Half of all tuna species at risk of extinction

More than half of tuna species at risk of extinction, say conservationists as an IUCN study shows three species are threatened with extinction, while two more will be under threat without action to help them. Five out of the eight tuna species are at risk of extinction, conservationists warned today, as they called for urgent action to tackle over-fishing.

The latest assessment for the International Union for Conservation of Nature (IUCN) showed that three species are threatened with global extinction, while two more will be under threat without action to help them.

A study, published in the journal Science, which looks at all "scombrid" fish, which include tuna and mackerel, and billfishes, which include swordfish and marlins, found that seven of the 61 known species were under threat.

The study said some of the species were heavily over-fished, with little interest in conserving them because of the high commercial value of the catch.

Pig-nosed turtle species decline by 50%

Numbers of pig-nosed turtles have declined steeply over the past 30 years, researchers have discovered.The unique reptile has become an international conservation icon, due to it having no close relatives and being considered the turtle most adapted to life underwater in freshwater ponds and rivers.

Yet demand for its eggs and meat in Papua New Guinea, one of the turtle's main homes, has led to the species being dramatically over-harvested by indigenous people.

Details of the decline are published in the journal Biological Conservation, which shows that the species have declined by 50% since 1981.