Description: The artisanal fi shery for Spondylus has a very long tradition in Ecuador but developments in recent years have made it an excellent example of the rapid overharvesting of a Latin American shellfi sh fi shery. In reaction to the declining population status, the Ecuadorian government enacted an offi cial ban on the fi shery in October 2009. The ban is intended to be kept in place at least until there is scientifi c information regarding stock status and basic population parameters that are necessary for a sustainable use of the resource. This study aims to provide the necessary knowledge base to develop a sustainable management program for Ecuadorian Spondylus stocks in the future. Our fi ndings suggest that current population densities will not allow for a recovery without additional measures to support such recuperation. Nevertheless, the parameters we have calculated for growth and fecundity suggest that exploitation of Spondylus as a resource is generally possible when undertaken with caution. Under a precautionary approach it is crucial for a future management program to monitor densities of individuals closely, as this study identifi ed recruitment failure as the main factor that has contributed to the collapse of the fi shery in the past. Restoration efforts would be of high value for the local ecosystem as this study has also shown that Spondylus contributes signifi cantly to the native biodiversity. Their shells provide a three dimensional habitat for a variety of drilling and non-drilling species that are not present without them, thus making Spondylus an important foundational species. Artisanal fi sheries make a signifi cant contribution to satisfying the increasing global demand for protein. It is dangerous to assume, that these fi sheries operate sustainably per se and it is crucial to ensure that they do in the future. Sustainable solutions for artisanal overfi shing are urgently needed, because tropical coastal communities are highly dependent on their local resources for their livelihoods and nutrition. The tools for successfully managing a common pool resource such as Spondylus through a comanagement system are known – we hope these are used in the future in conjunction with the fi ndings of this study to prevent this iconic genus from disappearing.

Description: In May 2009, we studied the bivalve Spondylus crassisquama and its relevance for macrobenthic biodiversity off the north Ecuadorian coast. We found that the large and heavy shells offer an exclusive substrate for numerous epibiont species and highly specialized carbonate-drilling endobiont species (71 species in total), which is a distinctly different and much more diverse habitat than the surrounding sandy bottoms (13 species, 4 of them found in both habitats). This is reflected by a Bray–Curtis dissimilarity index of 0.88. We discuss in detail the live habits of all 9 species of drilling endobionts that we found, and conclude that these can be seen as true mutualists, with the exception of boring sipunculids and bivalves. To further illustrate this complex co-existence, we visualize and quantify for the first time the tremendous effects of boring organisms on the shell structure of S. crassisquama by means of magnetic resonance imaging and a video appendix is provided.