News & Events

08-Aug-2008
ITV Film about Manx Basking Shark Watch
07-Aug-2008
French Film Crew Here to Film Basking Sharks
31-Jul-2008
BBC here to film for "LIFE', a new 10 part series similar to the 'Blue Planet'.
30-Jul-2008
Basking sharks at site of runway extension: the need for silt traps during construction work.
29-Jul-2008
THREE basking sharks, David, Liz and Colin, tagged in one perfect basking shark day July 27th, 2008

Basking Sharks in the Isle of Man 2007

Written by Jackie Hall MSc (Coordinator for Manx Basking Shark Watch)

Graphs and maps by Dr Philippa Tomlinson (DAFF)

It has been an amazing year. We counted basking sharks, we watched them, we tagged them and we filmed them. The following report gives you maps, graphs and photographs to give you an overview of the 2007 Manx basking shark season: enjoy!

Thank you all so much for sharing your basking shark sightings with Manx Basking Shark Watch and hence with the public at large. We could not do it without you.

YOUR 2007 REPORTS

Overall results

You have sent in 685 basking shark sightings reports this year compared to 257 sighting reports in 2005 and 522 in 2006. The graph below shows this increase in reporting quite clearly.

2007 was a very good basking shark year, no doubt about that but we must not forget that the new website has made it much easier for people to report their sightings.

 If you look at the map ‘Basking Shark Sightings 2007” you can see that as usual most of the sightings are on the extreme south and the southwest of the Islands coast. Most of these sightings are for single sharks but some of them were for very large groups of sharks. For example there was one report was for 32 sharks (off The Ayres Visitor Centre), two reports were for 36 sharks (4km and 7 km NW of Peel), and a fisherman reported seeing ‘sharks as far as the eye could see’ (off Lynague). He stopped counting when he got to 45. It is important to remember that this does not mean that there were not necessarily 1000s of sharks in Manx waters in 2007 as the same shark may have been reported many times.

The first shark sighting was in March this year. If you look at the graph below called ‘Number of sightings in ‘07’ you can see that the pattern was much the same as any year, a couple of basking sharks in March and April, a few in May, more in June and numbers peaking in July.  August saw a lot more sharks than usual.  September saw only a few, with the last one seen on September 12th.

This pattern of sightings is what we would expect except the we had a big surprise when John Galpin of Manx Whale and Dolphin Watch www.mwdw.net saw a 7 foot long basking shark off Laxey Head on November 4th! It was, as they say, the exception that proves the rule.

Results Month by Month

The maps that follow show the basking shark sightings for each month as red dots.

March saw just one basking shark sighting off the coast near Douglas. Early sightings are often off this bit of coastline whereas you hardly ever see them there later in the season.

As you can see, the same pattern in April, just one sighting off the coast just south of Douglas.

May sees the real start of the Manx basking shark season. You will notice that there are quite a few sightings off the southern tip of the Island as well as the normal spread up the south and west coast.

June. The Manx basking shark season is in full swing. You will notice that there are still quite a few sightings in the south, especially around Langness.

July sees basking shark numbers at their highest. Most of the sightings are on the west coast.

By August the sightings numbers are well down. A lot of the sightings are around Peel.

By September the season is virtually over.

But as you can see, November gave us a little surprise off Laxey Head!

Basking Shark Sizes in 2007

As you can see from the graph below ‘Number of Basking Sharks in Each Size Category’ small sharks are uncommon and the most common shark size is 6-8m.

Look at the graph of ‘Sizes of Basking Sharks May to August 2007’. It shows you when you are most likely to see basking sharks of the different size categories. It is quite difficult to estimate the size of a shark but we are very fortunate that 70% of our sighting reports have size estimates for the sharks.  The mid-blue bars are for very small basking sharks, ‘new borns’ of just 1.5 to 2 m length. There are relatively few of them and they occur in June, July and August.  It is amazing that we get so many of these as it is very rare to see them. We had 29 sightings of newborns on the Isle of Man this year. I suspect that this might be more than the rest of the British sightings but the Marine Conservation Society does not have its results published for 2007 yet. As you can see looking at the mauve columns for the 2-4m long, young-of-the-year, sharks we also had a lot of them, 177, most of them in July.  Medium-sized sharks of 4-6m were seen in all months but were most common in July and August.  6-8m sharks were also seen in all months but again they were most common in July. Very big sharks of over 8m length (dark purple) were  present in every month.

