Dr. Giorgos Chatzigeorgiou and Ioannis Rallis from the Institute of Marine Biology, Biotechnology and Aquaculture, at the Hellenic Centre for Marine Research in Crete, are scientific divers who investigate 'Non-indigenous and Invasive Species in Ports and Marinas', despite the challenges of poor visibility, ropes, chains and unpredictable marine traffic. Their research shows a surprisingly high species richness in these extreme environments, but also a high number of non-indigenous spec...