An assessment of “fishing down marine food webs” in coastal states during 1950–2010

Mean trophic level of fishery landings (MTL) is one of the most widely used biodiversity indicators to assess the impacts of fishing. Based on the landing data compiled by Food and Agriculture Organization combined with trophic information of relevant species in FishBase, we evaluated the status of marine fisheries from 1950 to 2010 for different coastal states in Pacific, Atlantic and Indian Oceans. We found that the phenomenon of “fishing down marine food webs” occurred in 43 states. Specifically, 27 states belonged to “fishing-through” pattern, and 16 states resulted from “fishing-down” scenario. The sign of recovery in MTL was common in the Pacific, Atlantic and Indian Oceans (occurred in 20 states), but was generally accompanied by significantly decreased catches of traditional low trophic level species. In particular, 11 states showed significant declining catches of lower trophic levels. The MTL-based assessment of “fishing down marine food webs” needs to be interpreted cautiously.