The production and trophic ecology of shallow-water fish assemblages in southern Australia .2. Diets of fishes and trophic relationships between fishes and benthos at Western Port, Victoria
The production and trophic ecology of shallow-water fish assemblages in southern Australia .2. Diets of fishes and trophic relationships between fishes and benthos at Western Port, Victoria
复制标题
DOI：
10.1016/0022-0981(95)00084-4
复制
发表时间：
1995-12-13
影响因子：
2
通讯作者：
Shaw, C
中科院分区：
文献类型：
--
作者：
Edgar, GJ;Shaw, C
1989年8月至1990年11月，在西港的海草和无植被生境中共采集了91种5113条鱼类进行膳食分析，其中720条动物有空肠。没有一个常见的物种被发现有一个高度专业化的饮食。甲壳类动物的饮食中的大多数（69%）的88个物种与非空的肠道，与五个物种（girellid，mugilid，monacanthid和两个虎鱼）消耗大量的藻类材料，只有一个物种[的garfish Hyporhamphus melanochir（Valenciennes）] ingerglass海草在任何数量。一般来说，一个物种的青少年和成年人之间的饮食差异是一样大的饮食差异属于不同物种的鱼时，在相同的身体大小。在甲壳类饲养者中，饮食通常从主要的桡足类变为主要的Peracarids（端足类，等足类和糠虾），湿体重约为0.1克，从主要的Peracarids变为主要的螃蟹和虾，湿体重约为100克。在所研究的物种范围内，摄食猎物的大小和鱼类生物量之间存在密切关系。猎物长度平均为捕食者长度的7.5%。刺网渔获物中的优势种是乌鱼Aldrichetta forsteri（Cuvier & Valenciennes），它的食性不寻常，因为它的猎物比相同体型的其他鱼类要小，而且还消耗大量的藻类物质。小型鱼类的主要捕食者是当地居民的物种，岩石平头Platycephalus laevigatus居维叶和Valenciennes在海草床和沙平头Platycephalus laevigatus居维叶和Valenciennes在无植被的网站。甲壳类动物提供了所有地点的小鱼群落的大部分饮食摄入量，软体动物和多毛类动物也很重要，但仅在两个地点提供了超过25%的食物消费。如果将每日消费率与每日产量或食物进行比较，经计算，大于1毫米筛目的甲壳类动物的产量全部被鱼类消费。非甲壳类底栖生物的生产量比鱼类捕食者的消费量高一个数量级。这些结果表明，高品质的甲壳类猎物的可用性可能会限制生产的鱼类？鱼类很可能会扩散性地争夺甲壳类动物的猎物。这一假设得到以下观察结果的进一步支持：在秋季，当甲壳类生产无法支持鱼类总消费量时，与海草有关的鱼类的状况下降，死亡率很高。
A total of 5113 fishes belonging to 91 species was collected from seagrass and unvegetated habitats at Western Port for dietary analysis between August 1989 and November 1990, with 720 animals having empty guts. None of the common species was found to have a highly specialised diet. Crustaceans were the dominant component in the diets of the majority (69%) of the 88 species with non-empty guts, with five species (a girellid, a mugilid, a monacanthid and two gobiids) consuming large amounts of algal material, and only one species [the garfish Hyporhamphus melanochir (Valenciennes)] ingesting seagrass in any quantity. In general, dietary differences between juveniles and adults of a species were as great as dietary differences between fish belonging to different species when at the same body size. Amongst the crustacean feeders, diets generally changed from predominantly copepods to predominantly peracarids (amphipods, isopods and mysids) at approximate to 0.1 g wet body weight, and from predominantly peracarids to predominantly crabs and shrimps at approximate to 100 g. Across the range of species examined, there was a close relationship between the size of ingested prey and fish biomass. Prey length averaged 7.5% of predator length. The dominant species in gillnet catches, the mullet Aldrichetta forsteri (Cuvier & Valenciennes), possessed an unusual diet because prey were smaller than for other fishes of the same body size and large quantities of algal material were also consumed.Similar trophic pathways leading to fishes were found in different habitats, with the major linkages being from benthic microalgae and detritus through epifaunal crustaceans to the smaller fishes. The major predators of small fishes were locally-resident species, the rock flathead Platycephalus laevigatus Cuvier & Valenciennes in seagrass beds and the sand flathead Platycephalus bassensis Cuvier & Valenciennes at unvegetated sites. Crustaceans supplied most of the dietary intake for the small fish communities at all sites, with molluscs and polychaetes also important but supplying >25% of food consumed at only two sites. When daily rates of consumption were compared with daily production or food, the production of crustaceans >1 mm sieve size was calculated to be all consumed by fish. The production of the non-crustacean benthos was an order of magnitude higher than that consumed by fish predators. These results indicate that the availability of high quality crustacean prey may limit the production of fishes? and that fishes are likely to compete diffusively for crustacean prey. Additional support for this hypothesis is provided by the observations that the condition of seagrass-associated fish declined, and mortality rates were high, during the autumn season when total fish consumption could not be supported by crustacean production.