ICAR-Central Inland Fisheries Research Institute, Barrackpore, Kolkata-700120, India
Received Date: September 21, 2015; Accepted Date: November 26, 2015; Published Date: February 15, 2016
Citation: Gupta S (2016) Pangasius pangasius (Hamilton, 1822), A Threatened Fish of Indian Subcontinent. J Aquac Res Development 7:400. doi:10.4172/2155-9546.1000400
Copyright: © 2016 Gupta S. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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Pangasius pangasius is a catfish species which is widely distributed in India, Bangladesh, Pakistan, Myanmar, Malaya-peninsula, Indonesia, Vietnam, Java and Thailand. It is a popular food fish as having good taste with high protein, mineral and fat content in its flesh. It is also a popular game fish and recently has got its entry in ornamental fish markets too. Pangasius pangasius is very hardy in nature; has high tolerance for temperature, salinity and turbidity; but due to over exploitation, habitat degradation, water pollution, destruction of the breeding grounds etc. natural populations of this fish species are facing the threat of extinction and its now high time to take proper measures on serious note to conserve its natural population. The present report has been prepared with the aim to sum up the available information on different aspects of Pangasius pangasius along with noting down the possible measures that should be taken into consideration for its conservation.
Pangasius pangasius; Catfish; Threatened; Conservation
Pangasius pangasius (Hamilton, 1822) is a catfish species of the family Pangasiidae under the order Siluriformes. It forms a good fishery of considerable value and is used to fetch high market price as a food fish due to its good taste and deliciousness  with high protein, mineral and fat content in its flesh [2,3]. It is also popular as a game fish . Recently it has made its entry into ornamental fish markets [4,5] and has also been documented to be exported from India as indigenous ornamental fish .
Body is elongated and laterally compressed, without any scale. Head and abdomen are flat; tail is constricted behind the adipose fin but a bit extended before the caudal peduncle. Head is slightly granulated above; occipital process is used to reach to basal bone of dorsal fin; snout is fairly prominent. Eyes are in the anterior half of the head, partly on the lower surface of head. Mouth is sub-terminal; upper jaw is longer than the lower jaw; mouth gape is of moderate size. Cleft of mouth is used to reach opposite the centre of front edge of the eye. Four groups of teeth are present on the palate; palatine teeth are in a crescent row, vomarine patches are separate from or nearly confluent with those on palate. Barbels are two pairs; the maxillary pair reaches the base of pectoral fin and the mandibular pair is half as long as the head in length. First dorsal fin is with a moderately strong spine which is strongly serrated on its inner edge but finely serrated on its outer edge. Adipose dorsal fin is short, posteriorly free, and originates almost opposite to the middle of the anal fin. Pectoral fin spine is serrated, strong and as long as dorsal spine. Anal fin is large and well developed. Caudal fin is deeply forked; upper lobe is slightly the longer. Body color is silvery, darkest along the back and glossed with purple on sides; cheeks and the under surface of head is golden; caudal fin is bright yellow [1,10].
Pangasius pangasius mainly inhabits large rivers and estuaries; but can also be seen in irrigation canals, haors, baors, beels, natural depressions and even ponds especially during the monsoon period [1,16]
Adult of Pangasius pangasius is bottom feeding, carnivorous in habit; mainly prefer molluscs [13,16-21]. Apart from molluscs, fishes, insects, crustaceans etc have also been documented from the gut content of adult pangas [18,19]. Ghosh and Saigal  and Ali et al.  on the other hand have reported adult pangas as an omnivorous fish. Larval and post-larval stages of this fish species live mainly upon the planktonic food and small insects ; the fry is having selective feeding on small insects, like caddis fly cocoons (Trichoptera), small ant remains, scaly insect (moths), Haliplus larvae, amphipods and copepods while juveniles mainly consume various types of both animal (crustacean, molluscs, insects, fish etc) and plant organisms .
David  has reported that Pangasius pangasius used to attain maturity at about 54 cm size at the end of the third year age or it would take a year more to become fully ripe while Rahman  on the other side has reported that it attains maturity in the fourth year of its life. Pangasius pangasius is a seasonal spawner; David  has reported that it breeds between June and August while Rahman  has reported its breeding season in between July and October. There are diversified views regarding the spawning location of pangas; according to Pantulu , this species used to spend their adult life in the rivers and migrate to estuaries for spawning whereas David  has documented that pangas attains maturity in the estuary, then migrates and breeds in the freshwater and the young ones drift into the tidal stretch of the river where they grow and attain maturity. David  has reported Pangasius pangasius as a highly fecund fish with fecundity range of 8,85,400-58,07,560 while Ramakrishniah  has documented a range of 73,000-154,000 for the same.
Drastic decline of the natural populations of Pangasius pangasius has been reported  and numbers of factors like over exploitation, habitat degradation, water pollution, destruction of the breeding grounds and lack of proper management have been put reasonable behind this situation. Habitat loss through divergence of streams for irrigation is probably the most important factor that has threatened the species in its wide geographical range . Jhingran  has stated that dams located in the lower reaches obstruct the runs of Pangasius also is adversely affecting its stocks.
Reduction of pressure on the natural populations of any fish species under threat is the first and foremost measure to conserve the particular fish species and in this regard, captive culture of that particular fish species has been suggested by the experts as the most logical step. Pangasius pangasius has already been documented as a suitable candidate species for both mono and poly-culture with carps either in ponds or in net cages [13,24,29,30] but unavailability of fry is the main constraint towards the culture of this fish species . This problem can be solved by production of the fry in captivity following induced breeding. So far few works [15,26,31-33] have been done on induced breeding of Pangasius pangasius. Success of induced breeding in the sense of achieving maximum fry survivability depends on proper knowledge on the feeding habit and reproductive biology of that particular fish species. Till date, notable information has been documented on these two aspects of Pangasius pangasius by earlier workers [7,13,16-25].
Pangasius pangasius is a very hardy fish in nature; it can withstand long ranged temperature and salinity and high turbidity. It can also thrive well in low dissolved oxygen condition . But due to over exploitation, habitat degradation, destruction of breeding ground etc., population of this fish species is declining rapidly and is now facing the threat of extinction in nature. The problem of over exploitation can be solved by two measures: (i) by complete banning of fishing during the breeding season to provide protection to the brooders and (ii) by demarking size specific catch to save the juveniles and the existing stock. The factors which are causing habitat degradation and destruction of breeding ground must be identified and proper measures must be taken up to eradicate these problems. But before making all these measures in action, the present status of the populations of this fish species in nature to be analyzed properly as the earlier documented status was analyzed almost a decade ago. A proper survey work must be carried out following providing protection to the existing populations where in nature till they are present in numbers.
Ample information is available on feeding habit of adult Pangasius pangasius, but the same is really scarce for the larva, fry and juvenile stages. So, further study should be made to gather proper knowledge on this particular aspect; this will support proper rearing of these stages in artificial propagation and enhance survivability finally. Information available on its reproductive biology is also not much satisfactory; further study on this part will also be helpful for its artificial propagation. Last but not the least, general people should be made aware about this problem and using their support and willingness conservation programs can be arranged to get the ultimate goal.