Knowledge of the present status and future potential of the world's marine food resources is a key prerequisite to their ecological exploitation. Rationales for the exploitation of these resources are twofold. Most important is the expectation that more time to reduce human population growth—the ultimate goal—could be made available. Secondly, because fish and shellfish are typically high in their content of protein and low in fat, nutritional quality in the human diet can be improved through their increased use.
Fundamental to marine biological production are the phytoplankton populations which comprise the basis of the oceanic food-structure. This production involves the photosynthesis of organic matter by phytoplankton and the subsequent flow of this matter through the food-web. Spatial and temporal discontinuities in marine production are related to the patchy distributional pattern of phytoplankton and to natural fluctuations in oceanic populations due to geographically and temporally varying conditions. A review of past estimates of the potential marine yield suggests that there has been significant variation in the methodology employed to arrive at these estimates.
Much-improved management of the oceanic food resources is urgently needed. Present mismanagement of these resources includes chemical pollution and the overexploitation of several important fish-stocks, which together threaten the viability of marine life. On the positive side, the future potential of the overall marine food-resources appears to be considerably larger than the present yield. The current harvest can be augmented by further development of aquaculture and by the exploitation of unconventional species, both of which could offer a relatively untapped source of valuable protein. Thus, Man must quickly establish and implement a rational, global management plan for the world's oceans and control his own population numbers to ensure conservation of the marine food-resources.