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Tenualosa ilisha 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Actinopterygii Clupeiformes Clupeidae

Scientific Name: Tenualosa ilisha (Hamilton, 1822)
Regional Assessments:
Common Name(s):
English Hilsa
Synonym(s):
Clupanodon ilisha Hamilton, 1822
Clupea palasah Cuvier, 1829
Taxonomic Source(s): Eschmeyer, W.N. (ed.). 2014. Catalog of Fishes. Updated 10 March 2014. Available at: http:// research.calacademy.org/research/ichthyology/catalogfishcatmain.asp.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2014
Date Assessed: 2013-01-23
Assessor(s): Freyhof, J.
Reviewer(s): Datta, N.C., Dey, S.C., Jha, B.R. & Allen, D.J.
Justification:
Previous Assessment

The species is widespread, but there have been serious declines in some major populations of the species due to over-exploration by commercial fisheries (especially in parts of India and Nepal), pollution in Iraq and India, and disruption of migration routes by dam development. Is is still assessed as Least Concern, but further work is required to understand the species population and distribution, and the impact of fishery activities and other threats.



The Gulf

This species is only known from the northern Gulf, and has experienced at least a 70% decline in Iraq and a 90% decline in Kuwait based on landings over the past 10 years, with no indication of decrease in effort.  However, catches in Iran , which by number represent the majority of the region's population, have been relatively stable around 4000-5000 metric tonnes over the past 10 years. Based on combined landings in the region, there has been an estimated 20-25% decline in this species range in the Gulf over the past 10 years. In addition to fishing, this species is also threatened by increasing salinity and extensive loss of marsh habitat due to dam construction.This species is listed as Near Threatened. However, there is special concern for this species both Kuwait and Iraq, given that its range has contracted by at least 30% over the past 20 years in this part of its range in the Gulf. Assessors:    Farhad Kaymaram,  Ebrahim Abdulqader, Hussain Al-Nazry, James Bishop, Mohsen Al-Husaini, Mustafa Al-Mukhtar, Stanley Hartmann, Md. Samsul Alam, Khalid Al-Khalaf. Date Assessed: February 23, 2014  Facilitator: Beth Polidoro

This species is relatively widespread in the Indian Ocean where it is common and abundant in some areas.  It usually contributes a significant percentage to the total catch of fisheries within The Gulf, especially in Kuwait, Iraq, and Iran.  This species is also highly sought after as a food source in other countries, including India, Pakistan, Bangladesh, and Myanmar.  However, recent landings of T. ilisha and Pampus argenteus in Kuwait have each declined by 89% from over 1,000 t in 1995 to just over 100 t in 2004.  These declines are most likely a result of over-fishing rather than a decrease in fishing effort, especially for T. ilisha; this species is very vulnerable in the Shatt al-Arab river (limited entrances, low river flow) due to gill net blockage of migration routes to spawning grounds in the Tigris, Euphrates, and Karun Rivers.  Other anthropogenic alterations (pollution, dams, coastal development) have limited natural fresh water flow and permanently damaged spawning grounds for this species.  Despite recent declines, this species is likely to experience increased fisheries pressure due to declines in other important food-fish species in the region (e.g. Pampus argenteus) and the lack of effective regulations.  There are no known, species-specific conservation measures in place for this species but there are several marine protected areas throughout its distribution.  Therefore, Tenualosa ilisha is listed as

Geographic Range [top]

Range Description:Previous Assessment

The species is known from the northern part of the India Ocean (from the Persian Gulf eastward to the Andaman coast of Myanmar, including western and eastern coasts of India, and western (Andaman) coats of Thailand and Malaysia; C. Vidthayanon pers. comm. 2010). Reported from Viet Nam (Gulf of Tonkin), the Tigris River basin and probably present in other rivers of southern Iran.


The Gulf

This species is restricted to the northwestern Gulf, north to the estuary of the Shatt al-Arab River in Iraq and other rivers in Iran.  It ascends the Shatt al-Arab River to the great marsh area north of Basrah City, Iraq.  The upper limit of its northern distribution is Al-Hammer Marsh, 180 km north of Basrah City (Jawad et al. 2004), and up to 220 km inland to the  Karun River and its tributaries in Iran. This species is also found in Kuwait Bay (Al-Yamani et al. 2007, Blaber 2009).

