The impact of nigorobuna crucian carp larvae/fry stocking and rice-straw application on the community structure of aquatic organisms in Japanese rice fields

Abstract

We examined the effects of predation by Nigorobuna Carassius auratus grandoculis larvae and fry, a crucian carp endemic to Lake Biwa, Japan, on the community structure of aquatic organisms in rice fields. Six experimental plots with three different rice-straw treatments in the presence/absence of stocked larvae were prepared. In each plot, the number of aquatic organisms ranging in size from 30 lm to 5 mm in the water, as well as those from 63 lm to 5 mm in size in the surface sediments, was surveyed 6, 13, 20, 26, 34, and 41 days after the onset of irrigation. Three-day-old fish larvae were released on day 10. Undigested organisms in the gut contents of the larvae or fry were identified on days 20, 26, 34, and 41, respectively. Ten-day-old larvae mainly preyed on Cladocera, but the fry thereafter shifted to Diptera as their main prey. While Cladocera and Podocopida decreased in fishstocked plots, Euglenales and Halteriida became more abundant there. Top-down or bottom-up effects of fish seemed to control these changes in community structure.

Impact of Feeding Schedule on the Growth Performances of Tilapia, Common Carp, and Rice Yield in an Integrated Rice-Fish Farming System

“…Number of effective tillers per hill (effective tillers hill −1 ) To calculate the effective tillers per hill, only the ear-bearing tillers were calculated from every sample, and the average of samples was taken [25].…”

Body size and temperature dependence of routine metabolic rate and critical oxygen concentration in larvae and juveniles of the round crucian carp Carassius auratus grandoculis Temminck & Schlegel 1846

“…This species is an ingredient in a traditional food called Funazushi, a fermented fish that is a taste of home for locals, making this species a highly valuable fisheries target (Yamazaki et al, 2010). This species is an ingredient in a traditional food called Funazushi, a fermented fish that is a taste of home for locals, making this species a highly valuable fisheries target (Yamazaki et al, 2010).…”

“…In the present study, body weight (W) and temperature dependence of routine metabolic rate (RMR) and hypoxia tolerance, as indicated by critical oxygen concentration (Pc), were determined in round crucian carp, Carassius auratus grandoculis Temminck & Schlegel 1846. This species is an ingredient in a traditional food called Funazushi, a fermented fish that is a taste of home for locals, making this species a highly valuable fisheries target (Yamazaki et al, 2010). Round crucian carp is an endemic subspecies belonging to the family Cyprinidae (Yuma et al, 1998), and inhabits the macrophyte zone during its larval and juvenile stages (Miura, 1966).…”

Recent microscale disturbance of gene flow in threatened fluvial lamprey, Lethenteron sp. N, living in a paddy water system

“…'Old-style' paddy fields in the central area of the Japanese Archipelago, with their shallow irrigation canals and earth ditches, have proven beneficial to the conservation of insects, fishes, frogs, and birds (e.g., Lane and Fujioka 1997;Yamazaki et al 2010). However, recent excessive consolidation of paddy fields (e.g., with channelization by concrete walls and construction of sluice gates) may negatively affect the inhabitants of these areas.…”