Reproductive investment, expressed in terms of fecundity and egg quality produced by individual female fish, varies among populations for many species, reflecting plasticity in life history strategies related to intraspecific density dependence or environmental variability. Fisheries scientists and managers have long sought to understand differences in Largemouth Bass Micropterus salmoides population dynamics, yet basic life history traits, such as variation in reproductive investment, remain largely unknown. We determined the fecundity–weight and ovary energy density–weight relationships (where fecundity indexes egg quantity and ovary energy density indexes egg quality) for Largemouth Bass populations from 19 Ohio reservoirs and examined factors that were correlated with population‐specific differences. We found that both relationships varied among reservoir populations, with some interannual variation in reservoirs sampled in multiple years. We then related fecundity and ovary energy density to (1) population characteristics, including population density (as indexed by standard shoreline boat electrofishing CPUE, fish/h) and growth (as indexed by the growth coefficient k from the von Bertalanffy growth function); and (2) reservoir characteristics, including reservoir size (as surface area) and productivity (as Secchi transparency depth). We found that populations with greater fecundity also exhibited greater ovary energy density, indicating that the quantity and quality of reproductive output were greater in some populations than in others. Populations with high reproductive investment were associated with low Largemouth Bass density, fast growth, large reservoir size, and high productivity (i.e., low Secchi transparency). The among‐population variation in reproductive investment provides evidence of density‐dependent control of fecundity and egg quality.

中文翻译：

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俄亥俄州水库大口黑鲈种群中生殖投资的变化

以个体雌鱼的繁殖力和卵品质表示的生殖投资，在许多物种的种群中各不相同，反映了与种内密度依赖性或环境变异性有关的生命史策略的可塑性。渔业科学家和管理人员一直在寻求了解在大口黑鲈差异大口黑鲈人口动态，但基本的生活史特征，例如生殖投资的变化，仍是未知之数。我们确定了俄亥俄州19个水库大嘴鲈种群的生殖力与体重和卵巢能量密度与体重的关系（生殖力指标卵数和卵巢能量密度指标卵质），并研究了与种群特异性差异相关的因素。我们发现两种关系在水库种群之间是不同的，并且在多年采样的水库中有一些年际变化。然后，我们将繁殖力和卵巢能量密度与（1）种群特征相关，包括种群密度（由标准岸线电钓鱼CPUE，鱼/小时指数）和生长（由生长系数k指数）来自冯·贝塔朗菲的增长函数）; （2）储层特征，包括储层大小（以表面积计）和生产率（以Secchi透明深度计）。我们发现，繁殖力较高的种群也表现出更高的卵巢能量密度，这表明某些种群的生殖产出的数量和质量要高于其他种群。生殖投资高的人口与大嘴鲈密度低，生长快，水库面积大和生产力高（即Secchi透明度低）相关。繁殖投资的种群间差异为密度和产卵量的密度控制提供了证据。