Historically, T. ilisha was found to Qalaat Salah on the Tigris River and to Al-Fahod on the Euphrates River about 150-180 km north of Basrah (Al-Daham, 1977).


Global Distribution:  
Tenualosa ilisha occurs in the Indian Ocean from The Gulf, east to the coasts of India, as far as Myanmar (Burma).  It has also been reported from the Gulf of Tonkin (Viet Nam) as well as the Tigris River and probably other rivers of southern Iran (Nguyen and Nguyen 1994, Coad 1995).
Countries occurrence:
Native:
Bangladesh; India; Iran, Islamic Republic of; Iraq; Kuwait; Malaysia (Peninsular Malaysia); Myanmar; Oman; Pakistan; Qatar; Saudi Arabia; Sri Lanka; Thailand; United Arab Emirates; Viet Nam
FAO Marine Fishing Areas:
Native:
Indian Ocean – western; Indian Ocean – eastern
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Previous Assessment

No information on population trends across the species range. Due to the construction of dams, weirs, etc, its fishery in many rivers in India has shown marked decline as these hydraulic structures pose obstruction in upriver migration of the fish for breeding. Catches of Tenualosa ilisha in India have declined rapidly, and declines have also been reported from Iraq and Bangladesh.


The Gulf
In 1997 there were 1034 tonnes, to 73 tonnes in 2012 (CSO Kuwait Landings - get reference from James), which represents a more than 90% decline. Landings for this species in marine and freshwater rivers Iran may be relatively stable were 5400 tonnes in 2011 and 4400 tonnes in 2012 (get prior years from Farhad). Landings in Iraq have also declined from representing 18% of the catch to 10% of the total catch from 2007 to 2011, while landings have declined about 70%  from 1323 tonnes to 375 tonnes over the same 5 years in Iraqi marine waters (Mohammed and Hassan Trend of the Artisanal Fishery in Iraqi Marine Waters, Arabian Gulf during 1965 to 2011 in press).It is estimated that freshwater catches would show an equal or higher decline. Effort has likely increased for this species after 2004 in Iraq and Iran, and has not declined in other parts of its range. This species primarily spawns from March to October, with a peak  in May, in both Iran and Iraq. 

Dam building in Turkey and Iran, in addition to loss marsh habitat  in Iraq has drastically affected this species.  In Kuwait Bay and in the northern Gulf, the salinity has increased to 45 ppt due to reduced discharge of the Shatalarab River and desalinization. Historically, this species used to range further north of the Al Hamar Marsh in Iraq and the Bahman Shir River in Iran. It is estimated that this species range has contracted more than 30% in Iraq over the past 20 years due to increasing salinity, loss of marshes and upstream dams in the Tigris and Euphrates.

Tenualosa ilisha and three other species accounted for over 80% of the total catches in the eastern Al-Hammar Marsh from October 2005 to September 2006.  T. ilisha contributed 10.1% to the total catches, and it was present for 7 months during this study (Hussain et al. 2009).


Landings of T. ilisha and Pampus argenteus in Kuwait have each dropped by 89% from over 1,000 t in 1995 to just over 100 t in 2004.  These declines are most likely a result of over-fishing rather than a decrease in fishing effort, especially for T. ilisha; this species is very vulnerable in the Shatt al-Arab river (limited entrances, low river flow) due to gill net blockage of migration routes to spawning grounds in the Tigris, Euphrates, and Karun Rivers (Al-Yamani et al. 2007). 



Current Population Trend:Decreasing
Additional data:
Continuing decline of mature individuals:Unknown
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:Previous Assessment
Marine, pelagic and schooling in coastal waters, euryhaline, anadromous, ascending rivers for as much as 1,200 km, but usually about 50 to 100 km. Breeds mainly in rivers, in some cases far up (400 km up to Mahanadi system, and even to Agra and Delhi and over 1,000 km up the Ganges), but elsewhere only to about 50 km or less. Younger fishes may breed in the tidal zone of rivers. In some rivers the migration is restricted by dams. In some large rivers as the Ganges migratory and resident populations exist (Whitehead 1985).

