Mediterranean sea cucumbers - Biology, ecology, and exploitation

The Mediterranean Sea is the largest enclosed basin on Earth. The basin geological history, biogeography, climate, and habitat heterogeneity have generated remarkable biological diversity, rendering the Mediterranean a biodiversity hotspot. Between 40 and nearly 200 ecosystems have been identified in this basin depending on definition criteria; key among them, both in functional and structural terms, is the endemic Posidonia oceanica seagrass meadows. The meadows are an important habitat for some sea cucumber species, because they produce large quantities of seagrass debris, a preferred food source for many deposit feeders. A total of 57 species of sea cucumbers have been reported in the Mediterranean, of which 21 (37%) are likely endemic. At least six species from the Mediterranean (Holothuria forskali, H. mammata, H. polii, H. sanctori, H. tubulosa, and Parastichopus regalis) are being exploited on a basin scale or are of interest for exploitation due to their biomass and accessibility. In this chapter, for each of these species, the biology, ecology, and fishery exploitation are presented in detail. Preliminary data and considerations for responsible fisheries management are also reported, based on the Italian stock assessment program.