Mengyejiang River, Red River basin
The Mengyejiang River is geographically located adjacent to neighbouring Laos. The distance counting around 15 km. In fact it is the southwesternmost branch of the Red River basin in China. The Mengyejiang affluents to the Babianjiang River, which in turn flows into the Black River (or Chinese Lixianjiang River 李仙江).
People living in this valley mainly belong to the Hani minority; well known for the Hani Rice Terraces of Yuanyang County. Hani people are actually more into agriculture (sugar cane and, of course, rice are the major crops) than fishing. But along the shores of the Mengyejiang River fishing gains more popularity.
There are plenty of fishtraps along the Mengyejiang River. The traps are made of bamboo straps braided to form a net. The mouth of the traps is funnel shaped to guarantee the most possible coverage. The posteriormost end of the conical bamboo tube can be removed to take out trapped fish.
Usually a trap is placed in the middle of a riffle section; to its left and right there are fences guiding fish in the mouth section. In some cases I saw traps in stream bottle necks, where water is forced through very narrow openings.
This is another kind of fishtrap used for larger fishes, such as Hemibagrus catfishes. Usually these traps are placed in shallow, sluggish sections of the water body. Backwaters make an ideal place. The traps on the photographs just stand in 30 cm deep water. Large individuals of catfishes ususally roam these shallow areas scavenging during night and get trapped. These traps are operated by a cable pull principle.
Mist! - The photograph on the left was taken at around 06:15 in the morning. We have been invited by local Hani people to empty their fish traps early in the morning. Hence, we got up at 05:00, drove down the mist-laden hills from Jiangcheng town, where we had our accomodation. The mist was so dense that the ride almost ended fatally.
We picked up the trap owner, a Hani lady. I asked her if we need to take our ‘water’ shoes. She denied, but after a 1 km walk through dense shrubs, man-high grasses, ferns & underwood we finally reached a small tributary of the Mengyejiang River and she (almost expectedly) asked us to take off our shoes to walk through the stream to the trap. The water felt like ice; barefoot through the stream was just like a good foot massage.
The night’s yield was not spectacular; just a handful of very common cyprinids.
Syntopic we found Vanmanenia tetraloba (Mai, 1978) occuring in the riffle section of the Mengyejiang River. Detailed information are linked here.
The nemacheilid loach Schistura callichromus was rather common at EW-CN 66-09; we caugth plenty. Detailed information about this species you can find in the species section linked here.
Vanmanenia tetraloba in the container viewed from above immediately after capture.
In this remote area of China one can find a considerably high number of undescribed goby species; such as this one. I refer to it as Rhinogobius sp. G3; photograph shows a nuptial male.
Female of Rhinogobius sp. G3.
Among all the specimens of nemacheilids we caught there were three specimens of a not yet described Physoschistura. I refer to it as Physoschistura sp. N3. The original description is ongoing.
In total we just got three different nemacheilid species in the Mengyejiang River. This is a quite low number; in his monograpgh about Indochinese loaches Kottelat reports up to six different nemacheilid loaches syntopicly occuring (Kottelat, 1990).
So far, we couldn’t identify this Macrobrachium shrimp from Mengyejiang River. Since we fished in the riffles there were just few of this shrimps.
The balitorad flat loach Sinogastromyzon tonkinensis Pellegrin & Chevey, 1935 was rather common in the riffle section; in fact, the predominant balitorid species. It closely resembles S. rugocauda Mai, 1978 in color pattern and overall appearance. Differences are spinous anal ray strong in S. tonkinensis vs weak, and 50 lateral line scales vs 38-44. Species fact sheet here.
Beaufortia daon (Mai, 1978) was described from the Vietnamese part of the Black River subbasin. It can be rather easily distinguished from Beaufortia leveretti by the absence of a notched mandibular, anus not covered by the pelvics and by 75-85 lateral line scales vs 60-70 in B. leveretti. Kottelat twice errorneously placed this species in the genus Pseudogastromyzon basing on ‘notched pelvics’ as described by Mai in its original description (Kottelat 2001a; 2001b; in his monograph about northern Vietnamese Freshwater Fishes he additionally cited a wrong publication date of Mai’s original description, viz 1998; correct year is 1978). In fact, almost all Beaufortia have fused pelvics with a slightly notched distal section.
Beaufortia daon was not very common in the Mengyejiang River riffles. This species’ fact sheet is linked here.
This garfish or needlefish of the family Belonidae is Xenentodon canciloides (Bleeker, 1853). Kottelat displays a much better picture than mine of a beautifully preserved specimen (Kottelat, 2001a). He does not mentioned its occurence in China, but in the Mekong basin in Laos, Thailand, Cambodia and Vietnam and in Sundaland. Unfortunately he does not provide an identification key since he reports X. canciloides as the only species of the family Belonidae in Loatian waters.
Roberts then provided a usuable key for identication of Xenentodon species occuring in Western Borneo. Aside X. cancila and X. canciloides he lists at least one more undescribed species. He is not sure if it is one or more species. Therein X. canciloides is described as a species with slender and comparatively delicate jaws, length of the upper jaw/SL 2.3-2.6, enlarged teeth in upper jaw 21-32, dorsal fin origin slightly posterior to anal fin origin, a slender and smaller species, usually not exceeding 300 mm SL (Roberts, 1989).
Chinese literature list this species as Tylosurus strongylurus (van Hasselt, 1823) over decades (e.g. Chu & Chen, 1990); these days placed in the genus Strongylura. Tylosurus resp. Strongylura is a genus of marine and estuarine species, which do not occur so far inland. Xenentodon can be distinguished from the other two genera by dorsal and anal fins nearly oppositely placed (vs dorsal fin clearly inserted behind anal) and one pair of upper pharyngeal teeth (vs two or three pairs) (Talwar & Jhingran, 1992).
The displayed specimen is 143 mm long (SL).
Watch the size! The largest specimen of Schistura callichromus; a female featuring yellow finnage and extrordinarily bulging lips. Catalogued as EPC0520; 87.8 mm SL; 105.5 mm TL.
