Saat Toomas, Lauringson Gustav, Lees Janek
Institute of Zoology and Hydrobiology, University of Tartu, Vanemuise Street, Tartu, Estonia.
Folia Biol (Krakow). 2003;51 Suppl:193-7.
Reproduction of the stone loach was investigated in two rivers of northwestern Estonia (Vääna and Maidla, 59 degrees N). Loaches in the Vääna River were slow growing and males prevailed among older fish; in the Maidla River loaches were fast growing and females dominated among older fish. Reproduction indices (age at maturation, duration of the spawning season, number of egg batches, fecundity, oocyte diameter, annual dynamics of gonadosomatic index and oocyte diameter) of comparably sized loach of Vääna and Maidla were similar and intermediate between more southern and more northern populations. Female investment in offspring (measured as the volume of spawned eggs) in Estonia was close to that in England; however, energy was invested in a smaller number of larger eggs (larvae). Our results confirm earlier data on the remarkable variation of life history patterns of the stone loach and indicate clinal variation of several reproduction indices along a north-south axis.
在爱沙尼亚西北部的两条河流（瓦埃纳河和迈德拉河，北纬59度）中对石鳅的繁殖情况进行了调查。瓦埃纳河中的石鳅生长缓慢，在年龄较大的鱼中雄性占优势；迈德拉河中的石鳅生长迅速，在年龄较大的鱼中雌性占主导地位。瓦埃纳河和迈德拉河中等大小石鳅的繁殖指标（成熟年龄、产卵季节持续时间、卵批次数量、繁殖力、卵母细胞直径、性腺指数和卵母细胞直径的年度动态）相似，且介于更南部和更北部的种群之间。爱沙尼亚雌性对后代的投入（以产出卵的体积衡量）与英国相近；然而，能量被投入到数量较少但更大的卵（幼体）中。我们的结果证实了早期关于石鳅生活史模式显著变化的数据，并表明几个繁殖指标沿南北轴呈渐变。
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