Changes in the marine trophic index of Chinese marine area

Abstract

Using the fishery catches and landings data from Food and Agriculture Organization of the United Nations (FAO) Fishery Statistics (1950 to 2011) for 129 marine species, we analyzed changes in the trophic index of captured species in China (including 4 sea areas: Mainland, Taiwan, Hong Kong and Macau). The results showed the following: the marine trophic index remained stable from 1950 to 1974, fluctuating around 3.45, then declined to 3.35 during the period 1975-1978, declined again sharply to 3.25 between 1982 and 1987, remained stable in the following 10 years, and then increased gradually to 3.34 from 1997 to 2011. Comparing to global marine trophic index, China's marine trophic index was higher than the global level be- fore 1984, but became lower after 1984. Comparing the contributions of the 4 main biological groups used in the calculation of the index showed that fish species contributed the mostly at 73.1-85.8%, crustaceans con- tributed 9.2-15.5%, molluscs contributed 3.3-11.6%, and other invertebrates contributed less than 1.8%. The general decline we observed in China's marine trophic index is associated with shifts in fishery catches from benthic fishes with a long lives and high trophic levels, to invertebrates and pelagic fishes with short lives and low trophic levels. Increasing Chinese marine trophic index from 1997 to 2011 may be attributed to a se- ries of fishery management countermeasures, including new fishing permits regulations, closed fishing sea- sons, zero and negative growth plans for marine fishery catches and landings, artificial breeding and