Your Reports of Courtship Behaviour or ‘Social Swimming’.

In the summer months we get many reports about the interesting behaviour of basking sharks. It is thought that many of these interesting behaviours are examples of basking shark courtship behaviour. Scientists are always sceptical about labelling this as courtship and the scientific papers refer to these behaviours as “putative’ courtship behaviour. For simplicity we will omit this word for the rest of this account and just call it courtship.

 

In 2007 you have sent us reports of many basking shark courtship events such as nose – to – tail following, parallel swimming, ‘jousting’ and breaching. We are very lucky on the Isle of Man because a lot of this behaviour is seen and now that the MBSW reporting scheme has been going for 3 years many of our reporters are looking at this behaviour with an informed eye. We hope to publish this invaluable data in a scientific paper in 2008. Thank you all for contributing to this data collection. Here is a brief summary of what you found this year. There is much more detail but we will keep it simple here.

Courtship Behaviour Reports

If you look at the graph below, of basking shark courtship, you will see that basking shark courtship behaviour was most common in June and July. This is what we normally see; we were just very lucky to witness rather a lot of it in 2007.

Looking at the map below “Basking Shark Courtship behaviour 2007’ you will see that all of these behaviours have been seen along the West coast with clusters off the Calf, Fleshwick Bay and off Peel. These clusters may occur because it is relatively easy for people to observe basking sharks there. Boats take people out to watch sharks in these areas and it is possible to see these behaviours from the shore at the Sound and Fleshwick.

Formation Swimming as Courtship Behaviour.

You may be lucky enough to see basking sharks swimming very close together. By this I mean that 2 or more sharks are swimming less than half a shark body length apart for a minute or more. Sometimes they swim one behind the other in a nose – to-tail fashion. They can be so close doing this that they almost touch one another.  At other times they swim parallel to one another, usually about a quarter shark body length apart. I have observed sharks swapping from one pattern to the other and back again. Several of the ‘courtship’ reports for this year are of 3 sharks together. As a picture is worth a thousand word look at these two photographs-

Graham Hall took this photo on 07/07/07. It shows 2 sharks ‘close following’. This is thought to be a form of courtship. You can see two shark’s dorsal fins and the rear sharks tail fin. These sharks are almost touching nose -  to - tail but we count it as nose to tail even if they are up to half a shark body length apart. They need to be doing it for at least 30 seconds for us to think that it might be courtship. Sometimes they do it for hours. These sharks were alternating between this and another form of courtship called parallel swimming (see photo below).

Graham Hall took this photo on 07/07/07. This is the same group of sharks as the nose to tail behaviour. These two basking sharks are  ‘parallel swimming’. This is also thought to be a form of courtship. You can see the two sharks dorsal fins. They are normally about a quarter of a shark body length apart when they do this.

Breaching.

Basking sharks sometimes breach. This is very spectacular, you do not really expect to see something the size of a bus leap clear out of the water. It is thought that this is a behaviour associated with courtship.

There is some question about whether breaching is associated with courtship behaviour but it is normally done by sexually mature sharks of more than 6m length and it tends to be seen on days when other courtship behaviours such very close formation swimming is reported.

 The graph below shows how many breaching events were reported to MBSW in 2007. As you can see most of the breaching occurred in July so look out for this in 2008. IF any breaching behaviour is reported I suggest you keep well away as you don’t want a shark the size of a bus to land on your boat! This does seem to have happened once in a Scottish town called Carradale in the 1930s. Let’s not have it happen here.

SATELLITE TAGGING WORK

We successfully tagged 2 basking sharks with satellite tags. Dr Mauvis Gore from Marine Conservation International came over from Scotland to show us how to do it. Dr David Rowat from the Seychelles whale - tagging project is analysing the tag data as I write this. These tags were £3000 each. We are VERY grateful to Tower Insurance, Dennis Drummond and DAFF for funding 3 tags. The Gough Richie Foundation gave us £2000 towards our boat costs. We used Bob Taylors boat ‘Gemini’ for the tagging work. Very nice bacon sandwiches Bob, thank you! The tagging findings are ground – breaking. More of that later when the scientific papers have been published! Hopefully at least one paper will be published in Nature early in 2008.

This is a satellite tag. As you can see it is quite small, that is a sheet of A4 paper behind it. This wonderful instrument can measure the position of the shark, the water temperature and the depth. We programmed the tags to stay on for 100 days. We don’t get any information until they pop off and start to send us their data. Waiting can be a bit frustrating.

