The African penguin joins the list of species said to be threatened by climate change - and overfishing.

Researchers from the UK and South Africa say penguin numbers in the Benguela upwelling ecosystem have halved in just 30 years.

The sardines and anchovies they feed on have moved eastwards, due to changes in water temperature and salinity.

Scientists tagged juvenile penguins and found them traveling fruitlessly to their old hunting ground, caught in a so-called ecological trap.

11 PHOTOS African penguins See Gallery African penguins TO GO WITH AFP STORY BY JUSTINE GERARDY == African penguins are pictured on March 16, 2011 in Simon's Town near Cape Town, South Africa. Africa's only nesting penguin was reclassified as endangered last year due to it being nearly wiped out, likely as a result of competition for food from commercial fisheries and shifting fish stocks. One of the world's 18 penguin species, Birdlife International has warned that the African penguin is edging closer to extinction. AFP PHOTO / STEPHANE DE SAKUTIN (Photo credit should read STEPHANE DE SAKUTIN/AFP/Getty Images) Young African Penguins head out to sea, after being released at Stony Point, Betty's Bay, about 130Km from Cape Town on January 18, 2010, in Cape Town, South Africa. A group of 63 penguins are released back into the sea after being rehabilitated at the South African Foundation for the Conservation of Coastal Birds, in Milnerton. These birds were part of a bigger group of 300 chicks that were abandoned by their parents. Scientists are unsure of what causes the adults to leave the chicks, but suspect changes in fish stocks, predation by a growing seal population, even climate change, can contribute to this phenomenon. AFP PHOTO/RODGER BOSCH (Photo credit should read RODGER BOSCH/AFP/Getty Images) A worker at the South African Foundation for the Conservation of Coastal Birds (SANCCOB), in Milnerton, loads a young African penguin, into a box, on January 18, 2010, in Cape Town, South Africa, before being released back into the sea. A group of 63 rehabilitated penguins were released at Betty's Bay, about 130Km from Cape Town. These birds were part of a group of almost 300 chicks that were abandoned by their parents. Scientists are unsure of what causes the adults to leave the chicks, but suspect changes in fish stocks, predation by a growing seal population, even climate change, can contribute to this phenomenon. The pink painted spots will allow researchers to identify and monitor the progess of these birds for a few months. AFP PHOTO/RODGER BOSCH (Photo credit should read RODGER BOSCH/AFP/Getty Images) Young African penguins are fed at the South African Foundation for the Conservation of Coastal Birds, in Milnerton on January 18, 2010, in Cape Town, South Africa, before being released back into the sea. These birds were part of a group of almost 300 chicks that were abandoned by their parents. Scientists are unsure of what causes the adults to leave the chicks, but suspect changes in fish stocks, predation by a growing seal population, even climate change, can contribute to this phenomenon. AFP PHOTO/RODGER BOSCH (Photo credit should read RODGER BOSCH/AFP/Getty Images) Young African Penguins are fed at the South African Foundation for the Conservation of Coastal Birds (SANCCOB), in Milnerton on January 18, 2010, in Cape Town, South Africa, before being released back into the sea. These birds were part of a group of almost 300 chicks that were abandoned by their parents, and rehabilitated at SANCCOB. Scientists are unsure of what causes the adults to leave the chicks, but suspect changes in fish stocks, predation by a growing seal population, even climate change, can contribute to this phenomenon.. AFP PHOTO/RODGER BOSCH (Photo credit should read RODGER BOSCH/AFP/Getty Images) Two workers check the wing rings of young African Penguins at the South African Foundation for the Conservation of Coastal Birds, in Milnerton on January 18, 2010, in Cape Town, South Africa. A group of 63 rehabilitated penguins were released at Betty's Bay, about 130Km from Cape Town. These birds were part of a bigger group of almost 300 chicks that were abandoned by their parents. Scientists are unsure of what causes the adults to leave the chicks, but suspect changes in fish stocks, predation by a growing seal population, even climate change, can contribute to this phenomenon. AFP PHOTO/RODGER BOSCH (Photo credit should read RODGER BOSCH/AFP/Getty Images) QUALITY REPEAT --- A group of about 100 African penguins are released into the sea near Cape Town September 16, 2005 after recovering at the SANCCOB (South African Foundation for the Conservation of Coastal Birds) rehabilitation centre. About 400 of these endangered birds were treated by volunteers at the centre after being affected by an oil slick. Conservation officials suspect the oil spill may have been the result of vessels illegally flushing bilges off the South African coast. REUTERS/Mike Hutchings Rehabilitated African Penguins are released at Boulders beach breeding colony in Cape Town September 26, 2009. The release formed part of a national 'African Penguin Day' event organised by SANCCOB (Southern African Foundation for the Conservation of Coastal Birds). SANCCOB specializes in the conservation and rehabilitation of endangered birds that are either abandoned chicks, injured birds or birds that have been affected by oil spillages. Picture taken September 26, 2009. REUTERS/Mark Wessels (SOUTH AFRICA ENVIRONMENT ANIMALS) A group of about 100 African penguins are released into the sea near Cape Town September 16, 2005 after recovering at the SANCCOB (South African Foundation for the Conservation of Coastal Birds) rehabilitation centre. About 400 of these endangered birds were treated by volunteers at the centre after being affected by an oil slick. Conservation officials suspect the oil spill may have been the result of vessels illegally flushing bilges off the South African coast. Volunteers carry crates containing a group of about 100 African penguins which they released into the sea near Cape Town September 16, 2005 after the birds recovered at the SANCCOB (South African Foundation for the Conservation of Coastal Birds) rehabilitation centre. About 400 of these endangered birds were treated by volunteers at the centre after being affected by an oil slick. Conservation officials suspect the oil spill may have been the result of vessels illegally flushing bilges off the South African coast. A group of about 100 African penguins are released into the sea near Cape Town September 16, 2005 after recovering at the SANCCOB (South African Foundation for the Conservation of Coastal Birds) rehabilitation centre. About 400 of these endangered birds were treated by volunteers at the centre after being affected by an oil slick. Conservation officials suspect the oil spill may have been the result of vessels illegally flushing bilges off the South African coast. 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"We did some population modeling which suggests the Western Cape population is about 50 percent the size that it would be if this trap wasn't operating..... The African penguin is endangered. It's declined by more than 50 percent over the last three generations, so over 30 years. The Western Cape population which used to be the stronghold has declined by about 80 percent in the last 11 or 12 years," said Dr. Richard Sherley, Research Fellow at University of Exeter and Bristol Zoological Society.

Juvenile penguins make their first journey to the sea alone. Instinctive cues which used to help them find food now put them in danger.

"They travel over thousands of kilometres to get to these particular locations. They arrive and they find that the fish is no longer there because stocks have either been collapsed, as in the case of Namibia, or the fish have shifted their distribution eastwards. So they're going to the right places but when they get there they're not finding the food that they need and we think they're cueing in on particular cues that tell them that these should be good parts of the environment, but the human impacts have broken the system in a certain way," added Dr. Sherley.

Researchers have called for some fishing to be suspended and major conservation action in the Benguela.

Otherwise the endangered African penguin might die out.