Identification:
Large fish, tall body, somewhat thick, laterally compressed. The anterior part of the dorsal fin is slightly elevated.
Head is small, nape is notably lower than the back. Snout is slightly blunt. Two pairs of barbels are quite developed; the maxillary barbels are larger than the rostral barbels and longer, exceeding the diameter of the eye. Eyes are moderately sized and positioned slightly above. The interorbital space is wide and somewhat flat. The mouth is at the snout’s tip or slightly below, horseshoe-shaped, and the gape does not reach the anterior margin of the eye. Upper and lower lips are thick, with numerous small fleshy papillae.
The dorsal fin originates behind the pelvic fin, positioned between the snout’s tip and the caudal fin’s base. The anus is adjacent to the anal fin base. The last unbranched rays of the dorsal and anal fins are ossified and robust, with serrations on the posterior side. The caudal fin is deeply forked. Scales are large, round, and thick. The lateral line is complete. The back and flanks are grayish-black, the belly is creamy white.
Distinctively, there are 12-13 black stripes running along the body between the scale rows. The fins are orange, with the tips being grayer in the middle.
Biology and Ecology:
The fish inhabit the bottom and mid-water layers of rivers and streams in the Đà River system, where the current is relatively strong and the substrate is composed of many pebbles and rocks. This fish is omnivorous, and its diet usually consists of insect larvae, mosquito larvae, oligochaete worms, mollusks, organic debris, and food particles.
The fish can reach a large size, up to 10 kg. Commonly, fish are found at 5-6 kg, with an average harvest size of 1-2 kg.
Spawning season is from April to June. Spawning grounds are located in the mid and upper reaches where the water current is swift, with many rocks, pebbles, and aquatic plants, and algae attached to the bottom. Eggs are adhesive and adhere to leaves and other substrates in the water.
Distribution:
- Within Vietnam: Rivers and streams of the Đà River system in the provinces of Lai Châu, Sơn La, and Hòa Bình.
- Globally: Endemic to Vietnam.
Value:
This fish is an endemic species within an endemic genus in Vietnam. The fish is relatively large, has delicious meat, and is an economically important species in the Northwest mountainous region. The fish has a very small head and a short, high body. It can be hybridized with carp to increase the meat ratio of the hybrid fish.
Status:
In the 1960s, this fish was abundant in the Đà River, especially in the Lai Châu province. However, over the past 20 years, the population of this fish has significantly decreased due to overfishing, deforestation at the headwaters (leading to more floods which disturb the riverbed), and, notably, the construction of the Hòa Bình Reservoir, which has reduced its habitat. Despite many years of surveying, the fish is no longer found in its former distribution areas, and it may have become extinct. In the coming years, the government will build the Sơn La reservoir, and the flooded area will extend to Lai Châu, which will surely affect the distribution and survival of the fish.
Classification:
EN A1a,c,d B1+2a,b,c.
Conservation Measures:
The species was included in the list of protected species by the fisheries sector in 1996. However, necessary regulations to protect this fish have not been implemented. It is essential to ban the fishing of this fish in natural waters in Lai Châu province for 8-10 years. Further research on this species is needed to establish conservation measures and promote sustainable utilization. The fish should be bred in captivity, and research on breeding programs should be undertaken to preserve the valuable gene pool of this species and contribute to the recovery of fish populations in natural waters.