EXPLOITATION AND CONSERVATION OF ECHINODERMS

The phylum Echinodermata contains some of the most charismatic benthic marine invertebrates and has become a symbol of marine life. However, growing global pressures on the collection of echinoderms for various commercial enterprises have put these enigmatic invertebrates under threat. This review summarises the demands on echinoderms from commercial fisheries, aquarium and souvenir trades, as part of the global search for bioactive compounds from marine organisms, and as experimental models in evolution and toxicology, and highlights the urgent need for an integrated global strategy for their protection and conservation. Sea urchins and sea cucumbers are fished commercially worldwide. Increased landings, limited information on population biology and lack of stringent management of the fisheries have resulted in a global decline of populations. In addition to being a target species for commercial fishing, many echinoderms form part of the significant by-catch produced from the general use of fishing hardware. Even when they are not caught directly, echinoderms may be damaged to varying degrees as the gear passes over them and may be affected indirectly by the physical disturbance caused by fishing gear to the seafloor. Echinoderms are gaining popularity with aquarists and account for about 17% of the global trade. Pharmaceutical companies are constantly screening marine organisms for biochemical compounds for potential use in medicine, traditional healing and industrial applications. The marine bioprospecting industry is not regulated and, although at an early stage of development, the huge potential of echinoderms to provide bioactive products highlights the need for urgent action to regulate this kind of activity. Echinoderm embryos and larvae have been used as experimental model systems in several lines of research for more than a century, leading to significant advances in the areas of developmental biology, cell biology and immunology. In addition, echinoderms are well known for their striking regenerative capacity and have provided a valuable experimental model to identify the genes involved in the process of neural regeneration. Sea urchin gametes, embryos and larvae have also been used for fast, low-cost and reliable screening of toxic substances, and for detailed studies of their mechanism of action. One way to mitigate the commercial exploitation of wild echinoderm stocks is to develop laboratory culture methods to produce individuals for reseeding exploited populations and this is being done with sea urchins and sea cucumbers. However, releasing large numbers of captive-bred animals into the wild will undoubtedly affect the genetic composition of local populations, giving rise to important ethical issues related to the loss of a genetically unique wild stock. To aid conservation, it is necessary to improve the collection of data to quantify the extent of harvesting echinoderms and to document the location and catch data by species. It is also necessary to develop a global database of echinoderm species to summarise information on biology, ecology, threats, monitoring and conservation. Beyond increasing the number of echinoderm species to be protected, it is important to improve the conservation management of already protected species.