11:57am UK, Tuesday November 18, 2003

More than 12,000 animal and plant species are nearing extinction, new figures reveal.

The World Conservation Union has released a list of 12,259 species that are now either critically endangered, endangered or vulnerable.

The endangered Mekong catfish

The number is up from 11,167 last year but the organisation said new species and shifting categories made it difficult to compare the figures.

According to the 2003 Red List of Threatened Species, three species considered vulnerable last year are now extinct or 'extinct in the wild' - the Seychelles fresh water terrapin and two Hawaiian plants - the flowering Clermonteia peleane and the palm-like Cynea superba.

But 11 species previously considered extinct were rediscovered this year, including the Fabulous Green Sphinx Moth found in Hawaii.

The Red List is produced by some seven thousand experts worldwide, monitoring almost every country in the world.

Southeast Asia's Mekong giant catfish joined the critically endangered list this year. The fish is one of the largest freshwater fish in the world and can grow up to 10ft long and weigh 300kg (660 pounds). Its numbers have declined by 80% over 13 years as overfishing, habitat loss and dam construction affected breeding.

South Africa's riverine rabbit and many species of Galapagos Island snails are also on the critically endangered list, while all of the planet's 21 species of albatross are under threat.

Scientists believe 762 species have disappeared over the last 500 years. A further 58 are found only in artificial surroundings such as zoos.

The main reason for the decline is human interference as expanding cities, deforestation, agriculture and fishing continue to impact on biodiversity.