The Gulf
In addition to Previous Assessment:  Tenualosa ilisha is a pelagic-neritic, anadromous species that occurs in tropical waters to a depth of 200 m (Whitehead 1985, Riede 2004).  It is mainly a filter feeder that consumes plankton, but also practices grubbing on muddy bottoms.  Spawning mainly occurs in rivers during the southwest monsoon and from January to February/March.  Artificial propagation of this species has been partially successful in India (Talwar and Jhingran 1991).  This species is known to be a fast swimming, at times covering up to 71 km in one day (Pillay et al. 1963).  Maximum standard length for this species is 60.0 cm or 600 mm male/unsexed (Whitehead 1985); maximum published weight is 680.0 g (Talwar and Jhingran 1991).

This species has the ability to spawn multiple times during its spawning season from May to August.  Its absolute fecundity is estimated to range from 450,000 to 1,600,000 eggs per female, but may reach 2,000,000 depending on the size of the individual.  Size at first maturity within the Shatt al-Arab River range between 200 mm and 550 mm in length (TL/SL not specified) (Jawad et al. 2004).

Al-Saad et al. (2008) described the up-stream spawning migration of Tenulosa ilisha from The Gulf to the Shatt al-Arab river to occur from early March to late October, with a peak between the middle of April to June.  Spawning migrations of this species are triggered by numerous environmental factors, but rising water temperatures during the spring and summer seem to have the most influence throughout its distribution (Al-Saad et al. 2008)..

The average size of this species in the Shatlara Arab in Iraq is also decreasing, in 2013 the largest size was estmated to be less than 50 cm. The females mature at about 1 year of age, and the male at less than one year. However, historically this species has matured at 3 years for females and 2 years for males (Mustafa Al-Mukhtar pers comm. 2014). This species is very difficult to age, and may only live to be 4 or 5 years of age (Mohsen Al-Husaini pers comm. 2014). This species has a generation length of approximately 2-3 years. 
This species may live as long as 6 years in Bangledesh - Meghma River, but 90% of the catch is about 4 years old (Amhed et al. 2008).
Systems:Freshwater; Marine
Movement patterns:Full Migrant

Use and Trade [top]

Use and Trade: Previous Assessment

The species is of tremendous fishery importance in India. It is highly valued, particularly in West Bengal, Andhra Pradesh and Tamil Nadu. The average size of an anadromous mature female is 38-46 cm, males generally smaller. The maximum recorded size for females is 60 cm with a weight of 2.49 kg, for males 43 cm and 0.68 kg.
        
In recent years, catches in India have declined rapidly. The catches in Bangladesh have also been reported as declining (B.R. Jha, pers. comm. 2009).



The Gulf

Tenualosa ilisha is of minor commercial importance to the fisheries industry and is experimental in aquaculture (Talwar and Jhingran 1991, FAO 1992).  It is marketed fresh of dried-salted (Whitehead 1985).  Jawad (2006) listed T. ilisha as the ninth most important food-fish species out of fourteen targeted species in the Iraqi marshlands.


During the 2004 fishing season, 135 metric tons of this species were harvested by Kuwait's T. ilisha fishery (gill nets).  In 2001, < 2,000 metric tons of this species were harvested by Iraq's fishery (gill nets).  This species is harvested by traps, weirs, and gill nets in the southern waters of Iran.  During the 1997 fishing season, 400 metric tons were harvest in Iran.  T. ilisha is also targeted in Pakistan, India, Bangladesh, and Myanmar with the largest catches harvested from Bangladesh; 255,000 metric tons of this species were harvested in Bangladesh during the 2004 fishing season using inland and marine gill nets (Blaber 2009).

A survey of the fisheries in Fao, Basrah, Iraq during the 1990-2006 fishing seasons concluded that T. ilisha made up 38.9% of the total catch from 1990-2002, and only 5.1% of the total catch from 2003-2007.  Previous records revealed that this species made up 56.9% of the total catch from 1965-1973.  Prices for this species ranged from $0.5-1 for small fish, $1.5-2 for intermediate sized fish, and $2.5-3 for large fish at wholesale prices (Al-Dubakel 2011). 

