Diving for science - science for diving: volunteer scuba divers support science and conservation in the Mediterranean Sea

1. Recreational diving engages 20 million people worldwide. Most of the literature refers to tropical destinations but at least 1 million dives per year take place in Mediterranean marine protected areas ( MPAs). 2. Divers may negatively affect underwater habitats. However, if effectively engaged, they can contribute to science, territorial management and more sustainable local economies. 3. During 2006- 2014, volunteers trained by the not- for- profit organization Reef Check Italia ( RCI) completed 24 714 observations and 2417 dives in six Mediterranean countries, contributing to a dataset that supports scientific papers about climate change, rare and non- indigenous species ( NIS), and informs MPA management decision- making. 4. The wide range of opportunities offered by this dataset is illustrated with two examples relevant to marine conservation in the context of MPA management. They concern: ( i) the spread of the NIS Caulerpa cylindracea along the Ligurian coasts, with a focus on Portofino MPA, and ( ii) the distribution and abundance of protected species in the Portofino MPA. 5. A diver- focused survey showed that RCI volunteers are highly committed, and that participation in RCI activities has led to a better understanding of, and a sense of stewardship towards, favoured dive sites and the marine world. Knowing who volunteers are, and why they volunteer in their favourite sector, is crucial to designing citizen- science based projects able to achieve their multiple goals. Copyright # 2016 John Wiley & Sons, Ltd.