黄海南部和东海小黄鱼产卵亲体分布特征与繁殖力的研究

Study on the distribution characteristics and fecundity of spawning stock of Larimichthys polyactis in the southern Yellow Sea and the East China Sea

根据2007年4月在黄海南部和东海进行的底拖网调查资料,分析了小黄鱼产卵亲体空间分布和分布海域的环境特征,以及小黄鱼个体繁殖力及其与体长、体重的关系等。结果表明,目前在近海海域和外海海域均有小黄鱼产卵亲体分布;产卵亲体分布海域的水温分布范围为9.77～18.85℃,平均13.46℃;盐度分布范围为31.59～34.65,平均为33.46;分布水深范围为13.21～104.67m,平均为57.56m;小黄鱼绝对繁殖力范围为2753～46657粒/尾,平均为15676粒/尾,体长相对繁殖力(FL)范围为21～323粒/mm,平均为113粒/mm,体重相对繁殖力(FW)范围为85～1307粒/g,平均为360粒/g;卵径大小范围为0.48～1.15mm,平均0.809mm。与历史资料相比较,小黄鱼产卵亲体分布范围已经扩大,产卵亲体分布海域的环境特征已经改变,相对繁殖力也显著提高,卵径变小。这些变化是小黄鱼本身对环境压力产生的一种适应性反映,也是小黄鱼为延续种群所采取的一种生存策略。

Based on the data collected from bottom trawl survey conducted in the southern Yellow Sea and the East China Sea in April 2007, the paper analyzed regional distribution of the spawning stock of small yellow croaker, environmental characteristics of the spawning ground and the relationship between the absolute individual fecundity and body size （weight and length）. The results indicated that the spawning stock of small yellow croaker inhabited in both shallow sea area and deep sea area. The ranges of temperature, salinity and depth of the spawning ground were 9.77 - 18.85 ℃, And the mean of temperature, salinity and depth of the 31.59 - 34.65 and 13.21 - 104.67 m, respectively. spawning ground were 13.46 ℃, 33.46 and 57.56 m, respectively. The mean of absolute individual fecundity of small yellow croaker was 15 676 eggs/ind. , with a range of 2 753 -46 657eggs/ind. ; the mean of relative individual fecundity （FL） was 113 eggs/mm, with a range of 21 - 323 eggs/mm ; the mean of relative fecundity （ Fw ） was 360 eggs/g, with a range of 85 - 1 307 eggs/g. The mean of egg diameter was 0.809 mm, with a range of 0.48 - 1.15 mm. Through comparing the present results with the historical data, the following changes were detected： the distribution area of the spawning stock of small yellow croaker extended; the environmental characteristics of the spawning changed ground obviously; the relative individual fecundity increased significantly; and the egg diameter decreased. All of these changes were due to the adaptability reflection of small yellow croaker to the environmental pressure, and they are helpful for small yellow croaker to promote its population.