马绍尔群岛海域和吉尔伯特群岛海域黄鳍金枪鱼生物学特性比较

利用2006年10月至次年1月在马绍尔群岛海域与2009年10～12月和2010年11月至次年1月在吉尔伯特群岛海域延绳钓探捕所取得的黄鳍金枪鱼(Thunnus albacares)的生物学数据,应用统计学方法对两个海域的黄鳍金枪鱼生物学特性进行分析、比较。结果表明:(1)马绍尔群岛海域和吉尔伯特群岛海域黄鳍金枪鱼的优势叉长分别为120～140 cm和100～140 cm,平均叉长分别为(129±1.08)cm和(119±0.78)cm,差异性显著;(2)性别比例(雄性∶雌性)分别约为1.07∶1和1.40∶1,无显著性差异;(3)马绍尔群岛海域黄鳍金枪鱼的性腺成熟度高于吉尔伯特群岛北部海域,吉尔伯特群岛北部海域黄鳍金枪鱼的性腺成熟度高于南部;(4)摄食等级均以0和1级为主,其中马绍尔群岛海域分别占48.31%和35.96%,吉尔伯特群岛海域分别占27.91%和40.70%,无显著性差异;(5)两海域原条鱼重与叉长的关系无显著性差异;(6)马绍尔群岛海域的黄鳍金枪鱼可能是从吉尔伯特群岛海域洄游过去的。

Comparison of the biological characteristics of yellowfin tuna (Thunnus albacares) between Marshall Islands waters and Gilbert Islands waters

Based on the biological data of yellowfin tuna(Thunnus albacares) collected on board longliners "SLC719" and "SLC901" operating in Marshall Islands waters from Oct.27th,2006 to Jan.14th,2007 and Gilbert Islands waters from Oct.8th,2009 to Dec.21st,2009 and from Nov.26th,2010 to Jan.14th,2011,the yellowfin tuna’s maturity stages of the gonad,feeding intensity,sex ratio,fork length distribution,relationship between fork length(L) and round weight(WR),relationship between round weight(WR) and gilled and gutted weight(WG) were analyzed by statistics.The results indicated:(1) In Marshall Islands waters and Gilbert Islands waters,the dominant fork length of yellowfin tuna was from 120 cm to 140 cm(81.82%) and from 100 cm to 140 cm(87.92%) and the mean of fork length is 129±1.08 cm and 119±0.78 cm,respectively;The mean fork length in Marshall Islands waters was larger than that in Gilbert Islands waters;There were significant differences between them;(2) In both sea areas,the sex ratio(male∶ female) was 1.07∶ 1 and 1.40∶ 1,respectively;There was no difference between them;(3) The maturity stages of yellowfin tuna in Marshall Islands waters was higher than that of north Gilbert Islands waters;the maturity stage of yellowfin tuna in north Gilbert Islands waters was higher than that in south Gilbert Islands waters;there were significant differences between them;(4) The feeding intensity was dominant in the class 0 and class 1,42.86% and 39.29% for Marshall Islands waters,and 27.72% and 41.49% for Gilbert Islands waters;there was no significant difference between them;the prey biomass of yellowfin tuna in Gilbert Islands was as abundant as that in Marshall Islands;(5) By the linear regression,the relationship between WG and WR of yellowfin tuna was expressed by WG=0.905 8 WR in Marshall Islands waters and WG=0.850 4 WR in Gilbert Islands waters;there were significant differences between them;(6) By the power regression,the results showed that: the relationship between L and WR of yellowfin tuna was expressed by WR=2.296 9×10-4L2.477 2 for Marshall Islands waters and WR=2.643 7×10-5L2.928 6 for Gilbert Islands waters;there was no significant difference between them;(7) The yellowfin tuna in Gilbert Islands waters might migrate to Marshall Islands waters.