remote sensing may be particularly useful in the Mediterranean.
Few data are available on aspects such as trends in fishing techniques, employment levels and productivity. Those which are available are not particularly reliable. For example, productivity (measured, for example, as landings/fisherman/year) can be a misleading indicator because, although the total catch of a fleet may be increasing, productivity and catch per unit effort (CPUE) may be decreasing as fish stocks decline because of overexploitation. This is attributable partly to the lack of international standardisation on data collection and parameter definition (Cross, 1989).