西南大西洋阿根廷滑柔鱼生物学年间比较

Annual variability in biological characteristics of Illex argentinus in the southwest Atlantic Ocean

将2007年2—5月、2008年3—5月、2010年1—3月我国鱿钓船在西南大西洋公海海域采集的阿根廷滑柔鱼样本,比较其不同年间的生物学特性。结果表明,渔获物雌雄比为1.14—1.50:1;3a雌性个体的胴长(体重)分别为188—346mm(110—856g)、200—364mm(145—950g)、124—276mm(72—425g),雄性个体的胴长(体重)为178—298mm(102—703g)、193—314mm(145—680g)、104—335mm(70—374g)。2010年渔获个体明显比2007和2008年小。各年间及雌、雄个体间的体重与胴长关系均存在差异(P<0.001),渔获物中年间性成熟组成差异明显,此外各年3月份渔获个体也存在显著差异。雌、雄个体的胴长平均生长率分别为0.53—1.07 mm/d、0.47—0.68 mm/d,相对生长率分别为0.24—0.41%d-1、0.23—0.33%d-1;雌、雄个体的体重平均生长率在1.70—5.25 g/d、1.64—4.59 g/d,相对生长率分别为0.92—1.37%d-1、0.86—1.40%d-1。渔汛期间,胴长、体重与时间的关系均符合指数生长曲线,但生长指数年间差异明显。综合分析认为:2007年渔获物基本上为南巴塔哥尼亚种群;2008年以南巴塔哥尼亚种群为主,但也有少量较小个体的夏季产卵种群;2010年则以夏季产卵种群为主,并有少量的南巴塔哥尼亚种群。

Based on the samples taken from the Chinese squid jigging fishery in the high sea waters of Southwest Atlantic from February to May in 2007, March to May in 2008 and January to March in 2010, annual variability in biological characteristics of squid Illex argentinus were evaluated. For the sampling time periods, this study showed that the sex ratio （female versus males） of catch was between 1. 14-1. 50：1, and that the mantle length （body weight） of female squid ranged from 188 to 364 mm （110-856g）, 200-364mm （145-950g）, and 124-276mm （72-425g） respectively, and that the mantle length （body weight） of male squid ranged from 178-298mm （ 102-703g）, 193-314mm （145-680g） and 104-335mm （70-374g） , respectively. The sizes of catch in 2010 were much smaller than those in 2007 and 2008. The relationship between mantle length and body weight differed significantly between the sexes and among sampling time years （P 〈 0. 001 ）. Significant differences were also found in the composition of sexual maturity in the three years.Meanwhile the significant difference also existed in sizes of catch taken in March over the three years. The average growth rates of mantle length for females and males were 0. 53-1. 07 mm/d and 0. 47-0. 68 mm/d respectively, and the average instantaneous relative growth rates for females and males were 0. 24-0. 41% d^-1 and 0. 23-0. 33% d^-1. The average growth rate of body weight for females and males were 1. 70-5. 25 g/d and 1. 64-4. 59 g/d, respectively, and the average instantaneous relative growth rates for females and males were 0. 92-1. 37% d^-1 and 0. 86-1. 40% d^-1. The growth indices varied significantly among the years. The relationship between mantle length or body weight and time could be quantified by an exponential growth curve during the fishing seasons. In conclusion, the individuals of the catch in 2007 were from the South Patagonic Stock （SPS） ; the individuals of the catch in 2008 mainly consisted of SPS squid, but mixed with a small number of small individuals of the Summer-Spawning Stock （SSS） ; while the SSS made the major contributions to the catch in 2010 with the presence of a small number of SPS. This study suggests a large annual variability in key biological parameters of squid targeted by the Chinese squid jigging fishery in the Southwest Atlantic Ocean.