“It’s dirty, hot work picking up blue crabs (Callinectes sapidus). They like murky water, and you need special clothing and equipment to wade through the swampy lagoon here in the Palud – Palù ornithological reserve in Pula, Croatia. It was the end of a long day in September last year when this photo was taken, and I was hot and sweaty under that special clothing. And once you find a crab, you have to be careful not to injure yourself picking it up: either on its sharp lateral spine, or from its very strong claws.

I catch the crabs because they are an invasive species, and because it’s my job: as well as working as a biotechnologist, I’m a fisher. Blue crabs are native to Chesapeake Bay in the eastern United States, and they probably made their way here on a ship in the early twentieth century.

There has been a large population in the Po river estuary for many years — but a combination of factors, including global warming, has seen them spread down the Adriatic coast since 2022.

The crabs are a problem because they eat the bivalves, fish and other crabs that make up the diets of many of the endangered seabirds here at the nature reserve — without that vital source of food, these birds will be even more threatened and we’ll face a serious loss of biodiversity.

My colleagues and I at the Juraj Dobrila University of Pula are encouraging local people to eat the crabs, which are sold at the markets. We’ve held awareness activities since long before 2022, in anticipation of the explosion of the invasive population. I know more and more people who collect blue crabs for food.

We’re losing the battle against climate change: the changes are too fast and we are far too slow to adapt to them. But I hope by better understanding the biological capital we have available here, we can build a better relationship with nature.”