INLAND RIVERINE FISHERIES, Fisheries,PPT

About Riverine Fisheries

1. FRM 510 INLAND fisheries resource management 2+1 RIVERINE FISHERIES

2. introduction Rivers are linear systems which show a gradient of characters along their length. Ideally the longitudinal profile of a river is concave with a steep upper portion near the source, giving way to reaches of progressively less gradient as the mouth is approached . The steep and torrential upper course is called “RHITHRON ” The flat, slow-flowing lower course is called “POTAMON”

3. RHITHRON ZONES- Characteristics They tend to show an alternation between ( i ) steep, narrow and shallow riffles or rapids and ( ii) flatter, wider and deeper reaches, termed pools Riffles have high, turbulent flow, coarse bottoms of boulders, rocks or pebbles and limited attached vegetation. Pools have lower flow, bottoms of somewhat finer material and some rooted vegetation. This zone is characterized by turbulent flow and relatively low temperatures. Generally, the water is highly oxygenated, but at low water the pool and riffle system may break up into a series of pools, whose waters may become completely depleted of oxygen.

4. Adaptations of fishes of rhithron zones The resident fish species in rhithron zones are entirely rheophilic and fall into two main groups . 1. Those species which live on or among the rocks and vegetation of the bottom and are distributed mainly in the riffles. These are of small size and are adapted to grip or cling to the substrate. Such adaptations include mouth suckers, for instance Chiloglanis , ventral friction pads as in Astroblephus or pectoral fin spines adapted as hooks as in Glyptothorax . Other species such as Mastacembelus have long sinuous shapes that enable them to twine among the holes in the rocky bottom.

5. Mastacembelus Chiloglanis Glyptothorax

6. 2. Those species such as Barbus or Salmo which are adapted to swim sufficiently fast as to resist the current and even move against it.

7. POTAMON ZONES- Characteristics Potamon reaches are with wide, flat, meandering channels, mud bottoms and considerable rooted and floating vegetation. Potamon combines both lentic and lotic waters and is more complex than rhithron . Depleted oxygen

8. Adaptations of fishes of potamon zones There are two main adaptations which enable fish to survive the conditions during low waters . 1 . Species which is specifically adapted to resisting low dissolved oxygen concentration. The adaptations may be in the form of auxiliary respiratory organs for using atmospheric oxygen as in the case of such fishes as Clarias or Notopterus .

9. The same species often have a capacity to support high temperatures. They generally have complex breeding habits with multiple spawning, a great degree of parental care, and only migrate laterally between the dry season habitat in the main river channel or the standing waters of the flood plain and the flood season habitat in the inundated area.

10. Notopterus Clarias

11. CLASSIFICATION OF RIVERS OF INDIA The rivers of India play an important role in the lives of the Indian people . The riverine system of the country comprises four groups of rivers viz. major rivers, medium rivers, minor rivers and desert rivers.

12. Major rivers The rivers with a catchment area of 20,000 km2 and above are called major rivers . There are 14 such major rivers in India. The major rivers of India can be classified into Himalayan rivers and Peninsular rivers on the basis of origin .

13. All major rivers of India originate from one of the three main watersheds. 1) The Himalaya and the Karakoram ranges 2) Vindhya and Satpura ranges and Chota nagpur Plateau in central India 3) Sahyadri or Western Ghats in western India

14. These major rivers are broadly grouped into five systems that include the followings : 1 ) The Ganga riverine system (Himalayan rivers ) 2 ) The Brahmaputra riverine system (Himalayan rivers ) 3 ) The Indus riverine system (Himalayan rivers ) 4 ) The East coast riverine system (Peninsular rivers ) 5 ) The West coast riverine system (Peninsular rivers)

15. Major river basins of the country Sl. No. Name of the river Origin Length (Km.) Catchment Area (Sq. Km.) 1. Indus Mansarovar (Tibet) 1114+ 321289+ 2. a) Ganga Gangotri Glacier ( Uttarkhand ) 2525+ 861452+ b) Brahmaputra Kailash Range(Tibet) 916+ 194413+ c) Barak & other rivers flowing into Meghna , like Gomti , Muhari , Fenny etc , 3. Sabarmati Aravalli Hills (Rajasthan) 371 21674 4. Mahi Dhar (Madhya Pradesh) 583 34842 5. Narmada Amarkantak (Madhya Pradesh) 1312 98796

