Comparative ecology of the African pike, Hepsetus odoe, and tigerfish, Hydrocynus forskahlii, in the Zambezi River floodplain
Comparative ecology of the African pike, Hepsetus odoe, and tigerfish, Hydrocynus forskahlii, in the Zambezi River floodplain
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赞比西河洪泛区非洲梭子鱼 (Hepsetus odoe) 和虎鱼 (Hydrocynus forskahlii) 的比较生态学
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
L. Kelso
中科院分区：
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作者：
K. Winemiller;L. Kelso
在赞比西河上游的高水位（5 - 8月）和低水位（9 - 12月）条件下，比较了同域分布的非洲狗鱼（Hepsetus odoe）和虎鱼（Hydrocynus forskahlii）的生态。赞比亚排水这两个物种在河流的中部和南部地区以及相关的洪泛平原都很常见，而Hydrocynus在北方地区的快速流动的支流中很常见，而Hepsetus则很罕见。赫普塞特栖息在河流回水、泻湖和缓慢支流的植被环境中，而Hydrocynus几乎完全占据了主要河道的开放水域。在每年的洪水期间，这两个物种的少年共存于被洪水淹没的稀树草原地区。成年Hydrocynus和Hepsetus的大小分布变化相对较小的高，低水条件。胃内容物分析表明，成人大小类的两个物种几乎完全是食鱼的，都显示饮食变化的大小。仅观察到非常小的季节性饮食变化。赫普塞特的饮食约有50%由单铬慈鲷鱼组成，但也包括大量的罗非鱼慈鲷和长颌鱼，Hydrocynus主要消耗慈鲷鱼，但也消耗大量的赫普塞特和小characid鱼。小型类的赫普塞特大量喂养小马乔基鲶鱼（Synadontis spp.）后来转向以慈鲷和食蚁兽为食，而小Hydrocynus则大量捕食Barbus spp。（鲤科），小的characids，和mormyrids。水牛鱼的猎物长度与捕食者长度之比平均约为0·26，赫普塞特鱼的猎物长度与捕食者长度之比平均约为0·40。食物资源竞争的巨大潜力似乎没有实现，由于一个非常高的程度的栖息地分区之间较大的大小类的两个物种。在河流回水和通道栖息地之间的界面，Hydrocynus是一个重要的捕食者Hepsetus，一个因素，应进一步限制后者在主通道的开放区域的发生。
The ecology of sympatric African pike, Hepsetus odoe (Hepsetidae), and tiger fish, Hydrocynus forskahlii (Characidae), were compared during high (May-August) and falling water (September-December) conditions in the Upper Zambezi R. drainage of Zambia. Both species were common in the central and southern regions of the river and associated floodplain, and Hydrocynus was common in the northern region in swift flowing tributaries where Hepsetus was rare. Hepsetus inhabited vegetated environments of river backwaters, lagoons, and sluggish tributaries, whereas Hydrocynus occupied the open water of the main river channel almost exclusively. During the period of annual flooding, juveniles of both species coexist in flooded savanna regions. Size distributions of adult Hydrocynus and Hepsetus changed relatively little between high and low water conditions. Stomach contents analysis indicated that adult size classes of both species are almost entirely piscivorous, and both show diet shifts with changes in size. Only very small seasonal diet shifts were noted. Approximately 50% of the diet of Hepsetus consisted of haplochromine cichlid fishes, but also included large numbers of tilapine cichlids and mormyrids, Hydrocynus consumed primarily cichlid fishes, but also consumed large percentages of Hepsetus and small characid fishes. Small size classes of Hepsetus fed heavily on small machokid catfishes (Synadontis spp.) and later shifted to a diet of cichlids and mormyrids, and small Hydrocynus preyed heavily on Barbus spp. (Cyprinidae), small characids, and mormyrids. Ratios of prey length-predator length averaged approximately 0·26 for Hydrocynus and nearly 0·40 for Hepsetus. The large potential for food resource competition appears not to be realized due to a very high degree of habitat partitioning between larger size classes of the two species. At the interface between river backwaters and channel habitats, Hydrocynus is a significant predator of Hepsetus, a factor that should further restrict the occurrence of the latter in open areas of the main channel.