Invasion of crabs: alien species go from pest to profit – a photo report

It can take Nabil a whole day to free the crabs entangled in his fishing nets. It is slow and meticulous work. In 2014, fishermen like Nabil began noticing large numbers of blue swimmer crabs (Portunus segnis) off Tunisia, particularly in the Gulf of Gabes on the country's east coast.< /p>

No one knows how the crabs arrived in the Mediterranean Sea from their native Indian Ocean, whether they migrated through the Suez Canal or were inadvertently transported on ships. But many researchers believe the climate crisis has helped the species spread as sea temperatures rise north of their normal range.