Within a population, larger individuals tend to have higher fecundity and produce higher quality eggs. For this reason, larger, older females often disproportionately contribute to recruitment. However, increases in body size and age have also been shown to correlate with increased bioaccumulation of environmental contaminants, which negatively impact reproduction and larval survival. In this study, we tested for maternal age and size effects on fecundity, egg size and quality, contaminant body burden, and maternal transfer in Alligator Gar Atractosteus spatula to assess the potential for contaminant bioaccumulation to offset reproductive benefits of large females. We measured fecundity and egg quality (via lipid content) as well as tissue concentrations of mercury, polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) in female Alligator Gar from the Trinity River, Texas. Fecundity was positively correlated with body size, but egg lipid was not significantly correlated with body size or with fecundity. Total mercury (THg) in both liver and muscle was positively correlated with maternal body size, and egg THg was positively correlated with maternal body size and liver THg. All liver and egg samples contained detectable levels of PCBs and OCPs, which were positively correlated with body size. Concentrations of PCBs and OCPs were positively correlated between tissues for each female, with egg concentrations being generally higher than liver concentrations. Based on concentrations of Hg, PCBs, and OCPs known to cause biological impairment in adult and larval fishes, the concentrations observed in this study suggest that adult reproductive function and behavior—as well as egg hatching success, larval development, and survival—could be compromised. Our results provide data that are relevant for managing the lower Trinity River Alligator Gar population and also serve as a case study demonstrating that the reproductive benefits of larger, older females may be eroded by contaminant accumulation and maternal transfer.

中文翻译：

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污染的身体负担和母体转移可能会侵蚀大雌性的种群贡献：以扬子鳄为例

在种群中，较大的个体倾向于具有较高的繁殖力并产生较高质量的卵。因此，较大，较大的女性通常不成比例地贡献力量。但是，还表明，体型和年龄的增长与环境污染物的生物积累增加有关，这对繁殖和幼体存活产生负面影响。在这项研究中，我们测试了产妇的年龄和大小对产卵力，卵子大小和质量，污染物的身体负担以及扬子鳄抹刀的产妇转移的影响。评估污染物生物蓄积的潜力，以抵消大雌性的生殖效益。我们测量了得克萨斯州三位一体雌性鳄鱼Gar中的繁殖力和卵质量（通过脂质含量）以及汞，多氯联苯（PCB）和有机氯农药（OCP）的组织浓度。生殖力与体重呈正相关，但卵脂与体重或生殖力无显着相关。肝脏和肌肉中的总汞（THg）与孕妇体型呈正相关，鸡蛋THg与孕妇体型和肝THg呈正相关。所有肝脏和鸡蛋样品均含有可检测水平的PCBs和OCP，与人体大小呈正相关。每个女性的组织之间PCB和OCP的浓度呈正相关，鸡蛋的浓度通常高于肝脏的浓度。根据已知会导致成年和幼体鱼类生物受损的汞，多氯联苯和OCP的浓度，本研究中观察到的浓度表明，成年生殖功能和行为以及卵孵化成功，幼体发育和生存可能妥协。我们的结果提供了与管理三位一体河短吻鳄Gar鱼种群相关的数据，并作为案例研究表明较大的老年雌性动物的繁殖效益可能会因污染物积累和母体转移而受到侵蚀。在这项研究中观察到的浓度表明，成年生殖功能和行为以及卵孵化成功，幼体发育和生存可能受到损害。我们的结果提供了与管理三位一体河短吻鳄Gar鱼种群相关的数据，并作为案例研究表明较大的老年雌性动物的繁殖效益可能会因污染物积累和母体转移而受到侵蚀。在这项研究中观察到的浓度表明，成年生殖功能和行为以及卵孵化成功，幼体发育和生存可能受到损害。我们的结果提供了与管理三位一体河短吻鳄Gar种群有关的数据，并且还作为案例研究表明，年龄较大的雌性动物的繁殖效益可能会受到污染物积累和母体转移的侵蚀。