Centre for Fish and Fisheries Research, Murdoch University, Murdoch, Western Australia 6150, Australia.
J Fish Biol. 2010 Apr;76(6):1255-76. doi: 10.1111/j.1095-8649.2010.02537.x.
The dietary compositions of three medium to large targeted fish species, which co-occur over reefs in temperate waters of south-western Australia, were determined. These data were then used to ascertain statistically the extent to which body size, season and habitat influence the diets of these species and the degree to which food resources were partitioned among and within those species, and thus reduced the potential of interspecific and intraspecific competition. On the west coast, Bodianus frenchii (Labridae) and Epinephelides armatus (Serranidae) spent their whole life over prominent limestone reefs, as did Glaucosoma hebraicum (Glaucosomatidae) in all but juvenile life, when it lived over low-relief, limestone substrata. The dietary composition of each species changed with increasing body size, which, in G. hebraicum, was particularly pronounced at c. 300 mm total length (L(T)) and therefore at the size when this species shifts habitat. When the three species co-occurred over the same reefs, their dietary compositions were significantly different, with that of B. frenchii being by far the most discrete, reflecting a far greater contribution by sedentary taxa. Thus, the diet of B. frenchii was distinguished from those of the other two species in containing substantial volumes of bivalve and gastropod molluscs and echinoid echinoderms and essentially no teleosts. Although the diets of G. hebraicum and particularly E. armatus were dominated by teleosts, and especially for larger individuals, the former species ingested greater volumes of cephalopods and small crustaceans. The pointed jaws of B. frenchii, with their forwardly directed and interlocking anterior incisors, are ideally adapted for biting and retaining their invertebrate prey, which are attached to or reside within reef crevices. In contrast, the mouths of G. hebraicum and E. armatus are broader and rounder and contain numerous small, slender and inward-pointing teeth. These teeth, in conjunction with prominent backward-curved canines in E. armatus, facilitate the capture and retention of fish prey. Observations in situ indicate that G. hebraicum is a suction feeder, while E. armatus is predominantly a ram feeder. Although reef environments on the west and south coasts differ, the diet of B. frenchii on these coasts differed only slightly. Interspecific differences in diet, combined with size-related changes in dietary compositions and the occupation of different habitats by juvenile and adult G. hebraicum, reduce the potential for competition for food resources among and within B. frenchii, G. hebraicum and E. armatus and thus helps facilitate the coexistence of these species which historically have been abundant over reefs in south-western Australia.
测定了三种中大型目标鱼类的饮食组成，这些鱼类在澳大利亚西南部温暖水域的珊瑚礁中共存。然后，利用这些数据统计确定了体型、季节和栖息地在多大程度上影响这些物种的饮食，以及食物资源在这些物种之间和内部的分配程度，从而减少了种间和种内竞争的可能性。在西海岸，Bodianus frenchii（Labridae）和 Epinephelides armatus（Serranidae）一生都在突出的石灰岩礁上度过，而 Glaucosoma hebraicum（Glaucosomatidae）除了幼年生活在低浮雕石灰岩基质上外，一生都在那里度过。每个物种的饮食组成随着体型的增加而变化，在 G. hebraicum 中，这种变化在大约 300 毫米总长度（L(T)）时特别明显，此时该物种会改变栖息地。当这三种物种在同一珊瑚礁上共存时，它们的饮食组成有显著差异，其中 B. frenchii 的饮食组成最为离散，这反映了更静止的分类群的更大贡献。因此，B. frenchii 的饮食与其他两种物种的饮食明显不同，它含有大量双壳类和腹足类软体动物和海胆棘皮动物，基本上没有硬骨鱼。尽管 G. hebraicum 和特别是 E. armatus 的饮食主要由硬骨鱼组成，特别是对于较大的个体，前者摄入更多的头足类动物和小型甲壳类动物。B. frenchii 的尖嘴，其向前指向并互锁的前齿，非常适合咬住并保留它们附着在或居住在珊瑚礁裂缝中的无脊椎动物猎物。相比之下，G. hebraicum 和 E. armatus 的嘴更宽更圆，并且含有许多细小、细长且向内指向的牙齿。这些牙齿与 E. armatus 向后弯曲的犬齿一起，有助于捕获和保留鱼类猎物。现场观察表明，G. hebraicum 是一种抽吸式摄食者，而 E. armatus 则主要是一种冲击式摄食者。尽管西海岸和南海岸的珊瑚礁环境不同，但这两个海岸的 B. frenchii 饮食差异很小。种间饮食差异，加上与体型相关的饮食组成变化，以及幼年和成年 G. hebraicum 占据不同的栖息地，减少了 B. frenchii、G. hebraicum 和 E. armatus 之间和内部争夺食物资源的潜力，从而有助于促进这些物种在澳大利亚西南部的珊瑚礁中大量共存。
