Fundación Colombiana Para la Investigación y Conservación de Tiburones y Rayas SQUALUS, Carrera 79 No. 6-37, Cali, Colombia.
J Fish Biol. 2012 Apr;80(5):1563-79. doi: 10.1111/j.1095-8649.2012.03239.x.
Sexual, ontogenic and temporal effects in the diet of Dasyatis longa were evaluated to determine feeding habits and trophic ecology. Numeric indices and the index of relative importance were applied to establish the feeding strategy of the species. Independence of the diet with respect to sex, dry or rainy season and size was evaluated with contingency tables, correspondence analysis and multivariate analysis (MANOVA). The trophic relationships of D. longa (by sex and size intervals) were determined using Levin's niche breadth index and the Pianka's diet overlap index and their significance was determined by null models. The trophic level for each size interval and the species was also calculated. Dasyatis longa showed a narrow niche breadth feeding mainly on shrimps and fishes and its diet was dependent on size, but not on sex or season. Juvenile individuals (class I) fed on shrimps, sub-adults (class II) on fishes and adults (class III) on stomatopods. Significant overlaps between size classes I and II and classes II and III were found. The trophic level shows D. longa to be a secondary or tertiary consumer. Due to considerable fishing pressures on shrimps, the principal prey of D. longa, it will be important to determine their ability to adapt to changes in prey populations.
评估了长尾魟的性成熟、个体发育和时间效应在饮食中的作用，以确定其摄食习惯和营养生态。数值指数和相对重要性指数被用来建立物种的摄食策略。使用列联表、对应分析和多元分析（MANOVA）来评估饮食与性别的独立性、干湿季和大小的独立性。通过 Levin 的生态位宽度指数和 Pianka 的饮食重叠指数确定了 D. longa（按性别和大小间隔）的营养关系，并通过零模型确定了它们的显著性。还计算了每个大小间隔和物种的营养水平。Dasyatis longa 表现出狭窄的生态位宽度，主要以虾和鱼类为食，其饮食依赖于大小，但不依赖于性别或季节。幼年个体（I 类）以虾为食，亚成体（II 类）以鱼类为食，成体（III 类）以十足目动物为食。在 I 类和 II 类以及 II 类和 III 类之间发现了显著的重叠。营养水平表明 D. longa 是二级或三级消费者。由于对长尾魟的主要猎物虾的捕捞压力相当大，因此确定它们适应猎物种群变化的能力将非常重要。
