ABSTRACT
Consumption of sea-urchin roe is a very ancient tradition for Japanese people which concern at least 5–6 species which can develop populations sufficiently dense to be exploited by the local fisheries. The demand for this luxury-food is so important that Japan has to import roe from sea-urchin populations living in areas where strong up welling dynamics occur, e.g. mainly from the eastern shallow waters of the Indo-Pacific ocean, at the end of summer and autumn. Unfortunatly these stocks appear already overfished. Then, the authors suggest to investigate the possibility of exploitation of two species which can be considered as intertropical, and the most common in the Indo-Pacific : Tripneustes gratilla (L.) and Echinometra mathaei (Blv.). T.g. is a phytophagous species which can develop dense populations within ecosystems where hermatypic corals predominate; its gonadic index (IG) reach up to 12–13. On the contrary, E.m. is a rustic species and largely ubiquist, and more or less omnivorous; in the other hand its gonadic index (IG) does not exceed 5–7. However when E.m. develops very dense populations, e.g. more than 10–20 (up to 100 ind.m−2), and in spite of its lower IG (e.g.3–4), it should be profitable for fishing activities. Prospecting another way to solve the problem of the present lack in sea-urchin roe, the authors recorded four sites in the Indo-Pacific where upwelling occur that can fertilize the shallow waters where edible sea-urchins live.
