López-Ordaz Adriana, Ortaz Mario, Rodriguez-Quintal José G
Instituto de Biología Experimental, Universidad Central de Venezuela, Caracas, Venezuela.
Rev Biol Trop. 2009 Dec;57(4):963-75.
Seagrass beds are considered important feeding places for a variety of fish species characterized with complex trophic interactions. In this paper we described the trophic network of a fish community inhabiting a seagrass bed in the Venezuelan Caribbean. In addition, a consumption index (CI) for each prey ingested is proposed using two variables: abundance and consumption frequency. Eight samplings (at four time intervals: 6:00, 12:00, 18:00 and 24:00 hours) were done in August 2005 and January 2006. Fifty one fish species in 29 families were captured; Haemulidae was the most abundant. Crustacea was the most important food resource of the 28 food items identified. The relative importance of trophic guilds, considering abundance and taxonomic species richness, was: benthophagous>herbivorous>piscivorous. The features of the trophic network were: 1) high proportion of short chains (two links), 2) high number of intermediate species, 3) high consumption of benthos, 4) low CI values and 5) few species with a high number of linkages. Temporal (hourly and monthly) differences were obtained in fish species number (total, intermediate and top), total linkages, connectivity and maximal chain lengths. The connectance did not show significant temporal variation and it was similar to other environments with different species richness. In contrast, the connectivity was lower than the one reported for environments with low species richness. As in other reports, the temporal variation of the trophic parameters and the community structure was different. The values of CI for the different preys were low except for harpacticoid copepods and crustacean larvaes. The cluster value of CI was high for benthos (>80 %) and, in general, low for plankton and nekton preys. The seagrass bed studied was an important feeding place where the configuration of trophic network changed in different temporal scales and reflected the dynamic of the feeding relationships this fish community.
海草床被认为是各种具有复杂营养相互作用的鱼类的重要觅食场所。在本文中，我们描述了委内瑞拉加勒比地区一个栖息着鱼类群落的海草床的营养网络。此外，还使用丰度和消费频率这两个变量为每种摄入的猎物提出了一个消费指数（CI）。2005年8月和2006年1月进行了八次采样（在四个时间间隔：6:00、12:00、18:00和24:00）。捕获了29个科的51种鱼类；石鲈科是数量最多的。甲壳类是所确定的28种食物中最重要的食物资源。考虑到丰度和分类物种丰富度，营养类群的相对重要性为：底栖食性>草食性>食鱼性。营养网络的特征为：1）短链（两个环节）比例高，2）中间物种数量多，3）底栖生物消费量高，4）CI值低，5）具有大量连接的物种少。在鱼类物种数量（总数、中间物种和顶级物种）、总连接数、连通性和最大链长方面获得了时间（每小时和每月）差异。连通度没有显示出显著的时间变化，并且与具有不同物种丰富度的其他环境相似。相比之下，连通性低于物种丰富度低的环境所报告的连通性。与其他报告一样，营养参数和群落结构的时间变化是不同的。除了猛水蚤类桡足类和甲壳类幼虫外，不同猎物的CI值都很低。底栖生物的CI聚类值很高（>80%），总体而言，浮游生物和游泳生物猎物的CI值很低。所研究的海草床是一个重要的觅食场所，营养网络的结构在不同的时间尺度上发生变化，并反映了这个鱼类群落觅食关系的动态。
