Considerations on the intertropical edible sea-urchin populations in the Indo-Pacific

This chapter discusses the Indo-Pacific fauna mainly in the southern hemisphere, comparing the populations inhabiting the western Madagascar shores with those of New South Wales coasts and together some sites the hydrological and currents features are similar. Within this latitude range (i.e. 30”N-30”S) only few edible species develop sufficiently dense populations in some assemblages participating in the coral-reef complex, both barrier and fringing ones. In the Pacific Ocean, it seems that any sea-urchin was presently harvested for the market, even as regards Tripneustes gratilla due to its population density here was lower than in many places in the Indian Ocean. The populations of only two species such as Centrostephanus rodgersii and Heliocidaris tuberculata, also exist here with similar population density, that might be ascribed in part to a lower fertility of the water-column, in part to a lower development of coral-reef assemblages here.