16. Sl. No. Name of the river Origin Length (Km.) Catchment Area (Sq. Km.) 6. Tapti Betul (Madhya Pradesh) 724 65145 7. Brahmani Ranchi (Jharkhand) 799 39033 8. Mahanadi Nazri Town ( Chattisgarh ) 851 141589 9. Godavari Nasik (Maharashtra) 1465 312812 10. Krishna Mahabaleshwar (Maharashtra) 1401 258948 11. Pennar Kolar (Karnataka) 597 55213 12. Cauvery Coorg (Karnataka) 800 81155

17. Medium rivers A river with a catchment area between 2,000 and 20,000 km2 is categorized as Medium River. Forty four such rivers are in India with a total drainage area of 0.24 million km2 . Of these rivers, 9 rivers are interstate rivers as they flow through more than one state . Seventeen rivers flow towards west into the Arabian Sea and 23 towards east into the Bay of Bengal . Four rivers in north eastern states like Mizoram and Manipur flow into Bangladesh.

18. Minor rivers A river with a catchment area of less than 2,000 km2 is categorized as minor River. These rivers are numerous and are mostly small streams, flowing from Western and Eastern Ghats into the sea . The total drainage area of these rivers is about 0.2 million km2 .

19. Desert rivers These rivers flow for some distance and disappear in the deserts of Rajasthan . These rivers include Luni , Machai , Rupen , Saraswati , Baner and Ghaggar . The major fishes found in these rivers are Amblypharyngodon mola , Bari bendelansis , Botia geto , Labeo catla , Cirrhinus mrigala , C. reba , Labeo spp , Danio devario , D. rerio , Tor tor , Nemacheilus botia , Puntius spp , Rasbora daniconius , Mastacembelus armatus , Channa spp., Trichogaster fasciatus , Clarias batrachus , Mystus spp , Heteropneustes fossilis , Wallago attu , Notopterus spp., etc.

20. Classification of riverine fishes Based on the migratory habits, fishes occurring in Indian rivers are classified as : 1. Resident species 2. Local migrants 3 . Long distant migrants

21. Resident species The fish species which prefer to remain confined within the local territories are termed resident species. This type includes Cyprinus carpio , Notopterus spp., Channa spp., Mastacembelus spp., Garra spp , Osteobrama spp , Puntius spp , Labeo spp , Cirrhinus spp , Mystus spp , Clupisoma spp etc.

22. Local migrants The fish species which perform seasonal migrations within short distances for feeding, breeding etc., are called local migrants. This type comprises of mahseer , Indian major carps, large and medium sized catfishes (like Bagarius bagarius ), salmons, trouts etc.

23. Long distant migrants The fish species which perform regular annual migrations for feeding or spawning or for both are called long distant migrants. This type consists of Indian shad ( Hilsa ilisha ) - an anadromous fish, freshwater eel (Anguilla spp.) - a catadromous fish and catfish ( Pangasius pangasius , migrate from river to estuary).

24. World riverine resources World total river length – 2,69,000 km Area- 3,58,000 sq.km (In Asia - 1,41,000 sq.km) More number of rivers in South America

25. Indian riverine resources River length as whole (including canals) = 1,95,210 km Combined length of all major rivers (including tributaries) = 45,000 km Total catchment area = 3.12 million sq. km River basins = 113

26. Classified based on area of drainage basin Major rivers – 14 ( drainage basin >20000 Sq.Km ) Medium rivers – 44 (2000-20000 Sq. Km) Minor rivers - >102 (<2000 Sq. Km)

27. India is bestowed with 14 major, 44 medium, and numerous minor rivers that run through 2.52 lakh Kms contributes to current production of  1 Lakh ton . For optimally harnessing the potential of  riverine fisheries , the Department is focusing on conservation of indigenous fisheries resources and restoration of natural productivity by practice of river ranching and  41 Conservation and Awareness in Riverine Fisheries programme  sanctioned under Blue Revolution in 9 States /UTs.

