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Analyzing the Distribution of Basking Sharks |
Although basking sharks (Cetorhinus maximus) feed exclusively on plankton, they can grow to more than ten meters in length and over five tons in weight.
In the spring, the friendly giants migrate in pursuit of blooming plankton, heading to the waters around England and Scotland. Basking sharks are highly endangered and are thus strongly protected in these waters and worldwide.
© Colin Speedie / Shark Foundation
Illustration: Basking sharks (Cetorhinus maximus) frequently wander through the ocean with their jaws wide open in order to filter plankton from the water.
The project investigates the influence of fishing nets, injuries caused by ships (these giants frequently swim on the water surface and are thus prone to such injuries) and other behavioral and reproductive disturbances of basking sharks. This research will form the basis for establishing recommendations to protect basking sharks in British waters.
Most project work is performed by volunteers, preferably local people in order to foster awareness of local shark protection.
This research is being carried out in the following areas:
- Cornwall
- Devon
- Whales
- Irish Sea
- Firth of Clyde
- Hebrides
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Photographic Identification of Basking sharks
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Studying the behavior of individual basking sharks over several years means that some individuals must be clearly identifiable. Sharks can thus either be tagged, or a photo database can be set up in which exterior characteristics are clearly displayed. The project team decided on the photo database since it would cause a minimum disturbance to the sharks.
© Colin Speedie / Shark Foundation
Illustration: Clear identification characteristics on the dorsal fin of basking sharks.
Construction of the photo database is in progress. In 2004 the Shark Foundation provided the project team with a Canon digital camera with 11 megapixel resolution valued at CHF 14,000. Photographing takes place during the plankton blooming season from May to October. In 2004 data was collected between Devon and Cornwall, Whales, Northwest England, Northern Ireland and Western Scotland.
Colin Speedie uses the "Forever Changes" research ship, an 11.7 meter sailing vessel. Using a sailboat instead of a motorboat considerably minimizes any disturbances to the sharks.
© Colin Speedie / Shark Foundation
Illustration: The 11.7 m Earthwatch research ship "Forever Changes" at anchor
This is a joint project with Earthwatch Europe.
Since 2002 the Foundation assumes the maintenance costs for the research ship. Additionally, in 2003 the Foundation bought a laptop computer for the data-analysis on board, in 2004 an 11 megapixel Canon digital camera. This camera's high resolution greatly improves the photographic identification of the basking sharks, even at large distances.
Investments to date: CHF 25,500.
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