Written by Lucy Hunt MSc.
Objectives for 2011 were to build on the work from previous years deploying more tags and taking more samples for further analysis, as well as in water observations when possible and raising further awareness of the basking shark in Kerry.
The Kerry basking shark team is a small group of marine scientists and marine enthusiasts consisting of Dr Simon Berrow, Lucy Hunt MSc. and Nick Massett as well as students from Galway Mayo Institute of Technology and volunteers working at the Shannon Dolphin and Wildlife Center, we are also aided by the general public who report sightings and are interested in the study and conservation of Irish marine life. Fieldwork for the 2011 season was funded by Save our Seas foundation (photo-Id database) and The Shannon Wildlife Foundation (boat hire & fieldwork) all other work is voluntary.
Most of the research took place during the early summer months (April-May) when the basking sharks were present in large numbers due to an abundance of their food source- plankton during spring and summer plankton blooms in Irish waters.
In April 2011 the Kerry basking shark team took advantage of the good weather when a plankton bloom was evident attracting many basking sharks to the Blasket islands, Dingle Peninsula; when 52 sharks were tagged with green numbered tags over the course of two days (20th & 29thof April) and 22 shark slime samples were taken. One shark was also tagged off Power Head, Co. Cork with a red numbered tag on the 28th of April and a slime sample taken. Twenty-four zooplankton samples were taken at four different locations around the Blasket islands in the presence and absence of sharks for further analysis. There were two shark re-sightings of green tagged sharks from Kerry reported for the 2011 season.
Awareness of the basking shark around Kerry was raised through various national and international media such as newspaper articles, Facebook, Shark Trust blogs, radio, the Irish Basking Shark Project webpage and marine awareness workshops held at Kerry’s Blue flag beaches. The media coverage and workshops on the basking sharks in Kerry reached thousands of people and received very good feedback and support.
IWDG SIGHTING REPORTS FOR KERRY
There were 26 basking shark sightings reported of approximately 188 individual sharks in the Kerry region in the 2011 season on the Irish whale and Dolphin Group sightings database. The first report of a shark sighting in the 2011 season in Kerry was on the 22nd of March at Slea Head, on the Dingle Peninsula. The last reported sighting was on 12/07/2011 at Cahersiveen, Co. Kerry.
Graph 1. Shows the number of sharks and number of sightings reported to the Irish whale and Dolphin group website during the 2011 season.
The majority of sightings were reported from the Dingle Peninsula area (69%) and the rest of the reports from the Iveragh Peninsula (31%). Most of the sightings reported were from April (73%-19reports, 161sharks), May (23%-6reports, 26sharks), March (2%-1report of 1 shark), July (2%-1 report-1 shark). There were large schools of sharks (>15 sharks) reported in 15% of sighting reports all from the Dingle Peninsula area with one very large school of 60 sharks reported from the 29th of April. The two largest schools were reported on the days the Kerry basking shark team carried out fieldwork on the 20th (25 sharks) and 29th (60 sharks) of April. From previous observations in the field it is thought that for every shark seen at the surface there is probably at least three to six more sharks underwater therefore sighting reports of individual sharks are generally approximate.
TAGGING & RE-SIGHTINGS
Fifty-two basking sharks were tagged with green numbered tags over the course of two days (20th & 29th of April). Green tags G202-G256 were deployed on basking sharks off the Dingle Peninsula, excluding tags G203 which was bent and unable to be used and G248 which was lost whilst trying to deploy (see Appendix I. Table ii.). One shark was tagged in Cork waters with red tag number R315 on the 28th of April.
The total number of basking sharks tagged in Kerry from the start of the project in 2008 to date is 102 sharks. In 2011 the most sharks were tagged compared to other years actually doubling the number of sharks tagged in Kerry altogether.
TABLE!!! TABLE 1: Total number of basking shark tags deployed during 2011 and in previous years in Kerry.
There were two shark re-sightings of tagged sharks from Kerry reported for the 2011 season.
Shark tag number G217 was re-sighted on the 23rd of April approximately 14km away from the tagging site at the Blasket Islands, three days after tagging on the 20th of April.
Shark tag number G209 which was tagged on the 20th of April 2011 was re-sighted in Scottish waters on the 29th of June by divers on an eco-tourism boat at the Cairns of Coll, a number of other sharks were also noted but no other tagged sharks reported. This was the first international re-sighting of a basking shark for the 2011 season.
GENETIC / SLIME SAMPLES
Twenty-two shark slime samples were taken from 17 tagged sharks and five untagged sharks epidermis on the 20th and 29th of April around the Blasket islands at the Dingle peninsula and one slime sample from the shark tagged (R315) in Cork waters on the 28th of April (see Appendix I. Table ii).
Shark slime samples were sent to Les Noble of Aberdeen University for DNA extraction and genetic studies which have already contributed to a Masters project and will be part of Lilian Liebers PhD thesis. Samples were also taken for stable isotope analysis by Conor Ryan at the Galway-Mayo Institute of Technology (GMIT) as part of a PhD study.
Twenty–two zooplankton samples were taken around the Dingle peninsula on the 20th and 29thof April 2011. Seven triplicate zooplankton (21) samples were taken at four different sample stations using a net of mesh size 250um. Zooplankton samples were also taken at an extra site where plankton was gathered en masse near a small cove on Blasket Mor where two basking sharks were circling and feeding. Zooplankton was preserved in 40% formaldehyde for further species and biomass analysis for predator-prey studies.