28. Production of native species in the rivers by seed ranching of native stock, upgradation of riverine landing centers and instruments to provide financial assistance for fishermen wellbeing are being targeted. Planning is also ongoing for implementing river ranching, as a pilot-based activity under central sector scheme, in six states in two phases with total budget outlay of  Rs . 2.81 crores to ranch 1.40 crores fingerling .

29. The first phase will be launched by end of September 2022 while the second phase will begin in October 2022. To support the fishermen, the Department has sanctioned the following with an investment of  Rs 1,710 crores .

30. Most Indian rivers, at present, are highly regulated numerous multipurpose reservoirs for irrigation, water supply, hydropower have been constructed, along with many barrages for water diversion. Many long reaches of river passing through urban areas go almost completely dry for greater part of the year, except during monsoon, as the flow is diverted to irrigation and other needs, flood plains are lost and even river beds are cultivated during dry periods.

31. During the past few decades, rivers have also received increasingly large discharges of industrial effluents, agro-chemicals, and domestic wastes. All this has affected the riverine ecology and its biodiversity.

32. It is a matter of serious concern that out of the 30 rivers basins marked as global level priorities for the maintenance and protection of aquatic biodiversity, ten are from India (Cauvery, Ganga, Brahmaputra, Godavari, Indus, Krishna, Mahanadi, Narmada, Pennar , and Tapti). Though some efforts have been made towards cleaning of these rivers and enforcement of treatment of industrial effluents, there have been no systematic efforts to maintain the ecological integrity of these river systems and associated waters.

33. Cleaning of rivers The Government of India initiated River Cleaning Programme in 1985 as GAP-I (Ganga Action Plan) and GAP-II was initiated in 1993 subsequently extended to other rivers in 1995. As per the document cleaning of rivers is a mammoth task requiring the involvement of all stake-holders and also it is not a onetime efforts but a continuous one with increase in population and other stresses on such ecosystems. The main objective of the River Action Plan is to improve the water quality of the major rivers, which are the major fresh water source in the country through the implementation of pollution abatement schemes.

34. ENERGY TRANSFER AND FISH PRODUCTION POTENTIAL The rate of net energy transformation by producers and fish production potential of both the Himalayas and Peninsular rivers has been worked out by the CIFRI. The rate of energy transformation in the Ganga was 1,015 cal /m2/day in the upper zone, 4,877 cal /m2/day in middle, and 2,489 cal /m2/day in the lower zone with a fish production potential estimated at 35.2, 168.9 and 86.2 kg/ha/year respectively.

35. In Brahmaputra, the rate of energy transformation by producers was on the average 2,452 cal /m2/day in the upper zone, 2,452 cal /m2/day in middle, and 3,393 cal /m2/day in the lower zone.

36. In Mahanadi the rate of energy fixed was 3,027, 1,977 and 3,312 cal /m2/day in the three zones with the estimated fish production potential at 104.7, 68.3 and 114.6 kg/ha, respectively, potential was comparatively lower in the middle zone. In Krishna, the rate of energy fixed by producers was 2,675, 3,535 and 3,987 cal /m2/day in the three zones respectively. The fish production potential was estimated at 92.5 kg/ha in the upper zone, 122.4 kg/ha in the middle zone and 138.0 kg/ha in the lower zone showing considerable increase from upper to lower zone.

37. The fish production potential in Godavari was estimated at 128.5 kg/ha in the upper zone, 70.7 kg/ha in the middle zone and 104.4 kg/ha in the lower zone with energy transformation rate 3,715, 2,045 and 3,017 cal /m2/day, respectively.

38. In Cauvery also both rate of energy transformation and fish production potential showed a gradual increase from 2,681 cal /m2/day and 92.8 kg/ha in the upper zone to 4,164 cal /m2/day and 144.2 kg/ha in the lower zone. In Narmada both rate of energy transformation and fish production potential were comparatively higher at Amarkantak (4,507 cal /m2/day and 156.0 kg/ha).

