|Scientific Name:||Probarbus jullieni|
|Species Authority:||Sauvage, 1880|
Barbus pahangensis Duncker, 1904
Cyclocheilichthys jullieni Sauvage, 1880
|Red List Category & Criteria:||Endangered A2abcd ver 3.1|
|Assessor/s:||Hogan, Z. & Baird, I.|
|Reviewer/s:||Allen, D. & Juffe Bignoli, D.|
The species occurred historically in the Mekong, Chao Phraya and Meklong basins in Southeast Asia and the Pahang and Perak basins of Malaysia. Self-sustaining populations of the species may no longer occur in the Chao Phraya or Meklong River Basins. In the Pahang River Basin of Malaysia, the species is either extirpated or extremely rare (Baird 2006). Populations have dropped significantly in the Perak River Basin due to hydropower development and subsequent changes in stream hydrology (Baird 2006). Roberts (1992) and Baird (2006) state that the Mekong River supports the last relatively healthy population.
As recently as 1989, the species was reported as “extremely abundant” in the Mekong, but subsequent accounts indicate a significant drop in abundance since 1989 (Roberts and Warren 1994; Roberts and Baird 1995; Singhanouvong et al. 1996). Populations in many locations in Lao PDR appear to have declined significantly (Baird 2006). Cambodian fishers (age 40+, n=43) estimate that overall catches have declined by 71% in the Cambodian Mekong since 1985 (Hogan unpublished data). The average size of fish has dropped by 50% between 1985 and 2006. One fisher from Kratie, Cambodia reported that he caught a fish weighing 60 kg in 1967. In recent times, fishers report that the largest fish weigh about 20 kg.
The species is a large-bodied, long lived, migratory species that heavily exploited for food, both subsistence and commercial fisheries throughout its range, but especially in the Mekong. The species is also impacted by habitat loss, degradation, and fragmentation (Baird pers. comm.). A population decline of at least 50% is inferred from catch data at Khone Falls (Lao PDR), local knowledge of fishermen in Cambodia, loss of local populations, and a decrease in extent of occurrence. The species is assessed at Endangered A2abcd.
Mainstream dams on the Mekong would further impact species habitat, migrations, and reproductive recruitment. The species does not survive in reservoirs.
|Range Description:||Historically recorded from the Mekong in Thailand, Viet Nam, Cambodia and Lao PDR (to at least northern Laos), and from Malaysia (the Pahang and Perak basins). In Thailand it is known from the Menam and Chao Phraya basins.
In the Pahang River Basin of Malaysia, the species is either extirpated or extremely rare, and populations have dropped significantly in the Perak River Basin due to hydropower development and subsequent changes in stream hydrology (Baird 2006). Roberts (1992) and Baird (2006) state that the Mekong River supports the last relatively healthy population of the species. As recently as 1989 it was reported as “extremely abundant” in the Mekong, but subsequent accounts indicate a significant drop in abundance since (Roberts and Warren 1994; Roberts and Baird 1995; Singhanouvong et al. 1996). Populations in many locations in Lao PDR appear to have declined significantly (Baird 2006).
Native:Cambodia; Lao People's Democratic Republic; Malaysia (Peninsular Malaysia); Thailand; Viet Nam
|Range Map:||Click here to open the map viewer and explore range.|
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 (Roberts and Warren 1994; Baird 2006). The average weight of individual fish in catches has declined from 70 kg or more to 5-20 kg (Roberts and Baird 1995).
The species is thought to contribute around 0.3% of the total fish catch in the lower Mekong (c.3,030 tonnes per year; ICEM 2010). The species contributes 65% of a large meshed (18-25 cm mesh) fishery just below the Khone Falls in southern Lao PDR, however from 1993 to 1998 it declined from 64 to 27 fish caught per season (Baird 2006).
Healthy populations may only occur in the Mekong basin (Roberts 1992) and even there populations have been declining. Populations have been locally extirpated in the Mekong basin (Baird 2006).
The species is believed to benefit from the protection of deep water pools in the mainstream of rivers in the dry season (Baird 2006; Baird and Flaherty 2005).
In 1945, populations had been thought to have been declining for at least the last 65 years (Smith 1945) in central Thailand. Roberts and Baird (1995) reported that just below the Khone falls it had declined by 80-90% between 1970-1995. Roberts and Warren (1994) reported that at Hee Island, above the Khone Falls, 100 individuals used to be caught per day, but that only 60 were caught per day in 1992, and in 1993 only a maximum of 22 were caught per day, and 92 in the whole season. More dramatically, the fishery at Say Island in Champasak Province above the Falls, the fishery for the species crashed crashed in 1993, although in the previous year they had caught 60 fish (Roberts and Baird 1995).
In Malaysia the species has been seriously impacted by dams in the Perak basin, which have destroyed a number of spawning sites (Baird 2006).
A population decline across the species range of 50% is inferred from catch data from the Khone falls area (Baird 2006), from loss of local populations in the Mekong basin, and from information from other parts of the species range.
|Habitat and Ecology:||
Inhabits mainly the mainstream of large rivers, with sand or gravel substrates and abundant mollusc populations. Occurs in deep slow reaches. Undertakes short distance spawning and trophic migrations in the Mekong basin (Baird 2006).
Adults of the species appear to prefer main river habitats, whereas juveniles will enter floodplain habitats during the rainy season. The species is omnivorous, feeding on zooplankton, aquatic plans, fruits, invertebrates, molluscs, shrimp, and crabs (Poulsen et al. 2004; Baird 2006).
Age at maturity is unclear. Mattson et al. (2002) reports that mature males weigh 5-20 kg; mature females weigh 10-50 kg. In captivity, male broodstock mature at 2-7 kg while female broodstock mature at 5-15 kg (Mattson et al. 2002).
The species spawns during the dry season between November and February (Poulsen et al. 2004; Baird 2006). Several spawning sites have been identified within the Mekong River 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.
Young of the species move out of the Tonle Sap River and into the Mekong River in October and November (Hogan et al. 2006). Adult fish make upstream spawning migrations. One tagged individual moved 135 km upstream from the Tonle Sap River up the Mekong River (Hogan et al. 2006). “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” (Sohkeng et al. 1999).
This species is impacted by overfishing (primary the large-mesh gill net fishery; Allan et al. 2005), habitat destruction, and large dams. Passage through mainstream hydro power dams is considered "Not viable" (M.R.C. 2009), and the species does not survive in reservoirs (Baird 2006).
The species is particularly vulnerable to over exploitation since adults from spawning aggregations are targeted by fishermen on the spawning grounds (Z. Hogan pers. comm. 2011).
Research into population trends and threats to the species and its habitats is needed. Catch, trade and transportation is forbidden in Laos (Kottelat and Whitten 1996) where it is a Schedule II species (I. Baird pers. comm. 2011), and is also listed in the Red Data Book for Viet Nam (Baird 2006). International trade is banned (CITES Annex I, since 1975).
The Cambodian government is regulating the use of large mesh gill nets in northeastern Cambodia. The species reportedly benefited from freshwater conservation zones established in southern Lao PDR during the 1990’s (Baird 2006), but some of these zones may no longer exist. The species would benefit from fishing regulations to control overharvest and protected areas to safeguard spawning sites.
|Citation:||Hogan, Z. & Baird, I. 2011. Probarbus jullieni. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 10 March 2014.|
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