Bath sponges from a marine protected area in the Aegean Sea

Diversity and density of bath sponges have been investigated in eleven localities inside and outside the area of the National Marine Park of Alonissos and Northern Sporades (NMPANS). The species Hippospongia communis (Lamarck, 1814) and Spongia officinalis (Linnaeus, 1759) were recorded. Dense populations of the latter, consisting of moderate-sized individuals, were detected exclusively in the core of the Marine Protected Area (MPA). Considering the dramatic decline of Mediterranean commercial sponge populations during the last 20 years, due to the combined effects of successive disease outbreaks and unregulated fishing activities, the remarkable sponge abundance recorded suggests that protection conditions may be considerably in favour of the viability of sponge populations.