By Alex Kirby BBC News Online environment correspondent

The Prince of Wales is supporting attempts to save endangered birds from death in the south Atlantic.

The prince, heir to the British throne, has agreed to endorse BirdLife International's Save The Albatross campaign. The birds die in their thousands when they become trapped by fishing lines.

Until the trade in 'pirate'-caught fish is declared illegal and stamped out, species such as the black-browed albatross will continue to die

Dr Michael Rands BirdLife International

BirdLife says the number of albatrosses dying is on the increase, with some species facing extinction. Its director, Dr Michael Rands, welcomed the prince's backing, describing it as "crucial to help rally further global action to eliminate the mass slaughter of seabirds on longlines and fend off their extinction".

BirdLife says longline fishing for Patagonian toothfish, tuna and other commercially valuable species is the single greatest global threat to seabirds, killing more than 300,000 annually.

Day feeders

The fishing lines can be up to 130 kilometres (80 miles) long. Seabirds scavenge behind the boats, are caught as they try to take the bait from the hooks, and drown when they are dragged underwater.

The black-browed albatross: Badly hit (Tony Palliser)

Remedies include using bird-scaring lines with flapping plastic streamers as a deterrent to scavenging, and tubes which set the lines beneath the surface where the birds cannot reach them.

The lines can also be weighted to make them sink faster, or set at night when the large albatrosses seldom feed.

Dr Rands said there was a particular problem with flag of convenience vessels engaged in illegal fishing in the southern ocean.

Falling pairs

"Until the trade in 'pirate'-caught fish is declared illegal and stamped out, species such as the black-browed albatross will continue to die - at a rate of tens of thousands a year - until they become extinct", he said.

"Those who benefit commercially from the sale or purchase of pirated fish must be brought to book and punished."

BirdLife, a global alliance of national conservation groups working in more than 100 countries, says 17 of the 21 albatross species are globally threatened, with three more listed as near-threatened.

It says the black-browed albatross population in the Falkland Islands, the birds' global stronghold, has lost 86,000 breeding pairs over the last five years, almost certainly because of longlining.

A white-chinned petrel, also at risk (Phil Hansbro/BirdLife)