印度洋金枪鱼渔业平均营养级的长期变动

Long-term changes in the mean trophic level of tuna fishery in the Indian Ocean

利用印度洋金枪鱼委员会(IOTC)提供的数据,结合FishBase所提供的相关鱼种的营养级,分析了1950—2003年印度洋金枪鱼渔业平均营养级(TLi)的变动情况。结果表明:TLi于1950—1960年呈明显的下降趋势,1960—1980年呈波动上升趋势,1990年以后趋于稳定;TLi与金枪鱼渔业产量,于1950—1960年两者之间呈明显的负相关,1960—1970年随渔业产量的增加TLi也增加,1970—1980年两者之间没有明显的关系,1980—1990年两者之间呈明显的正相关,1990年以后随着产量的增加TLi趋于稳定;FIB指数于1951—1956年呈直线增长趋势,1957—1975年呈波动式增长,1976年以后基本上呈直线增长。

The fluctuation in mean trophic level （TLi ） of tuna fishery in the Indian Ocean was evaluated by the data provided by Indian Ocean Tuna Commission （IOTC） and integrated with related information on trophic level of selected fish species collected from Fishbase from 1950 to 2003. A significant decrease in TLi appeared in 1950＇s, fluctuated increase from 1960＇s to 1980＇s, and constant after 1990＇s. There was an inverse correlationship between catch of tuna fishery and TLi in 1950＇s, TLi increasing with increase in the catch in 1960＇s. There was no significant relationship between TLi and catch in 1970＇s. A positive correlationship between TLi and catch was observed in 1980＇s, TLi being stable after 1990＇s. Fishing -in -balance index （FIB） showed a straightly increasing trend from 1951 to 1956, a fluctuated increasing from 1957 to 1975, and a straightly increasing trend after 1976.