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

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). Divers may negatively affect underwater habitats. However, if effectively engaged, they can contribute to science, territorial management and more sustainable local economies. 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. 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. 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.