Blue crabs are native to the western Atlantic and were introduced to European waters via ships ballast waters.
The Latin scientific name, sapidus, means 'good to eat'.
When cooked, the blue crab becomes red.
Lionfish come from the Indian Ocean but they are invading the Mediterranean.
The lionfish in the Mediterranean all come from a small number of individuals that crossed the Suez Canal from the Red Sea.
They first arrived in Cyprus in 2012 and now they are common there!
In the Caribbean, where they are also invasive, sharks are trained to eat lionfish.
Usually sharks avoid eating lionfish because they have stinging spines. But if you get them used to it, they get a taste for it, just as we do for spicy food!
You can tell male mussels from female mussels by the colour of their flesh. The females are bright orange and the males are more yellowish.
The mussel clings to rocks thanks to little strings called byssus. They are glued to the rock with a special mussel glue that can even cling to Teflon!
Mother-of-pearl, the material making the shell of mussels, is made of 99% chalk. But thanks to 1% of special mussel proteins and the way the mussel structures its shell, the shell is many thousand times stronger than chalk!