中文摘要：

基于2008年9月至2009年4月在印度洋中南部水域金枪鱼延绳钓渔场收集的数据,研究分析和比较了3种钓钩钩型（传统金枪鱼钩、＂J＂形钩和圆形钩）的渔获效益及对钓捕对象的选择性。结果表明：（1）从渔获种类上看,大眼金枪鱼和大青鲨金枪鱼钩钓获比例最高,＂J＂形钩和圆形钩的钓获比例相当;而长鳍金枪鱼则为金枪鱼钩钓获比例最高,其次为＂J＂形钩和圆形钩。（2）大眼金枪鱼存活率以金枪鱼钩最高,＂J＂形钩最低;长鳍金枪鱼则为＂J＂形钩稍高于圆形钩,金枪鱼钩最低;大青鲨则以圆形钩最高,＂J＂形钩最低。（3）＂J＂形钩钓获的长鳍金枪鱼和鲨鱼平均叉长较金枪鱼钩和圆形钩稍大;而金枪鱼钩钓获的大眼金枪鱼平均叉长较圆形钩和＂J＂形钩稍大。（4）3种钩型钓获的长鳍金枪鱼、大眼金枪鱼和大青鲨叉长分布均不存在显著性差异。

英文摘要：

Based on the data collected from the fishing ground of tuna longliners in the Southern-central Indian Ocean during September 2008 to April 2009,the present study compares and analyzes the catchability and selectivity to hooking species for 3 hook types（traditional tuna hook,＂J＂-type hook and circle hook）.The results show that（1） for traditional tuna hook,the proportion of bigeye tuna（Thunnus obesus,BET）and blue shark（Prionace glauca,BLS）is higher than other species in the catch composition and ＂J＂-type hook and circle hook have a similar hooking proportion for the above two species,however,for albacore（Thunnus alalunga,ALB）,the traditional tuna hook has the highest hooking proportion and followed by ＂J＂-type hook and circle hook.（2） the traditional tuna hook has the highest survival rate and the ＂J＂-type is lowest for BET,the survival rate of ＂J＂-type hook is slightly higher than that of circle hook and the traditional tuna hook is the lowest for ALB,the survival rate of circle hook is highest and followed by traditional tuna hook and ＂J＂-type hook for BLS.（3） the average fork length（FL）of ALB for ＂J＂-type hook is slightly larger than that of traditional tuna hook and circle hook,traditional tuna hook is larger than circle hook and ＂J＂-type hook for BET and ＂J＂-type is larger than circle hook and traditional tuna hook for BLS.（4） significant difference has not been found for the FL distribution of ALB,BET and BLS for 3 hook types.