Over fishing leave tuna species at risk of extinction

Some species of tunas are at serious risk of extinction according to new research by the International Union for Conservation of Nature.

High on the 'Red List' of threatened species is the southern bluefin tuna.

It's one of five of the eight species of tuna threatened with survival or in the near threatened catergories.

The IUCN is calling on governments to take urgent action to protest the high value species.

Presenter:Geraldine Coutts
Speaker:Beth Polidoro, International Union for Conservation of Nature

POLIDORO: It's been an incredible amount of work. We spent the past four years working with scientists around the world to standardise and collect aggregate data on all species of tuna scombrids (tunas, bonitos, mackerels and Spanish mackerels) and billfishes (swordfish and marlins) and so we've actually accessed all the young species of tunas, permitos, mackerels, spanish mackerels and bell fishes, which is 61 species in total and actually surprisingly, the results are not as grim as we originally thought. Only eleven of those 61 species are in what we called threatened categories, meaning critically endangered, endangered or vulnerable, the highest categories of threat and or near threatened. So the by note is that the tunas that happen to be the longest lived and most valuable are those that happen to have the highest levels of threat and those would be the ones that you referred to five of the eight species of the large bodied tunas, these include the Southern Blue Fin which we know is spawns near Australia, the Atlantic Blue Fin, the Big Eye Tuna, all within the threatened categories and they only have the Yellow Fin and the Albecore tuna in the near threatened category, so that's probably the most alarming part of this theory is that the large bodied, more expensive tunas are the ones that are the highest threat.

COUTTS: And did it give you an indication that the overfishing, the exercise that you did, did it tell you how much this is due to overfishing?

POLIDORO: Yes, all of it is due to extensive fishing pressure.

ARKive blog - In the News: Pig-nosed turtle populations in decline

A unique reptile, the pig-nosed turtle has become an international conservation icon due to its unusual evolutionary history, morphology, ecology and behaviour.

The sole survivor of a once widespread family of turtles called the Carettochelyidae, the pig-nosed turtle has a restricted global distribution, being only found in north Australia and New Guinea Island.

However, despite its uniqueness, this species is highly prized as food, and the demand for its eggs and meat in Papua New Guinea has led to the species being dramatically over-harvested by indigenous people. Both turtle and eggs are collected for trade or consumption by local villagers.

To find out what impact such harvesting may be having on the turtle, Professor Carla Eisemberg of the University of Canberra, Australia, surveyed the numbers of eggs and adult turtles nesting in the Kikori region of Papua New Guinea. The number of turtles and eggs passing through local markets were also studied, as well as the consumption of turtles in villages along rivers and the coast.

The data was compared with a similar study of the pig-nosed turtle that was carried out between 1980 and 1982 by Mark Rose, a scientist at Fauna and Flora International in Cambridge, UK.

The similarities of the two studies meant that Professor Eisemberg and her team were able to directly compare how the turtle has fared over the past 30 years, with the results showing more than a 50% decline in pig-nosed turtle populations in the study region since the 1980’s.

The researchers found that villagers harvested more than 95% of nests that were monitored during the study. They also discovered that female turtles have become smaller on average as bigger individuals have been removed from the wild population, while the overall life expectancy of the species has also fallen.

The team fear that the 50% population decline observed in the study area since the 1980s is likely to be widespread throughout Papua New Guinea, as the species is under similar pressures elsewhere in the country.

According to the scientists, conservation plans to save the turtle are urgently needed, and, even if implemented, it will take decades for the pig-nosed turtle to recover. However, the indigenous communities living alongside pig-nosed turtles often rely on protein from the reptile to survive, meaning that planning for its conservation is a delicate balancing act.

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