They battled with snow drifts and waded through knee-deep slush to get to their competition ground on a frozen lake in Bulgaria's southern Rhodope mountains.

The world's ice angling pros converged this weekend on the Shiroka Polyana lake, 1,500 metres above sea level, to face off at the 16th annual Ice Fishing World Championship.

Fifteen countries are represented this year - reigning champions Ukraine, along with challengers Belarus, Bulgaria, the Czech Republic, Estonia, Finland, Latvia, Lithuania, Mongolia, Norway, Poland, Romania, Russia, Sweden and the United States.

After a week of training sessions at nearby dams and lakes, the 150 competitors have been stepping out onto the ice in their rubber boots for the two-day championship.

Seventy-five anglers dug holes in the ice with hand augers, remaining bent over them for hours fishing with their small palm rods.

The aim is to catch as many fish as possible - mainly tiny perches and roaches.

In the five areas on the lake set aside for the competition, teammates and captains gather around to cheer the anglers on, alongside the referees and spectators eager to see the pros in action.

"The idea is to have more fish than anyone else as a team and be a world champion -- as simple as that. To find out if you are wiser than the fish," Finland's team captain Elisa Saarela told AFP.

The competitors may have been mostly catching fish that could fit in their palms, but Saarela says the smaller the fish, the bigger the achievement.

"When the fish is smaller, it's much harder to get it. A bigger fish is much more easy to catch. If you catch a big amount of small fish, you are very professional," Saarela explained.

But she says the best part of this unusual sport is being "out in the nature, in fresh air, with beautiful surroundings and seeing good friends from all over the world".

The new ice fishing world champion and the individual winner - the competitor who caught the most fish - will be crowned at the end of Sunday.