There are two levels of information that we can get from the tag once it pops up. When they do pop off they beam their information to the Argos satellite, which then emails the information down to us. IF we are lucky enough to retrieve the actual tag we can have much more data by removing the information chip from it. We have retrieved one of the tags so far and another has popped up and given us its information by satellite only.

FILMING

As if that wasn’t enough our Manx basking sharks became famous when they were featured in BBCs ‘COAST” series. 2007 saw 3 film companies filming our Manx basking sharks. Tigress Productions filmed the tagging for ‘The One Show’ on BBC1, also Border TV and a Belgian Film company.


Miranda Krestiovnikoff off Port St Mary during the filming of Manx basking sharks for BBC ‘COAST”

SOME GREAT SHARK PHOTOS

We have received 100s of great photos from you this year. These include some great video footage. You will find some of these video clips on the website. I will put more on in 2008. It’s a question of getting around to it and the video format being compatible with the websites requirements. Paul Steer, our software expert, has done a fantastic job of putting these on for us. You will also find some truly excellent basking shark photographs attached to the individual sighting reports, including some very small sharks and some courtship events.

I apologize for the dearth of still photos in the photo section. They WILL be put on eventually. We have had some technical problems but these will be sorted for 2008 and the very best of the 2007 photos will be put on then as well.

In the meantime I leave you with a great example of the 2007 photos. This great photo anchors the basking shark so firmly in the Manx landscape.


Ian Judd: Basking shark and rainbow in Peel Bay 2007

Acknowledgements and MANY thanks

The sighting reports

As I said at the beginning of this report, we could not have done all this without every one of you being kind enough to share your sightings, photos and video with Manx Basking Shark Watch.

The website

The new website has been a complete success. We are planning to improve it still further with automatic mapping and graphing for 2008. Paul Steer www.deltait.co.uk, our software expert, has done the most fantastic work for us. Thank you so very much. The website costs have been funded by DAFF. We could not have afforded it without this funding. We hope to get more funding from DAFF for the new phase of the website.

The Tagging

The tagging work would not have been possible without Dr Mauvis Gore, David Rowat, Bob Taylor, Dr Fiona Gell and my long suffering husband Graham Hall.  Most importantly we could not have done any of it without our financial sponsors.

Tower Insurance, DAFF and Dennis Drummond of Canada each paid for one £3000 tag. Their generosity is about to reap GREAT results. Well done and thank you for your generosity. DAFF paid for Dr Gore to come across for the tagging. The Gough Richie Foundation sponsored us generously for the boat hire. David Stacey of Tower Insurance and Dennis Drummond have both offered to sponsor another tag next year.

 Dr Gore actually put the tags on and she is analysing the data as it comes back. We could not have done it without her expertise. We certainly couldn’t have done it without Graham Halls improved ‘pole tagger’. David Rowat has been responsible for downloading and interpreting the data from the Argos satellite. How he has fitted it in with his own work on whale shark tagging in the Seychelles is not quite clear!

We used Bob Taylors boat “Gemini’ for the filming and tagging work. Bob Taylor and his crew, John Paynton and Dave Ogden handled Gemini with expertise and precision. This allowed us to get close enough to these huge beasts without harming the sharks or risking our lives and limbs by being in a small boat. The hospitality, especially the cake and bacon sandwiches, was much appreciated. Bob let us hire Gemini for half his normal commercial rate so, effectively, he was sponsoring us as well as letting us hire his boat.

Data Analysis.

So now we come to one of the most important acknowledgements of all. If you look at the recent sightings page for 2007 you will see a long list of sightings. Each sighting is interesting, the photographs and stories bring each sighting to life BUT it is almost impossible to get an overall impression of the patterns of sightings. It is hard to see WHERE most of the shark sightings are and when basking sharks are seen at different locations around the Island. You cannot really pick out WHEN the best times are to look for sharks. The different SIZES of sharks are not obvious either. To do this the data needs to be analysed and interpreted. For this we need PICTURES, maps and graphs. All the maps and graphs you see in this report have been made possible by the huge amount of work done by Dr Philippa Tomlinson of DAFF. With 686 individual sightings reports and no mapping program I would have been completely unable to process all the 2007 sightings without her extensive help. Many, many thanks!

More to Come!

I have lots more to add to this 2007 report but it will have to wait until the New Year.

Jackie Hall


Manx Basking Shark Watch 2007