| Biology |
Inhabits mainly
the mainstream of large rivers, with sand or gravel
substrates and abundant mollusks populations. Occurs in deep
slow reaches. Feeds on aquatic plants, insects and shelled
mollusks. Spawns in winter (late December-early February) in
big riverine deltas over sand and gravel substrate with
water current of 1.3 m/sec. Undertakes spawning and trophic
migrations in the Mekong basin. Trophic migrations occurs
throughout its occurrence range which takes place mainly at
the onset of the flood season and are mainly undertaken by
juveniles and subadults. Upstream spawning migrations take
place between October and February from Kompong Cham in
Cambodia to Chiang Khong in Thailand. At Chiang Khong ,
fishermen reported that Probarbus moves up the
tributary Nam Ta in Laos to breed in March-April. Three
Probarbus species were also reported to migrate
together, but spawn separately, in January-February at
Sungkom, Nong Khai Province in Thailand. Egg is buoyant,
yellow and 2 mm in diameter. Hatching occurs in 32 hrs at
23°C. An excellent foodfish, sometimes consumed raw, but
rather scarce so it fetches a high market price. Eggs are
especially priced. Used to be cultured commercially in
Thailand. May be caught individually or in small numbers of
any size incidentally with gillnetting and other fishing
activities, at virtually any time or place in the Mekong
mainstream, but mostly caught during November-January
spawning migration, when it is by far the most important
species in fisheries catch. In the Mekong this important
fisheries species is under serious long-term decline and
this decline evidently is basin wide and the most obvious
(but not necessarily only) reason is overfishing with
gillnets during the reproductive migrations and spawning
periods. Attains 70 kg or more, but mostly marketed size
nowadays are 5-20 kg. |
