热带大西洋公海锯鳞四鳍旗鱼生物学与钓捕深度研究

Biological Characteristics and Fishing Depth of Longbill Spearfish in High seas of Tropical Atlantic Ocean

根据2007年—2010年间两个航次的调查采集的热带大西洋公海海域(05°37′N^14°59′N,29°00′W^40°54′W)金枪鱼延绳钓兼捕的锯鳞四鳍旗鱼(Tetrapturus pfluegeri)渔业和生物学数据,研究了锯鳞四鳍旗鱼的长度组成、各长度之间和长度重量之间关系、性比、性腺成熟度及性腺指数。研究表明,锯鳞四鳍旗鱼的兼捕率为0.06170尾/千钩,雌雄下颌叉长(LJFL)分布不存在显著差异(K-S test,P>0.05)。雌雄锯鳞四鳍旗鱼下颌叉长(LJFL)与下颌体长(LJPCL)、下颌全长(LJTL)的关系呈线性显著相关(t-test,P<0.01),关系方程分别为:LJPCL=0.9065LJFL+4.5299;LJTL=1.0606LJFL+10.303。锯鳞四鳍旗鱼下颌叉长(LJFL)与体重的关系呈对数线性显著(t-test,P<0.01),关系方程为:RW=5.9162×10^(-6) LJFL2.9292。雌雄锯鳞四鳍旗鱼性比为1:1.33,雌性锯鳞四鳍旗鱼性腺成熟度以Ⅴ期占优势,平均性腺指数为1.11;雄性锯鳞四鳍旗鱼性腺成熟度以Ⅰ期占优势,平均性腺指数为0.16。兼捕的锯鳞四鳍旗鱼中有70%是在300m以上水层钓获的。

Based on fisheries and biological data of longbill spearfish（Tetrapturus pfluegeri）by two scientific observer surveys in high seas of tropical Atlantic Ocean（05°37′N～14°59′N,29°00′W～40°54′W）by the tuna longline fishery targeting bigeye tuna during 2007～2010,the biology of longbill spearfish is studied.The result indicates that the catch rate of longbill spearfish is 0.06170 per thousand hooks,the distribution of lower jaw fork length（LJFL）between female and male do not exist significant differences（K-S test,P〈0.05）.There are significant linear relationships between LJFL and lower jaw precaudal length（LJPCL）and between LJFL and lower jaw total length（LJT L）for longbill spearfish respectively（t-test,P〈0.01）,and the equations separately for LJPCL=0.9065LJFL＋4.5299,LJTL=1.0606LJFL＋10.303.There are significant log-linear relationships between LJFL and round weight（RW）for longbill spearfish（t-test,P〈0.01）,the equations for RW=5.9162×10-6 LJFL2.9292,sexratio of female and male for longbill spearfish is 1：1.33,gonadal maturity for female longbill spearfish dominates by V period and the mean gonosomatic index is 1.11,while gonad maturity for male longbill spearfish dominates by I period and the mean gonosomatic index is 0.16.70% of longbill spearfish are caught at 0～300mdepth layer.