What is the danger of reducing the trophic levels of marine systems?
Reducing the diversity and complexity of marine systems is an unraveling process that puts individual species at greater risk of local extinction. It causes changes that spread throughout the food web of the marine system. Energy enters marine ecosystem through the photosynthesis of plants. Energy from the sun is passed throughout food webs, from trophic level to trophic level. This energy transfer is not completely efficient but there is now evidence reductions in the average trophic level can actually reduce the efficiency of this energy flow. These changes may actually favour some groups of animals. Some people have linked the great increase in the abundance of jellyfishes in recent years with this loss of efficiency, caused by fishing down the food web. Ironically, man has adapted quite well. Whereas we used to focus our attentions primarily on larger fishes (ignoring now precious shellfishes and crustaceans), we now harvest smaller fish species. Not only are individuals within a s
