Forage fishes have a cosmopolitan distribution and constitute key species in marine trophic webs throughout the world. We estimated the energy density of the Argentine Anchovy Engraulis anchoita, a key component of the base of the food web in a large fraction of the southwestern Atlantic Ocean. We also examined the relationships between energy density and different proxies (condition factor, fork length, and percent dry weight) and compared the relationship of energy density to percent dry weight for Argentine Anchovy to this relationship in other forage fishes. A regression model that includes percent dry weight and fork length was the best predictor for the energy density in this species. The Argentine Anchovy had similar energy density to percent dry weight to all species in the Engraulidae family (anchovies) and to most of the species in the Clupeidae family (sardines). Engraulidae species showed smaller mean energy density and smaller energy density to percent dry weight compared with the Clupeidae species. The difference in energy density between these two families could have direct implications on population dynamics of predators in oscillating sardine–anchovy systems or in regions where these two families are spatially segregated.

中文翻译：

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阿根廷An鱼（Engraulis anchoita）（西南大西洋的主要物种）的能量密度预测因子

饲料鱼具有世界性的分布，是全世界海洋营养网中的关键物种。我们估算了阿根廷An鱼Engraulis anchoita的能量密度，是西南大西洋大部分地区食物网基础的重要组成部分。我们还检查了能量密度与不同代理之间的关系（条件因子，货叉长度和干重百分比），并将阿根廷An鱼的能量密度与干重百分比的关系与其他饲用鱼的这种关系进行了比较。包括干重百分比和叉子长度的回归模型是该物种能量密度的最佳预测指标。En鱼科（an鱼）和all科（沙丁鱼）中大多数物种的阿根廷density鱼的能量密度和干重百分率相似。与gra科相比，科物种显示出较小的平均能量密度和相对于干重百分数的较小的能量密度。