39. Main rivers systems Ganga river system The Ganga river systems, which has a total length of about 8,047 km, is the most important river systems in India and one of the largest in the world. The main river, Ganga has its source in two headwaters ( Gangotri and Alaknanda ). Production- 389 kg/km

40. Fish and Fisheries of the Ganga river system More than 265 species of fishes have been recorded from this river system. The endangered Ganges River Dolphin ( Platanista gangetica gangetica ) is primarily found in the Ganges and Brahmaputra Rivers and their tributaries in Bangladesh, India and Nepal. The head waters of the Ganga system in the upper reaches of the Himalaya have snow trouts , catfishes, mahseers , lesser barils . Upto an elevation of 1067 m, mahseers , Tor putitora , T. tor and Acrosscheilus hexagonolepis , Bagarius bagarius and Labeo dero form main food fishes.

41. In the plains, carps, catfishes ( Osteobangrus aor and O. seenghala , collectively called tengra ), Wallago attu , Hilsa ilisha , Pangasius , Notopterus etc . constitute the fishery. The prawns, Mac robrachium malcolmsoni and Palaemon lamarrei are also found. The fishery of anadromous Hilsa have declined by 96% upstream of Farakka after construction of the Farakka Barrage in1974 due to obstruction of the migration route of the fish.

42. Brahmaputra river system The total length of this river is about 2,900 km of which about 900 km falls in India. The combined length of the river, with its 41 main tributaries, in India is about 4,000 km with a catchment area of about 580,000 km2 (195,000 km2 in India ). Production: Tezpur-Dhubri stretch (about 300 km) of this river (before it enters Bangladesh )-150 tonnes .

43. Fish and Fisheries of the Brahmaputra river system A total of 126 species of fishes belonging to 26 families have been recorded from this system. Of these, 41 species are known to have commercial importance. Catfishes (mainly Wallago attu ) and major (mainly Rohu ) and minor carps dominate the commercial catches of upper, middle and lower stretches, while the commercial catch in lower-middle stretch is primarily composed of catfish and miscellaneous catch.

44. Indus river system The Indus is one of the great rivers of the world. From its source up to the sea it is 2,000 km in length while principal tributaries the Kabul and the Swat drain Afghanisthan region on its right bank and the Jhelum, Chenab, Ravi, Sutlej and Beas as its left bank tributaries have a total stream length of 5,600 km . In India the river Indus flows at an elevation of 3,200 msl for a short distance in the town of Leh in Ladakh ( J& K ) and flows into Pakistan.

45. The other rivers of this system, viz. Jhelum and Chenab, flow partly though Jammu and Kashmir, while Ravi, Sutlej and Beas flow through Himachal Pradesh and Punjab, before entering Pakistan. The major fishes in Indus are Schizopygopsis stoliczkee , L. gontius , Rita buchanani , Sisor rhabdophorm , Exostoma stolicizkae , Trichogaster sp and Nemacheilus spp.

46. River Jhelum This river has its origin from a spring ( Verinag ) in Kashmir and flows northward receiving large number of tributaries. It flows through the city of Srinagar into the Wularlake , its delta and finally drains into Pakistan . The common fishes found in the river Jhelum include Schizothoraichthys spp , six species of Schizothorax , Diptynchus maculatus , Cyprinus carpio , Labeo dero , Crosscheilus diplochilus , Salmo trutta fario , Glyptosternum reticulatum , Botia birdi and Nemacheilus gracilis and Nemacheilus kashmirensis .

47. River Chenab This river originates in high altitudes in Himachal Pradesh, enters the Jammu and Kashmir at, 1,820 msl and flows for about 290 km in different towns and finally enters Pakistan . The fishes that are common in the river Chenab are Dipthychus maculates and Glyptothorax kashmirensis .

48. River Ravi This river originates from Bara Bang- Dhauladhar range of the Himalayas as two channels, namely Budhil and Tantgari , at an elevation of 4,423 and 4,418 msl .

49. Out of total river length of 725 km, it is 320 km within India, of which 158 km lie within Himachal Pradesh and 162 km within Punjab. The major fishes present in the river are Amblypharyngodon mola , Barilius bendelisis , Carassius carassius , Catla catla , Cirrhina mrigala , C. reba , Cyprinus carpio , Labeo spp , Tor tor , Mastacembelus armatus , Channa spp., Trichogaster fasciatus , Clarias batrachus , Heteropneustes fossilis , Mystus spp., Ompok bimaculatus , O. padba , Rita rita and Wallago attu .

