Relationships between ayu Plecoglossus altivelis altivelis and other organisms in stream communities
2006
Katano, O.(National Research Inst. of Fisheries Science, Ueda, Nagano (Japan). Freshwater Fisheries Lab.) | Abe, S. | Nakamura, T.
Although ayu Plecoglossus altivelis altivelis did not change the abundance of inorganic nutrients such as phosphorus and nitrogen, ayu decreased the abundance of diatoms and increased the abundance of blue-green algae such as Homoeothrix. The intensive scraping of ayu also reduced the number of chironomid and tipulid larvae that mainly inhabit the upper surface of cobbles and boulders, and increased the percentage of ephemeropteran nymphs such as Ephemeroptera. Ayu had a negative effect on other omnivorous fishes such as Japanese dace Tribolodon hakonensis and pale chub Zacco platypus. In contrast, the presence of Japanese dace, pale chub and pike gudgeon Pseudogobio esocinus esocinus enhanced ayu growth by decreasing the number of algivorous invertebrates and increasing the algal biomass through trophic cascades. Interspecific relationships in stream ecosystems are thought to be very important for the management of biodiversity and ayu growth.
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