Probarbus jullieni, Isok barb : fisheries, aquaculture, gamefish

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Probarbus jullieni Sauvage, 1880

Isok barb
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Probarbus jullieni
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Classification / Names Common names | Synonyms | Catalog of Fishes(genus, species) | ITIS | CoL | WoRMS | Cloffa

Actinopteri (ray-finned fishes) > Cypriniformes (Carps) > Cyprinidae (Minnows or carps) > Probarbinae
Etymology: Probarbus: Greek, pro = first, in front of + Latin, barbus = barbel (Ref. 45335).  More on author: Sauvage.

Environment: milieu / climate zone / depth range / distribution range Ecology

Freshwater; brackish; demersal; potamodromous (Ref. 37770).   Tropical; 28°N - 5°N

Distribution Countries | FAO areas | Ecosystems | Occurrences | Point map | Introductions | Faunafri

Asia: Mekong, Chao Phraya and Meklong basins of Indo-China and Thailand, and the Pahang and Perak basins of Malaysia (Ref. 7427). Catch, trade and transportation forbidden in Laos (Ref. 12217). International trade banned (CITES I, since 1.7.75).

Size / Weight / Age

Maturity: Lm ?  range ? - ? cm
Max length : 150 cm SL male/unsexed; (Ref. 30857); common length : 28.0 cm TL male/unsexed; (Ref. 2073); max. published weight: 70.0 kg (Ref. 12369)

Short description Morphology | Morphometrics

Dorsal soft rays (total): 13; Anal soft rays: 8. Differs from P. labeamajor in having only 5 (instead of 6) stripes between lateral line scale row and dorsal fin base; lips not enlarged, free posterior margin of lower lip interrupted at midline; large adults without mentum; maxillary barbel invariably well developed, length one-third or more of eye diameter. The only species in which body stripes may extend to every scale row, but this only occurs in some larger and more darkly pigmented individuals. P. labeamajor and P. labeaminor have no more than three stripes below lateral line scale row, and the abdomen is uniformly white. Adults and larger juveniles of P. jullieni usually have much more red and sometimes yellow coloration on head, body, and fins than the other two species. Scale rows between lateral line scale row and pelvic fin 4.

Biology     Glossary (e.g. epibenthic)

Inhabits mainly the mainstream of large rivers (Ref. 10431), with sand or gravel substrates and abundant mollusks populations (Ref. 12693). Occurs in deep slow reaches (Ref. 37769). 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 (Ref. 6459). 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 (Ref. 37770). 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 (Ref. 37770). Egg is buoyant, yellow and 2 mm in diameter. Hatching occurs in 32 hrs at 23°C (Ref. 6459). An excellent foodfish, sometimes consumed raw, but rather scarce so it fetches a high market price (Ref. 2686). Eggs are especially priced (Ref. 12369). Used to be cultured commercially in Thailand (Ref. 7306). 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 (Ref. 10431), but mostly caught during November-January spawning migration, when it is by far the most important species in fisheries catch (Ref. 12369). 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 (Ref. 10431). Attains 70 kg or more, but mostly marketed size nowadays are 5-20 kg (Ref. 12369).

Life cycle and mating behavior Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae

Main reference Upload your references | References | Coordinator | Collaborators

Roberts, T.R., 1992. Revision of the Southeast Asian cyprinid fish genus Probarbus, with two new species threatened by proposed construction of dams on the Mekong River. Ichthyol. Explor. Freshwat. 3(1):37-48. (Ref. 7427)

IUCN Red List Status (Ref. 123251)

  Critically Endangered (CR) (A2d); Date assessed: 29 January 2019

CITES (Ref. 123416)

CMS (Ref. 116361)

Not Evaluated

Threat to humans


Human uses

Fisheries: commercial; aquaculture: experimental; gamefish: yes
FAO - Aquaculture: production; ; Publication: search | FishSource |

More information

FAO areas
Food items
Food consumption
Common names
Spawning aggregation
Egg development
Larval dynamics
Aquaculture profile
Allele frequencies
Mass conversion
Stamps, Coins Misc.
Swim. type
Gill area


Special reports

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Internet sources

Aquatic Commons | BHL | Cloffa | Websites from users | Check FishWatcher | CISTI | Catalog of Fishes: genus, species | DiscoverLife | ECOTOX | FAO - Aquaculture: production; ; Publication: search | Faunafri | Fishipedia | Fishtrace | GenBank: genome, nucleotide | GloBI | Google Books | Google Scholar | Google | IGFA World Record | MitoFish | Otolith Atlas of Taiwan Fishes | Public aquariums | PubMed | Reef Life Survey | Socotra Atlas | Tree of Life | Wikipedia: Go, Search | World Records Freshwater Fishing | Zoobank | Zoological Record

Estimates based on models

Phylogenetic diversity index (Ref. 82805):  PD50 = 0.6250   [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00447 (0.00175 - 0.01142), b=3.12 (2.89 - 3.35), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref. 93245).
Trophic level (Ref. 69278):  3.2   ±0.40 se; based on food items.
Resilience (Ref. 120179):  Very Low, minimum population doubling time more than 14 years (Preliminary K or Fecundity.).
Vulnerability (Ref. 59153):  Very high vulnerability (87 of 100) .
Price category (Ref. 80766):   Unknown.
Nutrients (Ref. 124155):  Calcium = 117 [58, 232] mg/100g ; Iron = 0.684 [0.408, 1.422] mg/100g ; Protein = 17 [16, 18] % ; Omega3 = 0.345 [0.135, 0.903] g/100g ; Selenium = 82.2 [36.1, 183.7] μg/100g ; VitaminA = 29.7 [8.4, 109.2] μg/100g ; Zinc = 1.06 [0.65, 1.72] mg/100g (wet weight);