50. River Beas This river takes its origin in the southern slope of Rohtang pass from sources Beas Kund (4,060 msl ) and Beas Rishi (4,350 msl ). It has a catchment area of 12,130 km2 and drains 25,900 km2 of Himachal Pradesh and Punjab.

51. The most common fishes are Xenetodon cansi , Gadusia chapra , Amblypharyngodon mola , Barbus spp , Carassius carassius spp , Catla catla , Chela spp , Cirrhinus mrigala , C. reba , Cyprinus carpio , Labeo spp , Danio devario , Tor tor , Nemacheilus botia , Oxygaster gora , Puntius spp , Rasbora daniconius , Mastacembelus armatus , Channa spp., Trichogaster fasciatus , Clarias batrachus , Heteropneustes fossilis and Notopterus spp.

52. River Sutlej Sutlej, the longest tributary of Indus system, has its source in the Trans-Himalayas at an elevation of 4,630 msl at south-west of Tibetian lakes, Ralkarthal and Mansarovar . Has total length of 1,450 km out of which 740 km lie within India.

53. The most common among them include Wallago attu , Clarias batrachus , Heteropneustes fossilis , Mystus spp , Rita rita , Eutropiichthys vacha , Notopterus notopeterus , N. chitala , Puntius spp , Colisa fasciatus , Esomus danricus and Chela laubuca .

54. East coast river system The East coast river system in Peninsular India is a composite system of rivers. Its main constituents are rivers Mahanadi, Godavari, Krishna and Cauvery. The total combined length is about 6,437 km. This system drains the entire Peninsular India (from east of Western Ghats in the west to Bay of Bengal in the east) and southern parts of Central India (including Chotta Nagpur hill ranges).

55. River Mahanadi River Mahanadi rises from Sihawa hills (near village Pharsia ) in south-west of Raipur district in Chhattisgarh. With a total length of about 857km, in Chhattisgarh, Madhya Pradesh and Odisha, it drains an area of about 141,600 km2. Annual fish landing- 152.37 tonnes / yr

56. Fish and Fisheries of Mahanadi The river mainly harbours the hill stream fishes. The most common fishes are Chela untrahi , Erethistes conta and Arius gagora .

57. River Godavari River Godavari, the largest of Peninsular rivers and the third largest river in India (next to rivers Ganga and Brahmaputra), is about 1,465 km long from its origin near Deolali hills Nasik (Maharashtra) in Northern-Western Ghats to its tidal limits below Rajahmundry (Andhra Pradesh).

58. Fish and Fisheries of Godavari The most common fishes in this river include fishes such as carps ( Labeo fimbriatus , Cirrhinus mrigala , Labeo calbasu , Catla catla ), catfishes ( Mystus seenghala , Mystus aor , Silonia childreni , Wallago attu , Pangasius pangasius , Bagarius bagarius ) and Hilsa ilisha . Of the several carp species, L. fimbriatus is found to dominate and this is followed by C. mrigala . Macrobrachium malcolmsonii (Godavari prawn) is the prawn common in this river. Fishing gears that are commonly employed are gillnets (set gillnet, drift gillnet, drag gillnet, barrier gillnet), seines (shore seine, large seine and drag net) and cast net.

59. River Krishna The Krishna river system has a total length of about 1,280 km from its origin in Mahabaleshwar hills in the Western Ghats, south of Pune (Maharashtra), to its delta on the east coast. Traversing the states of Maharashtra, Karnataka and Andhra Pradesh, it has a catchment area of about 233,229 km2

60. Fish and Fisheries of Krishna The fish species composition is similar to the Godavrai system. The major fishes of the river include carps ( Labeo fimbriatus , Cirrhinus mrigala , Labeo calbasu , Catla catla ), c atfishes ( Mystus seenghala , Mystus aor , Silonia childreni , Wallago attu , Pangasius pangasius , Bagarius bagarius ) and Hilsa ilisha . Fishing gears employed are similar to the Godavrai system.

61. The river Cauvery It is one of the great rivers of India. This river is also called Dakshin Ganga. It originates in the Brahamagiri hills in the Western Ghats range of Karnataka state, and from Karnataka through Tamil Nadu, it empties into the Bay of Bengal. The source of the river is Talakaveri located in the Western Ghats about 5,000 feet (1,500 m) above sea level .. Its basin is estimated to be 27,700 square miles (71,700 km²).

