Thursday, October 16, 2014

'Tropical' crab Percnon gibbesi at HCMR Attika Greece

OK summer is over but the place looks to me like a tropical paradise: Our institutes' backyard.

October 16th 2014 HCMR Anavissos Attika 

Went out for a quick snorkel at our backyard Aegean rocky bay this evening. This place is only about 50 meters from my work office at HCMR, so while others may smoke or flirt in the Cafeteria I can slip into a comfortable autumn sea. No one is out there. Its a great way to wake-up a bit after so much office work...

This summer I have been noticing the nimble spray crabs Percnon gibbesi  (Grapsidae) and wanted to just take some snapshots. These are fantastic super thin, fairly large and fast crabs. They seem so tropical to me. And they are aliens: first recorded in Greece in 2004 and now established in many areas in the southern half of the Aegean and in the Ionian. They are considered one of the fastest spreading invasives (first Mediterranean record was in 1999). Originally they are from the warm temperate and tropical Atlantic and Eastern Pacific. In many southern Greek coasts the desities of these fascinating creatures are already high. Today, I easily counted about 15 crabs in a beach-rock shoreline of about 100 m. distance. Small ones and larger ones also. They are vegetarians picking up algae in super-quick mechanical action. I also found one or two native crabs. Fascinating Mediterranean invasion ecology!


Super close-up of Percnon gibbesi
Feeding on algae rapidly amongst the boulders.
Upside down, fast and nimble like a cockroach!
Exotic colours, elegant - outlandish and alien.
Native crab, perhaps in the genus Pachygrapsus. Are they competing?