Riverine Fisheries of Assam

Brahmaputra River System:

The Brahmaputra River is a transboundary river flowing through the Arunachal Pradesh and Assam in North-East and traversing around 1625 km in Tibet and 918 km in India before flowing through Bangladesh for 337 km and finally ending up into the Bay of Bengal with a joint channel with river Ganga. This river flows through the Arunachal Pradesh in a north-south direction for 278 km (Siang River) and across the east-west ranges of the Himalayas. Upon entering the plains of Assam, the Siang River (also known as Dihang) meets two rivers namely Dibang and Lohit near Oiramghat (Lakhimpur District) and the combined river takes of Brahmaputra. In Assam, it flows westward for about 640 km up to Dhubri then abruptly turns south and enters Bangladesh. The sub-Himalayan mountain ranges of Bhutan and Arunachal Pradesh in the north and northeast, the Nagaland Hills in the east and southeast, the Hills zone of Assam and Meghalaya in the south, and the plains of Bangladesh to the west shares borders with mighty Brahmaputra River Valley. These mountains/hills have given rise to numerousfast-flowing streams/rivers flowing down the gradient and ultimately teaming up with the river Brahmaputra, which has 42 tributaries with 27 on the north and 15 on the south bank.

Fish Diversity:

The pattern of fish distribution and abundance varies considerably in different stretches of the river due to varied topography and climatic conditions. In the upper stretch extending up to Dibrugarh, commercial catches are dominated by Labeo gonius, Wallago attu, L. bata, Notopterus notopterus, etc. Indian major Carps (L. rohita, Gibelion catla, Cirrhinus cirrhosa, L. calbasu) are generally less abundant. In the lower reaches, Indian major Carps, minor Carps, catfish, and Tenualosa ilisha are abundant. Commercially important fish species of the river Brahmaputra include Indian major Carps (Labeo rohita, Gibelion catla, Cirrhinus cirrhosa, L. calbasu), minor Carps(L. gonius, L. bata, Bangana. dero, and Cirrhinus reba), major catfishes (Wallago attu, Sperata seenghala, S. aor, Rita rita, Pangasius pangasius, Bagarius bagarius), minor catfishes (Eutropiichthys vacha, Ompok pabda, Clupisomagarua, Ailiacoila, Setipinna phasa, Mystus tengara, M. bleekeri, M. cavasius), knife fishes (Chitala chitala, Notopterus notopterus), Hilsa (Tenualosa ilisha) and miscellaneous species (Cabdio morar, Gudusia chapra, Barilius barilius, Puntius spp., Trichogaster spp.).

Barak River System:

The Barak River flows 900 kilometres (560 mi) through the states of Manipur, Nagaland, Mizoram and Assam in India. Further it enters Bangladesh where it is known by the name of the Surma and the Kushiyara and later called the Meghna before receiving the combined flow of the Ganga and the Brahmaputra. It flows into the Bay of Bengal via Bangladesh. Of its length 524 km (326 mi) is in India, 31 km (19 mi) on the Indo–Bangladesh border and the rest is in Bangladesh. The upper part of its navigable part is in India — 121 km (75 mi) between Lakhipur and Bhanga, declared as National Waterway 6, (NW-6) since the year 2016. It drains a basin of 52,000 km2 (20,000 sq mi), of which 41,723 km2 (16,109 sq mi) lies in India, 1.38% (rounded) of the country. The water and banks host or are visited by a wide variety of flora and fauna. The principal tributaries are all in India: the Sonai (or Tuirial), the Jiri, the Tlawng (or Dhaleswari, or Katakal), the Jatinga, the Longai and the Madhura.

Fish Diversity: Some common fish species of Barak rivers are listed below

1	Chitala chitala	19	Rita rita
2	Hilsa ilisa	20	Mystus cavasius
3	Gudusta chapra	21	Aorichthys seenghala
4	Hypothalmichthys molitrix	22	Ompok bimaculatus
5	Securiculagora	23	Wallago attu
6	Salmostoma baccalia	24	Ailia coila
7	Barilius barala	25	Clupisoma garua
8	Danio aequipinnatus	26	Eutropiichthys vacha
9	Amblypharyngodon mola	27	Eutropiichthys murius
10	Neolissochilus hexagonolepis	28	Bagarius bagarius
11	Osteobroma cotio	29	Nangra nangra
12	Puntius sophore	30	Glyptothorax telchitta
13	Cirrhinus mrigala	31	Chaca chaca
14	Catla catla	32	Rhinomugil corsula
15	Labeorohita	33	Mastacembelus armatus
16	Labeocalbasu	34	Chanda nama
17	Schisturamultifasciatus	35	Glossogobius giuris
18	Botia dario	36	Channa punctatus

Conclusion:

Most Indian rivers, at present, are highly regulated numerous multipurpose reservoirs for irrigation, water supply, hydropower are under construction, along with many barrages for water diversion. Many long reaches of the river go completely almost dry for the greater part of the year and receive water only during monsoon due to diversion and abstraction of water. In recent times, the rivers are also becoming the dumping grounds for industrial effluents, agrochemicals, pesticides and domestic wastes. Indiscriminate killing and over-exploitation of juvenile and brood fishes is another big concern for the sustainability of these river basins. Therefore, appropriate and need-based management options should be applied when required for sustainable development andconservation of these open water systems by involving all the stakeholders and integrating their goals and interest.