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Pseudobagrus medianalis

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA ACTINOPTERYGII SILURIFORMES BAGRIDAE

Scientific Name: Pseudobagrus medianalis
Species Authority: (Regan, 1904)
Common Name(s):
English Dianchi Bullhead
Synonym(s):
Macrones medianali (Regan, 1904)
Pseudobagrus medianalis Burgess, 1989
Taxonomic Notes: Originally Macrones medianalis, but changed in 1989 to Pseudobagrus medianalis by Burgess.

Assessment Information [top]

Red List Category & Criteria: Critically Endangered B2ab(iii) ver 3.1
Year Published: 2008
Date Assessed: 2008-01-01
Assessor(s): Chen, X.-Y.
Reviewer(s): Kullander, F. (Freshwater Fish Red List Authority) & Smith, K. (IUCN Freshwater Biodiversity Assessment Unit)
Justification:
Pseudobagrus meridionalis is endemic to Lake Dianchi basin, Yunnan Province, China. This species was a very common fish in Lake Dianchi prior to the mid-20th century. The population started to decline throughout the basin from 1950–60’s. It became rare in the 1970’s (He et al. 1983), and it is now extinct in the lake itself and only known from two springs and the effluent river Zhangjiu. These are only three subpopulations known and they are severely fragmented by the polluted lake body. The major threats to the species are pollution, habitat loss, over-fishing and introduced species. The total area of occupancy of the three locations is less than 10 km².
History:
1996 Endangered
1994 Indeterminate (Groombridge 1994)

Geographic Range [top]

Range Description: This species is endemic to the Dianchi basin and its effluent, Zhangjiu River. Historically, it occurred through out Lake Dianchi basin including in the lake body (where it had once been very common fish in Lake Dianchi prior to the mid-20th century), streams and headwater springs. But since the 1970’s it has become absent from the lake, and now is only known to occur in two springs (White Dragon Spring (24°52"36.7'N, 102°51"47.7'E, 1,921 m above sea level) and Longwangtan Spring (24°32"31.5'N, 102°40"22.4'E, 1,932 m above sea level)) and an effluent river (Zhangjiu River) on east bank of the lake. However the springs may be connected by small underground karst rivers. The species may also occur in some other rivers and resevoirs around the lake that have not yet been investigated.
Countries:
Native:
China (Yunnan)
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: No information.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: At present, the relic populations of P. medianalis mainly exists in spring pools and the stream from the spring to the lake. The water of one of the springs is approximately 3 m in maximum depth, clear to the bottom, warm and stable, 22.2-22.8°C (annual average 22.4 ± 0.2°C), pH 7.58-7.81 (annual average 7.72 ± 0.08) 6.5 and there is good macrophytes beds in dominance of Hydrilla verticillata and curly leaf pondweed, Potamogeton crispus. Two other species of endemic fish, a Cyprinidae fish, Sinocyclocheilus grahami and a Balitoridae fish, Yunnanilus discoloris, and at least three species of introduced cyprinid fish, Common carp, Cyprinus carpio, Crucian carp, Carrasius auratus auratus and Grass carp, Ctenopharyngodon idella occur sympatrically with P. medianalis in this spring. It is a cryptic benthic fish and prefers to hide under rocks and macrophytes beds at day time, and moves around at night and feeds on small fishes and aquatic invertebrates, such as insects, worms and molluscs.
Systems: Freshwater

Threats [top]

Major Threat(s): Habitat loss is the critical threat to P. medianalis, including the pollution of water and soil which decreased aquatic macrophytes, and the utilization of springs as fishery ponds. Since 1958, the fries of ‘‘the four cultured carps’’, Black carp, Mylopharyngodon piceus, Grass carp, Silver carp, Hypophthalmichthys molitrix and Big head carp, Hypophthalmichthys nobilis have been introduced into the lake (He et al. 1983, Gao et al. 1990) and over-released grass carp by local fishery department heavily grazed macrophytes in the lake. Overfishing is a threat to those individuals living in springs and streams; competition and predation from the introduced fishes may become a threat as well.

Conservation Actions [top]

Conservation Actions: This species is already being suggested as a provincial key protected animal in 2003. Beginning in 2003, a GEF/The World Bank funded project was established in Kunming, Yunnan to conserve and try to restore the aquatic biodiversity of Lake Dianchi. A thrice-yearly survey and monitoring of the aquatic biodiversity, including P. medianalis has been implemented since spring of 2004. An ex-situ conservation effort of a small flock will be conducted soon. Some individuals will be moved into fish ponds of a breeding center and cultured. When hatchlings grow up to certain size being suitable for surviving in wild, some juveniles will be released back to their original habitats. By public awareness works of the project since the pilot project in 1999, local people already understood the rarity of P. medianalis and its major habitat, and the springs have been finely protected. Several springs were recommended to be local reserve areas by the assessor to the local government.

Citation: Chen, X.-Y. 2008. Pseudobagrus medianalis. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 02 October 2014.
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