Joint Basking Shark Project: Population Estimates and Real Time Tracking
This SOSF funded project aims to build a comprehensive photographic database of UK observed basking sharks, while simultaneously using satellite tracking to observe and investigate their migratory movements into international waters.
Why this is important:
At up to 10-11 meters in length and 5-7 tonnes in weight, the basking shark (Cetorhinus maximus) is the second largest fish in world. However, as a result of fishing pressure, its global existence is now seriously threatened, with the species’ total population thought to have diminished to around only 8,200 individuals.
The basking shark, the world’s second largest shark, is like the whale shark a planktivore, but confined to temperate waters. It has long been exploited in the Atlantic for its liver oil, and more recently has largely disappeared from the Pacific, as a result of the Asian demand for shark fin. More recently the work of the SOSF signature project led by Dr. Mauvis Gore has both provided additional insights into this charismatic species and collected data suggesting that in the UK, following protection, numbers may perhaps be recovering. The SOSF sponsored the 2009 Basking Shark Conference concluded that the best to monitor numbers would be to implement a photo-identification scheme that can generate population estimates through mark-recapture modelling. Consequently in April 2010 a community photo-ID project was launched involving four separate research teams – based respectively in Scotland, the Isle of Man, England and Ireland – and a joint database established at the Shark Trust in Plymouth. Currently work is underway to catalogue the sharks sighted and check for matches with those photographed in previous years. In addition teams have been collecting tissue samples from which an independent assessment of population structure and size can be derived. This application is for funding to enable both types of work to be continued into a second essential year. The Shark Trust will establish a sophisticated SOSF badged website as a portal through which research teams and other parties can both upload photographs and review the existing catalogue. In addition since it is key to maintain public support for basking shark protection it is proposed to open an SOSF-supported Shark Education Centre at Breachacha Castle on the Isle of Coll, adjacent to probably the most important basking shark aggregation site in the UK.
Aims and Objectives
The aims of the project (as described in the original application) are:
- To derive reliable estimates of population levels and trends for basking sharks in NW Europe, through boat-based surveys and photography for identification purposes, collection of tissue samples for DNA analyses.
- to promote public awareness of basking sharks as a means of securing their protection and conservation through an environment exhibition at Breachacha Castle (Isle of Coll).
Project collaborator Colin Speedie has just passed on photos that prove to be the re-sighting of an individual basking shark after the longest period we have yet on record. The Basking Shark Photo-ID project has now built up a large…
At times during our latest survey, distinguishing at a distance between Orca (killer whale) fins and basking shark fins as they broke the surface was a real issue. On occasions a pod came quite close to our survey boat, on…
This year our Basking Shark Project has focused on applying the methods we have developed for recognizing individual sharks from high quality photographs on a wider scale. We have been comparing data collected in different regions, and in different countries. …
We should have updated our basking shark blog before now, but the late summer was beset with various difficulties and delays, not least of which was the poor weather. The calm periods most productive for fieldwork were fewer in number…
A shame to be launching this record of SOSF’s basking shark project after the Basking Shark Season is over, but the entry serves to mark the start of the IT work required for the launch (or re-launch) of a key…