Identification:
- Morphological Characteristics: Medium-sized fish. Head length is 2.86–3.62 times the eye diameter, and 2.26–2.93 times the interorbital distance. The body is deep, with a very high, angular profile anterior to the dorsal fin. The body is laterally compressed, with a thinner dorsal profile compared to the ventral profile. The mouth is inferior or subterminal, and the gape extends to the level of the mid-point of the nostril and the anterior eye margin. The eyes are of moderate size. The interorbital space is broad and slightly convex. There are two pairs of barbels, which are nearly equal in length and longer than the eye diameter. The dorsal fin originates anterior to the pelvic fin origin, closer to the snout than to the caudal peduncle. The anus is located near the base of the anal fin. The last unbranched rays of the dorsal and anal fins are ossified and serrated posteriorly. The caudal fin is deeply forked. Scales are cycloid and thin. The lateral line is complete, running along the midline of the body. The dorsal surface is gray, while the ventral surface is pale or off-white. There are 13 dark stripes along the body, extending from behind the operculum along the scale margins to the caudal fin base, interspersed with distinctive pale markings. Fins are pale gray.
Biology and Ecology:
- Habitat and Diet: This fish inhabits fast-flowing rivers and streams, primarily in the benthic zone. It feeds on benthic invertebrates, other invertebrates, and organic detritus.
- Size and Reproduction: The average size of caught fish ranges from 0.4–1 kg, with a maximum size of up to 3 kg. The spawning season is from April to June. Eggs are adhesive, attaching to submerged substrates. Spawning grounds are typically located in areas along rivers and streams with aquatic vegetation and algae. Other aspects of this fish’s biology are not well-studied.
Distribution:
- National: Rivers and streams within the Da River system in Son La (Ta Khoa, Yen Chau) and Hoa Binh (Van Yen, Suoi Rut, Da Bac) provinces.
- Global: Endemic to Vietnam.
Value:
- Significance: This is a Vietnamese endemic species and a rare fish in the Da River. The fish has palatable flesh, is favored by local people, but has low production and limited distribution, resulting in constrained economic value.
Conservation Status:
- Threats and Current Status: Habitat degradation has altered the fish’s habitat, with the historical distribution being encompassed within the Hoa Binh reservoir. The species has not been observed since 1990 and may be extinct or have migrated to smaller streams near the reservoir, but in very small numbers. The species is considered rare and in need of protection.
IUCN Red List Status:
- EN A1c,b B1+2b,c.
Conservation Measures:
- Current Measures: It was included in the list of fish species requiring protection by the Fisheries sector in 1996. However, there are currently no specific regulations to protect this species.
- Recommended Actions: Further research is needed in historical distribution areas to determine the current status of the species. Conservation efforts should focus on collecting wild fish for captive breeding, propagation, and reintroduction in suitable habitats. Furthermore, research is recommended to safeguard the species’ genetic material and hybridization with other species of the Cyprinus genus to enhance the economic value of this fish.