Aquatic biotopes along the Red River and Mekong with special reference to the ichthyofauna - December 2009/January 2010
Yunnan 2009 - Red River, Mekong
The photograph on the left shows the Red River main channel during the peak of the dry season in end of December, a couple of kilometers downstream of Yuanyang town.
As you can see there are extended sections of dried up river bed. The time during the drought is used by the Chinese for dredging gravel. Gravel is in enormous demand due China’s economic growth for the extension of infrastructure and construction of housings. This kind of ‘day-mining’ may have a serious impact into the livelihood of stenotypic fishes. Especially balitorid species are susceptible to turbid waters.
Where does the name Yuanjiang came from?
While the name ‘Honghe’ and its English translation ‘Red River’ is an allusion to the reddish coloration of the water body during the rainy season, when the water is heavily silt laden through intense rain falls, the ancient Chinese name ‘Yuanjiang’ has a much more interesting root; the name ‘Yuanjiang’ originates from giant softshell turtles used to occur in the Chinese part of the Red River basin in ancient times. There were four different turtle species roaming the waters, all of them called ‘惵‘ (= ‘yuan’). These species are Pelochelys bibroni, Rafetus swinhoe, Trionyx steindachneri and Trionyx siliensis. Nowadays just Trionyx steindachneri seem to have survived. Read this online article about the naming of the Yuangjiang and survival of the residual populations of softshell turtles in the Red River basin.
Link to Swallow Cave photographs, Yuanzidong, Yunnan Province, China - no fish.
Link to Rice Terrace photographs, along road Xinjie - Panzhihua, Yunnan Province, China - no fish.
Red River
The first fishing activities on this excursion commenced along the Red River; one of the largest, historically important and mighty rivers in China. The Red River has a total length of around 1200 km. It originates in Yunnan province, SW China, flows southeastwards, passes the Vietnamese capital Hanoi before it empties into the Gulf of Tonkin in North Vietnam. The Chinese name of the Red River is Yuanjiang or Honghe, the Vietnamese is Hong Ha or Song Hong. More information about this river are linked here.
We were fishing in at least five spots; all of them are allocated within the Red River basin with a slight focus on the Black River. I definetely have to schedule an excursion with more intense fishing along the Red River itself in the future.
The Δ symbols indicate the rough location we were operating.
EW-CN 62-09, Huangcaoling
Our spot at Huangcaoling, coded EW-CN 62-09, featured a typical mid sized tributary during the dry season; clean and moderate-fast flowing, cool water. We measured water parameters as follows: 18 ºC, 7.8 pH, 260 µS/cm. As you can see from the picture the anticipated water masses during the rainy must be tremendous. On one hand the Red River is notorious for its floods, on the other it provides fertile land downstream for rice crops cultivation.
Located in Yuanyang County, Honghe Prefecture we caught gobiids and balitorids using common hand push nets.
We collected a couple of Vanmanenia at EW-CN 62-09; all of them just 10 mm TL long. Note the mid-dorsal golden stripe and the adiposal dorsal and ventral crests. An evidence for the close relationship of balitorid and nemacheilid loaches.
We brought them back home alive, nursed them well. They went thorugh a couple of different color patterns before they obtained the mature coloration. Finally these fishes could be identified as Vanmanenia striata Chen, 1980. Juvenile coloration seem to be virtually identical to those of Vanmanenia tetraloba (Mai, 1978). Vanmanenia striata seems to be restricted to tributaries affluent to the Red River, while V. tetraloba occurs within the Black River subbasin (Lixianjiang River subbasin).
This gobiid is new to science. I refer to it as Rhinogobius sp. G1.
Rhinogobius sp. G1 is a rather common species dwelling beneath the rocks. We push-net them using foot and hand to drive them into the net. Unfortunately I just managed to bring back home alive one female, hence, all my breeding dreams vanished. It seem to be a land-locked species and shall follow the ‘developed-egg’ strategy, means the fry may go to benthic status as soon as they are hatched. They shouldn’t undergo a pelagic larval phase as a plenty of estuarine species have.
Photograph shows a nuptial male.
The lateral close up unveils dark red vermiform pattern along the cheeks and opercula. This species strikingly differs in morphometrics and meristics from all other hitherto known Red River species.
EW-CN 64-09, Zhaoladianshan
The Niukonghe River 牛孔河 was fished around 1 km before its influx into the Sinanjiang River 泗南江. We stayed here until dusk came. It was another typical small sized stream featuring clean and cool water; parameters as follows: 17 ºC, 8.4 pH, 120 µS/cm.
I only employed hand push nets in the riffles.
Two adult and a juvenile of Vanmanenia tetraloba in the container.
Zhaoladianshan featured fantastically colored and conditioned specimens of Vanmanenia tetraloba (Mai, 1978). Note the highly contrasted black body bars and yellow unpaired finnage. Cold overwintering temperatures may be the key to successful aquarium maintenance and to gonad ripening.
This is Schistura laterivittata (Zhu & Wang, 1985), originally described from the Babianjiang River. The fact sheet is linked here.
The photograph on the left shows the impressive main channel of the Black River, which is the major tributary to the Red River. Its affluent is located very much downstream in northern Vietnam. The Chinese name of the stream is Lixianjiang 李仙江.
