Influence of altered freshwater flow regimes on abundance of larval and juvenile Gilchristella aestuaria (Pisces:Clupeidae) in the upper reaches of two South African estuaries
Influence of altered freshwater flow regimes on abundance of larval and juvenile Gilchristella aestuaria (Pisces:Clupeidae) in the upper reaches of two South African estuaries
复制标题
淡水流量变化对两个南非河口上游 Gilchristella aestuaria（双鱼座：Clupeidae）幼虫和幼鱼丰度的影响
DOI：
10.1071/mf01077
复制
发表时间：
2002
影响因子：
1.8
通讯作者：
A. Paterson
中科院分区：
文献类型：
--
作者：
N. Strydom;A. Whitfield;A. Paterson
过去对受淡水流动制度变化影响的南非河口的调查集中于河流流量减少对依赖河口生活的海洋鱼类物种的影响。这项研究比较了河口居民Gilchristella aestuaria的幼体和幼体丰度。Gilchristella aestuaria位于‘淡水匮乏’的Kariega河口和‘富含淡水’的大鱼口的上游。Kariega河口的渔获量明显高于大鱼口。各系统的仔稚鱼密度与盐度、温度、浊度和河流流量之间存在相关性和回归关系。根据这些系统中不同的渔获量，河流流量被发现是最可能的决定因素。由于从流域间调水计划获得的过多的河流流量，大鱼系统似乎将Aestuaria幼体和幼体冲走。尽管对河口系统的淡水输入对南非河口下游的育苗功能至关重要，但过量的淡水供应会改变上游河口栖息鱼类的幼体组成。
Past investigations into South African estuaries that are subject to altered freshwater flow regimes have concentrated on the effects of reduced river flow on recruiting estuary-dependent marine fish species. This study compares larval and juvenile abundance of an estuary resident, Gilchristella aestuaria, in the upper reaches of the ‘freshwater-deprived’ Kariega Estuary and the ‘freshwater-rich’ Great Fish Estuary. Catches in the Kariega Estuary were significantly greater than those in the Great Fish Estuary. Larval and juvenile densities were correlated and regressed with salinity, temperature, turbidity and river flow in each system. River flow was found to be the most probable defining factor in terms of the contrasting catches in these systems. G. aestuaria larvae and juveniles appear to be flushed out of the Great Fish system as a result of the excessive amount of river flow received from an inter-basin water transfer scheme. Although freshwater input into estuarine systems is vital for the nursery function of the lower reaches of South African estuaries, excessive supply can alter the larval composition of estuary-resident fish species in the upper reaches.