Acrossocheilus paradoxus affects benthic resources and communities in a subtropical stream in Taiwan

Abstract

The effects of benthic fish on stream benthic resources and communities have not been effectively studied in subtropical East Asia. This study examined the effects of the Acrossocheilus paradoxus benthic fish on benthic resources and communities in Jiaolong Creek, Central Taiwan. A cage experiment with a no-fish control and a fish treatment was used to study the effects of A. paradoxus on the mass of algae and detritus and on the density and community structure of algae and macroinvertebrates. Additional diets, nutrient excretion rates, and feeding scars of this fish were also examined. A. paradoxus fed primarily on algae and detritus. The fish treatment had lower chlorophyll a, phaeophytin a, and ash-free dry mass than the no-fish control. Areas of concentrated feeding scars by A. paradoxus had consistently lower chlorophyll a than adjacent non-feeding areas. The mean density of macroinvertebrates was lower in the fish treatment; however, the taxa richness and diversity were higher. Algal and macroinvertebrate communities differed between treatments. A. paradoxus altered the benthic resources and communities in this study.Abbreviations: AFDM, ash-free dry mass; ANOVA, analysis of variance; MRPP, multiple-response permutation procedure; NMDS, non-metric multidimensional scaling.

Are high densities of fishes and shrimp associated with top‐down control of tropical benthic communities? A test in three Hong Kong streams

“…However, the lack of any significant effect of fish removal on periphyton accumulation or silt accrual on cobbles was unexpected, given that periphytic FPOM makes up approximately one‐quarter of the diet of P. myersi (Yang & Dudgeon, ). Small balitorids evidently did not exert the bioturbating effects associated with relatively large‐bodied loricariids, parodontids and prochilodontids in the Neotropics (Flecker, ; Flecker & Taylor, ), nor the Asian cyprinid Acrossocheilus paradoxus that resuspend silt while grazing (Wang, ).…”