After watching this video of a pregnant female whale shark caught recently in Pakistan, it will come as no surprise that whale sharks are in fact getting smaller.
Over a ten year period the average size recorded by observers has shrunk from 7m to 5m.
Whale sharks are caught for food and their fins in some Asian countries and Australian researchers suspect this is causing the decline.
The data comes from companies which run expeditions to watch whale sharks in Ningaloo Marine Park off the north-west coast of Australia.
Whale sharks do not reach sexual maturity until they're 6 or 7m long, so the signs are not encouraging.
More research on whale shark biology and worldwide protection is needed if the world's largest fish is to be saved from extinction.
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