Fernandez-Delgado C, Rossomanno S
Zoology Section, Department of Animal Biology, Sciences Faculty, University of Cordoba, San Alberto Magno Avenue, Cordoba, 14004, Spain
J Fish Biol. 1997 Jul;51(1):80-92. doi: 10.1111/j.1095-8649.1997.tb02515.x.
Introduced Gambusia holbrooki in a natural lagoon of southern Spain consisted of two age groups: 1992 cohort, 7-11 months old and 1993 cohort, <4 months old. In the 1992 cohort, females grew even during the gestation period at about 0.30 mm day-1. In the 1993 cohort, females displayed a high growth rate (0.55 mm day-1) and reached reproductive size in a few weeks, but stopped growing when they matured. All the 1992 cohort reproduced from mid-May to mid-June, but only 50% of the 1993 cohort reproduced, from mid-August to mid-September. Reproducing females were significantly larger in the 1992 cohort (39.8 mm) than in the 1993 one (34.8 mm). The largest 1992 females cohort had reproduced previously; the 1993 cohort had not. The mean dry weight of intra-ovarian embryos decreased to a minimum immediately before birth. These metabolic costs represented 29.8 and 31.4% of the initial weights of the 1992 and 1993 embryos, respectively. Mean dry weight of full-term embryo was significantly higher in the 1992 cohort (0.80+/-0.129 mg; 95% CL) than in the 1993 one (0.70+/-0.086 mg; 95% CL). With more females in 1992, cohort fecundity was considerably higher (number of embryos=7151; 63%) than in the 1993 (4193; 37%) cohort. The population completed two generations each year (spring and summer). The spring stock grew slower than the summer one but continued to grow during the gestation period, reaching larger final lengths, with more synchronous reproduction and clearer evidence of a second reproductive event. Each reproductive stock displayed its own life-history characteristics, with significant differences between mean length of reproducing females, growth rate, mean brood size, offspring size, standard fecundity and minimum length at reproduction.
1992年组，7 - 11个月大；1993年组，小于4个月大。在1992年组中，雌性食蚊鱼在妊娠期仍以约0.30毫米/天的速度生长。在1993年组中，雌性食蚊鱼生长速度较快（0.55毫米/天），几周内就达到了生殖尺寸，但成熟后停止生长。所有1992年组的食蚊鱼在5月中旬至6月中旬繁殖，而1993年组只有50%的个体在8月中旬至9月中旬繁殖。繁殖期的雌性食蚊鱼，1992年组（39.8毫米）明显大于1993年组（34.8毫米）。1992年组中最大的雌性食蚊鱼之前已经繁殖过；1993年组则没有。卵巢内胚胎的平均干重在出生前立即降至最低。这些代谢成本分别占1992年和1993年胚胎初始重量的29.8%和31.4%。1992年组足月胚胎的平均干重（0.80±0.129毫克；95%置信区间）显著高于1993年组（0.70±0.086毫克；95%置信区间）。由于1992年组的雌性个体更多，其种群繁殖力显著高于1993年组（胚胎数量 = 7151；63%）（1993年组为4193；37%）。该种群每年完成两代繁殖（春季和夏季）。春季种群生长速度比夏季种群慢，但在妊娠期仍持续生长，最终体长更大，繁殖更同步，且有更明显的第二次繁殖迹象。每个繁殖种群都有其自身的生活史特征，在繁殖期雌性食蚊鱼的平均体长、生长速度、平均窝卵数、后代大小、标准繁殖力和繁殖时的最小体长等方面存在显著差异。
