorsal fin is smaller than 1/3 the height of the first dorsal (pigeye) or bigger (bull)?

24 August 2008 18:10  

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