January 9, 2010 Featured Article Read More →

Basking Shark hotspot

A NEW report has identified two areas on the west coast of Scotland – Gunna Sound between the islands of Coll and Tiree and the sea around the islands of Canna and Hyskeir – as ‘hotspots’ for basking sharks, the second largest fish in the world.

The report, published by Scottish Natural Heritage (SNH), identified the hotspots from the consistently high numbers of basking sharks seen at the surface, often in large groups. On one occasion in July 2006, 83 sharks were recorded round Canna, with the highest daily tally round Coll in August 2005, with 94 sightings. Frequent displays of courtship-like behaviour, including breaching – where the shark leaps clear of the water – suggests that both areas are important for sharks looking for a mate.

The report interprets data collected along the west coast of Scotland between 2002 and 2006 by The Wildlife Trusts’ Basking Shark Project. Set up because so little was known about basking sharks, the project has carried out surveys along the western seaboard of the UK over the last nine years.

Suzanne Henderson, marine advisory officer for SNH said: “It is very exciting to find out that the west coast of Scotland is one of the best places to spot these majestic animals. The figures show how important these sites are nationally, and possibly globally.”

Colin Speedie, the shark expert who carried out the research for SNH said: “Basking sharks are fascinating but we’ve still got much to learn about them. They are huge – the length of a double decker bus – but they feed entirely on plankton, tiny animals that drift through the water. These minute creatures pass through their enormous gaping mouth and are filtered out by their comb-like gills. In one hour an adult shark filters enough water to fill a 50m Olympic sized swimming pool.

Basking sharks can grow up to 11m in length and 7 tonnes in weight. They are also long lived, with some surviving as long as 50 years. Because they are slow moving, slow to mature and long lived, they are very vulnerable to human disturbance and impacts. For generations they were hunted for the high oil content of their large livers. More recently they were hunted in European waters for their colossal fins which reportedly sell in East Asian markets for an average price of US $50,000.

SNH is producing a leaflet and poster for leisure and commercial boat users. These will be sent out to boat clubs and training centres in the spring.

The report will also help consider what action could be taken to look after basking sharks in the waters of the west of Scotland in the future, if climate change, offshore developments, fisheries or marine tourism became an issue.

More details at on the BBC and Glasgow Herald web sites.

Posted in: Shark Bites
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