水丰水库的池沼公鱼生物学
THE BIOLOGICAL ASPECTS OF POND SMELT (HYPOMESUS OLIDUS (PALLAS)) IN THE SHUI FENG RESERVOIR
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摘要: 本文报道了1942年横断鸭绿江而成的水丰水库的池沼公鱼生物学,内容包括性状变异、年龄和生长、食性、繁殖、群体结构、群体消长变化及渔业利用。水丰水库的池沼公鱼一龄体长(到尾叉的体长,后同)74毫米,体重3克;二龄体长99毫米,体重6.5克。体长体重关系式:logW=2.5306logL-1.7590。主要以浮游动物为食,但不同栖息地点食物组成有明显差异。一龄即达性成熟;性比为1♀:1.24♂;个体繁殖力905—19051粒,平均4330粒;个体繁殖力Y(百粒鱼卵)与体长L(厘米)的相关方程式为Y=58.4860L-402.7606;群体增殖速度(Vp)等于1494;4至5月在水库岸边产卵,卵粘性,水温10—15℃,约经12天孵出仔鱼。群体由1—3龄3个龄组组成,1321尾标本的平均年龄为1.15;65.1—80毫米体长组的个体为主要渔获对象,占整个渔获的65.5%。池沼公鱼是目前水丰水库第一位的经济鱼类,1982年鱼产量120万斤,占总鱼产的57.8%。Abstract: 1. The pond smelt in the Shui Feng Reservoir has more scales along the lateral line, more gill rakers and more vertebrae than those in other parts of the world (North America, Soviet Russia, Japan, and Korea), but less branched rays in the dorsal, anal and pectoral fins than those in Korea.2. The scale has been used for age-determination; annulus on the scale is characterized by a "check". The fish is about 74 mm in fork length (body length measured from tip of snout to the fork of caudal) and 3g in body weight when one year old; 99 mm and 6.5 g at 2 years of age. The regression equation of body weight (W) and fork length (L) may be expressed as log W=2.5306 log L—1.7590.3. The pond smelt is an omnivorous fish which feeds mainly on zooplanktion (Cladocerans and Copepods, etc.); the components of its food vary with habitats.4. First maturity of this fish is reached at 1 year old. The overall sex ratio in 1000 specimens examined was 446 females to 554 males, or 1♀: 1.2♂, but specific ration varied markedly with habitats. The individual absolute fecundity varied from 905 to 19051, with 4330 eggs on average. Its relation to the fork length may be expressed as Y=58.4860 L—402.7606 (Y—absolute fecundity in unit of 100 eggs, L—fork length in cm). The population fecundity index is 1871; the generative rate of population is 1494 females per "primary female". Spawning takes place in littoral areas of the reservoir in April or May. The eggs are adhesive, and hatch in about 12 days when water temperature ranges from 10° to 15℃.5. The structure of population of pond smelt is simple: there are three year classes in all population, the average age of 1321 specimens being 1.15 years. Body-length (fork length) groups ranging from 65.1 to 80 mm were dominant in that batch of sample (65.6%).