Over 100 photos were taken of the basking sharks fins for fin photo ID on the 20th and 29th of April, these were catalogued by a Shannon Dolphin and Wildlife Centre volunteer and will contribute to the European Shark Trust basking shark photo ID catalogue.
One shark was re-sighted from fin photo id during the 2011 season. This was a shark first near the Blaskets and tagged (G209) on the 20th of April 2011 and then re-sighted in Scottish waters on the 29th of June by an eco-tourism boat at the Cairns of Coll. It was the first fin photo id match for the Irish basking shark project and for all basking shark research groups involved in the Shark Trust photo-id programme for the 2011 season!
Four sharks were observed breaching the surface of the water on the 29th of April at separate times. One of these sharks appeared to breach twice in succession but it is hard to know if it was the same shark or another individual due to the distance from the research boat to the sharks. Sharks were observed nose-to-tail swimming, parallel swimming and feeding on both the 20thand 29th of April. These behaviours are often associated with putative courtship.
White markings like scratch marks from rubbing were observed on the sides, undersides and pectoral fins of the basking sharks bodies. Also most of the sharks observed in the water had many lampreys attached to the genital region of their body.
This may be because the skin is damaged in this area after rubbing from copulation and easier for the lampreys to penetrate and attach. Most sharks had 6-8 lampreys attached making it very difficult to observe gender.
One basking shark was also observed excreting in water; a reddish brown substance forming a plume in the water before the shark shook its tail abruptly like shivering and swam deeper.
Three sharks were observed swimming in a continuous circle above each other whilst feeding on plankton before diving deeper.
OTHER SIGHTINGS DURING FIELD TRIPS
Two minke whales were spotted on the 20th of April and one minke whale seen on the 29th of April. There was alot of bird activity (e.g. feeding) in the areas where sharks were also observed on both days around the Peninsula.
PUBLICITY AND AWARENESS
The news of basking sharks in Kerry and the work the Irish basking shark project is carrying out reached tens of thousands of people through a number of different media. Newspaper articles were published in the Kerryman, The Kingdom, Kerryseye and The Independent about the basking sharks in Kerry. A radio interview was held with Nick Massett, from Dingle (skipper of the research rib) on the basking sharks and research carried out in Kerry. The Irish basking shark Facebook page initiated by Lucy Hunt in 2010 has grown from 207 fans to over 800 fans at the end of 2011. Twelve marine awareness workshops sponsored by Kerry County Council were held by Lucy Hunt at Blue Flag beaches in which the basking sharks in Kerry and the research carried out was presented and discussed.
Three blogs were submitted to the Shark Trust basking shark blog:
on 23/6/2011, 29/07/2011 and the 24/08/2011.
Three articles were submitted to the Irish Basking shark Project webpage during 2011 season:
1. Basking sharks aplenty in the Kingdom: 24/04/2011
2. Baskers in the Kingdom: 11/05/2011
3. Leviathans on the move: 05/07/2011
The publicity of the basking shark in Kerry and the work carried out by the Irish Basking shark Project reached tens of thousands of people in Ireland and internationally in 2011 raising the profile of basking sharks in Kerry and the potential for the area to be known as a marine mega fauna hotspot.
Recommendation’s for further research:
Continue predator-prey analysis – first plankton study in waters around the Blaskets to assess prey types that are in the area for sharks and other plankton feeders and how plankton presence changes with certain factors in the area.
The visual tagging study needs to be continued for a further 1-2 years before a critical examination of its usefulness can be carried out. We still have over 50 tags to use.
Monitor stochastic and environmental factors affecting basking shark presence in Kerry enabling a method for eco-toursim boats/tours to predict when sharks will be present in the area.
Assess lamprey species attached to basking sharks in order to know where these species are from and have a better understanding where the sharks may have come from due to their parasites.
Below is a list of possible funding sources that could be approached to further the research on basking sharks in Kerry.
Approach politicians in the area for sponsorship and funding for the Kerry basking shark project to help promote sustainable development and eco-tourism and employment for rural Ireland.
South West Kerry Partnership (SWKP):
Monitoring of basking shark presence and create plan for eco-tourism to the area and raise awareness of marine biodiversity in Kerry. Raise awareness with boat tours and marine enthusiasts’ best practice whilst at sea with basking sharks.
SWKP/An Taisce/Save Our Seas:
Develop a marine biodiversity awareness program for local schools in April and May 2013 before the beginning of the 2013 season.
Save Our Seas:
Continue to catalogue photo-id pictures and share with other research groups through Shark Trust programme.
GMIT/other university body:
Further analyse predator prey relationship between basking sharks and plankton in Kerry and the spatial and temporal presence of sharks in the region for a PhD or MSc research project.
Inland waterways/Waterways Ireland/University body:
Assess lamprey species on basking sharks and relationship to inland lamprey species found in Irish waterways (could also contribute to a PhD or MSc thesis).
2011 was a successful year for the Kerry basking shark team as research methods were improved and tagging and slime sample numbers increased by double. It was also the first year the team had in situ observations of the sharks underwater. Although the team only had two field trips and research days at sea a lot was undertaken on those days and proves that with further funding and focus on research and awareness of the basking sharks in Kerry much more can be achieved; further enhancing the conservation status of the second largest shark in the world and promoting sustainable eco-tourism for this rural area in the future.
Appendix I. Table i.Tags deployed on basking sharks in 2011
Table ii.Shark slime samples taken during the 2011 season