From 1995 to 1999 the average annual exploitation rate for T. ilisha was 0.52 for all marine waters surrounding Iraq.  In recent years, fishing effort for this species and others in this region have increased as stock numbers have decreased; Jabir (2005) found that the rate of exploitation of T. ilisha was 0.8 within the Shatt al-Arab river (Al-Dubakel 2011).

Landings of T. ilisha and Pampus argenteus in Kuwait have each dropped by 89% from over 1,000 t in 1995 to just over 100 t in 2004 (Al-Yamani et al. 2007).

Threats [top]

Major Threat(s): Previous Assessment

Catches in India have declined rapidly, and declines have also been reported from Iraq and Bangladesh. Declines are thought to be the result of over-fishing, industrial pollution, which causes large-scale mortality of fish eggs and larvae, and especially dams, such as the Farakka barrage in the Ganges River) which impact the species spawning migrations (Rahman 2006). Artificial propagation of the species by egg stripping has been partially successful in India.



The Gulf

Tenualosa ilisha is of minor commercial importance to the fisheries industry and is experimental in aquaculture (Talwar and Jhingran 1991, FAO 1992).  It is marketed fresh of dried-salted (Whitehead 1985).  Jawad (2006) listed T. ilisha as the ninth most important food-fish species out of fourteen targeted species in the Iraqi marshlands.

During the 2004 fishing season, 135 metric tons of this species were harvested by Kuwait's T. ilisha fishery (gill nets).  In 2001, < 2,000 metric tons of this species were harvested by Iraq's fishery (gill nets).  This species is harvested by traps, weirs, and gill nets in the southern waters of Iran.  During the 1997 fishing season, 400 metric tons were harvest in Iran.  T. ilisha is also targeted in Pakistan, India, Bangladesh, and Myanmar with the largest catches harvested from Bangladesh; 255,000 metric tons of this species were harvested in Bangladesh during the 2004 fishing season using inland and marine gill nets (Blaber 2009).

A survey of the fisheries in Fao, Basrah, Iraq during the 1990-2006 fishing seasons concluded that T. ilisha made up 38.9% of the total catch from 1990-2002, and only 5.1% of the total catch from 2003-2007.  Previous records revealed that this species made up 56.9% of the total catch from 1965-1973.  Prices for this species ranged from $0.5-1 for small fish, $1.5-2 for intermediate sized fish, and $2.5-3 for large fish at wholesale prices (Al-Dubakel 2011). 

From 1995 to 1999 the average annual exploitation rate for T. ilisha was 0.52 for all marine waters surrounding Iraq.  In recent years, fishing effort for this species and others in this region have increased as stock numbers have decreased; Jabir (2005) found that the rate of exploitation of T. ilisha was 0.8 within the Shatt al-Arab river (Al-Dubakel 2011).

Fisheries targeting this species in The Gulf (Kuwait, Iraq and Iran) have shown significant declines due to anthropogenic alterations that have caused the reduction of spawning areas.  Restoration of these areas and reestablishment of the natural flow patterns are necessary to maintain the fisheries and T. ilisha population in this region (Blaber 2009).

Landings of T. ilisha and Pampus argenteus in Kuwait have each dropped by 89% from over 1,000 t in 1995 to just over 100 t in 2004.  These declines are most likely a result of over-fishing rather than a decrease in fishing effort, especially for T. ilisha; this species is very vulnerable in the Shatt al-Arab river (limited entrances, low river flow) due to gill net blockage of migration routes to spawning grounds in the Tigris, Euphrates, and Karun Rivers (Al-Yamani et al. 2007).

Conservation Actions [top]

Conservation Actions: Previous Assessment

None required at present.



The Gulf

There are no known, species-specific conservation measures in place for Tenualosa ilisha.  There are several marine protected areas within its distribution.

Citation: Freyhof, J. 2014. Tenualosa ilisha. The IUCN Red List of Threatened Species 2014: e.T166442A1132697. . Downloaded on 23 September 2018.
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