Found mainly in the mainstream of large rivers. In the Mekong it is nearly restricted to the Mekong mainstream. Found below Mun-Chin River to the Khone Falls (Ref. 37772). Exclusive or nearly exclusive fishing for the species occurs only during the upstream reproductive migrations and actual spawning periods in the area near the Lee Pee Waterfalls in southern Laos. Farther upstream the fishery occurs at progressively later times. This important fisheries species is under serious longterm decline and this decline evidently is basinwide and the most obvious (but not necessarily only) reason is overfishing with gillnets during the reproductive migrations and spawning periods (Ref. 10431). Found mainly in deep slow reaches of the Mekong basin at Hee Village, Muang Mouan; undertakes upstream migration in November-January/February at Hee Village, Muang Mouan (Ref. 37769). Highly esteemed expensive food fish, locally consumed. Migrates upstream in October-December; according to Ban Hang Khone fishermen stock has declined 90% of 1970 level (Ref. 9497). Also undertakes downstream migration during the wet season in June-July through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). One of the favorite food fish; meat is considered excellent; eggs are especially priced; made into "som kai pba eum", in which one part of fish eggs with salt and ground rice added is mixed with 15 parts of meat; the uncooked mix is placed in earthen jars to ferment for a number of days before eating (Ref. 12369). In the past, som kai pba eum was eaten mainly in the village where it was made, or occasionally sold at local festivals and celebrations (Ref. 12369). Catch, trade and transportation forbidden under the Fiat-Law on Fishery Management and Administration No. 33 KRO.CHOR of 19 March 1987, as "probatus jullieni". May be caught out of spawning season for local consumption, but cannot legally be caught during the spawning season or traded on a commercial basis at any time under the Lao Ministry of Agriculture and Forestry decree 118/MC 1989, updated 1991 (Ref. 12369). Becoming rare and locally extinct (Ref. 43281). Museum: Mekong at Ban Hang Khone, just below Khone falls, CAS 94159, 95476 (Ref. 5515). Also Ref. 2686, 4792, 7427, 12369, 30857, 36654, 37767, 37770, 44002, 56905.