The production of Mediterranean bath sponges collapsed during the past century, as is shown by Tunisian catches, which fell from 108 tons in 1920 to 9 tons in 1988. A further illustration is provided by the well-known sponge-fishing island of Kalymnos, which lost about 90% of its active sponge-fisher population over the century between 1858 and 1967. What are the reasons for this dramatic decline of a once prosperous Mediterranean traditional fishery? What part of the decline can be attributed to the progressive reduction of the bath sponge stock, and what to a decreasing number of fishermen? How might this sponge fishery collapse be related to changes in uses, overfishing, and disease outbreaks triggered by climate events? How did sponge fishermen adapt to Regional Changes in the past? What is the future of such a fishery? What kind of guidelines can we provide for this fishery facing ongoing Regional Change?