• Korean Journal of Ichthyology
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• v.25 no.2
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• pp.135-140
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• 2013

Microphysogobio koreensis, an endemic Korean freshwater fishes belonging to Cyprinidae, is protected as a 2nd grade of endangered fishes by the ministry of the Environment. For this species, the study on the spawning microhabitat including structure of streambed and spawning grounds was carried out. The streambed that this species mainly lives consists of boulders, cobbles, and pebbles, the so-called Bb type, with a depth of 0.3 to 1.0 m and a rapid velocity of $0.5{\pm}0.2$ m/sec. But the main spawning grounds where the spawning is actually occurring, is relatively shallower, $0.4{\pm}0.1$ (0.4~0.6) m depth, and faster, $0.8{\pm}0.1$ (0.6~0.9) m/sec velocity, whereas the region that the fertilized eggs are attached are rather slowest to 0.4m/sec. The spawning starts at a water temperature of $20^{\circ}C$ in earlier May, laying their eggs on the cobbles' or boulders' surface or in between them. In particular, with a wide range of streambed structures, natural spawning grounds' environments may let the fertilized eggs not be swept from rapid current and secure efficient dissolved oxygen. The individuals, however, do not appear at the grounds any more after the spawning season, and it is expected that they may move into deeper water such as Lakes or lower streams.

• Korean Journal of Ichthyology
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• v.23 no.3
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• pp.234-241
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• 2011

Habitat, reproduction and feeding habit of endangered fish Koreocobitis naktongensis from Jaho stream, Gyeongsangbuk-do, Korea were investigated from March 2010 to June 2011. This species inhabits at the upper and middle parts of stream, which were composed of cobbles and pebbles bottom. The current velocities in these microhabitat were 5~10 cm/sec and depth were 50~110cm. The sex ratio of female to male was 1 : 0.92. It is presumed that the spawning season is from May to June when water temperatures were 17 ~ 20$^{\circ}C$. The average number of mature eggs in ovary were about 22,643 (15,909~30,323), mean egg diameter was 0.87${\pm}$0.05mm. K. naktongensis fed mainly on Chironomidae (IRI, 72.0%) and Ephydridae (26.9%) of Diptera.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.352-360
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• 2005

Acheilognathus signifer is distributed widely in high density in the Naechon-stream. The order of this-stream was 2 ${\sim}$ 4 and the water width is wide but the depth is relatively shallow and the sinuosity is 1.83, which indicates a meandering stream. The water width/stream width ratio is 1.59, which suggests moderate entrenchment. Naechon-stream was classed as B type by Rosgen (1995). The natural habitat of A. signifer is a slow flow velocity pool, like a backwater pool, which is made up of piled up boulders that restricts the flow of water. The stream bed is made up of boulders and sands that enable the spawning host to inhabit. A. signifer selects a microhabitat where the boulders furnish hiding places. The Habitat of A. signifer is strongly affected by the existence or not there of U. douglasiae sinuolatus. After hatching from the mussel, A. signifer inhabits the surface of the water. It then moves to the low layer once it acquires swimming ability. While A. signifer inhabits the river in summer, A. signifer moves to the deeper layers in winter, where there are the refuge like rocks and boulders. In spring A. signifer moves from the deep water to the river line where the mussels reside.