The blue crab's colourful claws are pretty - but dangerous: ripping up fishing nets and upsetting ecosystems off Albania's coast, the invasive species is a source of daily anguish for Balkan fishermen struggling to make ends meet.

The crab "takes our daily bread and even the fish in the nets... there is nothing to sell," says Besmir Hoxha, 44, pulling one crab's blue pincers off a small fish crushed in his net.