o The Frog Blog: The Basking Shark

Saturday, 9 May 2009

The Basking Shark


The Basking Shark (Cetorhinus maximus) is the second largest fish in the sea after the Whale Shark and is a seasonal visitor to the Irish coastline. Feeding only on plankton, Basking Sharks can grow up to 10 metres in length and weigh up to seven tonnes! That’s the same weight and 1.5 m longer than a double decker bus! There is limited information on the reproductive strategy of Basking Sharks. No one has ever examined a newborn basking shark or has seen a pregnant female. No one even knows where the animals give birth. However, they are believed to be ovoviviparous (eggs are laid in the womb that hatch internally, the shark then gives birth to live young) with the pups demonstrating oophagy (they eat each other in the womb).

Basking Sharks feed on zooplankton and are thought to be capable of filtering over 1800 tonnes of water per hour. Basking Sharks are found all over the world but generally in cold to warm temperate waters. They are often seen singly or in groups of up to 100 feeding at the surface. In the past, Basking Sharks have been heavily fished for their liver oil, meat, fins and cartilage but are now protected under law.

A new study has unearthed some fascinating insights into the behaviour of the Basking Shark. Scientists knew very little of their migratory habits until a group of scientists attached tracking devices. The results were very interesting, with one group of five sharks travelling over 2400km! Click here to visit the Discovery Channel Website and find out about this new study.

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