62. The large Mettur dam has been constructed across Cauvery in Tamilnadu . In Tamilnadu , in the Thanjavur delta, the river divides into a northern branch, the Coleroon and a southern branch, the Cauvery proper. The Lower anaicut is across the river, Coleroon and the Upper anaicut and Grand anaicut are across Cauvery proper.

63. Fish and Fisheries of Cauvery Eighty three species of fishes belonging to 23 families have been reported from the Cauvery river. The most common fish species are as below : Carps : Catla catla , Labeo rohita , Cirrhinus mrigala , Cyprinus carpio , Tor putitora , Barbus carnaticus , B. dubius , Labeo kontius , Cirrhinus cirrhosa , Acrossocheilus hexagonolepis , Osteochilus hexagonolepis , Osteochilus brevidorsalis etc . Catfishes : Mystus seengala , M. aor , Wallago attu , Pangasius pangasius , Silonia silondia , Glyptothorax madraspatanum etc.Miscellaneous : Notopterus notopterus , Channa marulius , Osphronemus goramy etc .

64. West coast river system The west coast river system drains the narrow belt of Peninsular India west of Western Ghats. In north it includes the basins of rivers Narmada and Tapti and the drainage of Gujarat. Rivers Narmada and Tapti are the main rivers of this system. All other rivers, arising from Western Ghats are short, though perennial. The total length of rivers of this system is about 3,380 km.

65. River Narmada The largest west flowing river of the country, Narmada, originates from Maikala highlands near Amarkantak in Shahdol district of Madhya Pradesh. Its drainage area is the northern extremity of Deccan plateau. Of its total length of about 1,312 km, it traverses for about 1,077 km in Madhya Pradesh. Total catchment area of river Narmada is about 94,235 km2.

66. Fish and Fisheries of Narmada The fisheries of the river Narmada consists of the following species. Carps: Tor tor , Labeo fimbriatus , L. calbasu , L. bata , Labeo kontius , Cirrhinus mrigala , C. reba , Catla catla , Puntius sarana etc. Catfishes: Mystus seengala , M. aor , M. cavasius , Wallago attu , Rita pavimentata , Ompok bimaculatus etc Miscellaneous : Notopterus notopterus , Channa spp., Mastacembelus spp , minnows etc Fishing gears employed: They include cast net, gill net, long lines etc.

67. River Tapti River Tapti, also called Tapti , is the other westerly flowing river of the Peninsular India. Rising from the Vindhya mountain of the Satpura range, it flows westward through Madhya Pradesh, Maharashtra and Gujarat before joining the Arabian Sea at Dumas near Surat (Gujarat). The total catchment area of this river is about 48,000km2.

68. Fish and Fisheries of Tapti Fishing season commences from September to October and continues till the onset of monsoon. Fishing operations are extensive after Jan - Feb. Cheer fishing also takes place during Nov – Jan with scare line and a composite net made by towing two cast nets. Fishing gears employed are similar to the Narmada rivers sytem .

69. Climate change and fisheries Perceptible changes on a global and regional scale are evident in earth’s climate. In India observed changes include an increase of air temperature, regional monsoon variation, frequent droughts and a regional increase in severe storm incidence in coastal states of India along with indication of Himalayan glacier recession.

70. The impact is being felt in the inland aquatic resources and their fisheries. Analysis of time series data of 30 years from published literature and from current investigations on the River Ganga and water-bodies in its plains indicate increased minimum water temperatures, 1.5˚c in colder stretches of the Ganga and 0.2 to 1.6˚c in the aquaculture farms of the West Bengal in the Gangetic plains.

71. Rainfall has also increased in the post-monsoon months of September-December. The impact is manifested in the breeding failure of the Indian major carps and a consequent decline in fish spawn availability in the river Ganga. Fish production showed distinct change in the last two decades in the middle stretch of river Ganga where the contribution of IMC has decreased from 41.4% to 8.3% and that of miscellaneous and catfish species increased.

72. Climate change in India will put an additional stress on ecological and socio-economic systems that are already facing pressure. Thus the specific climate variables of importance to inland fisheries, viz. enhanced water temperature, extreme events like flood and drought, storms and water stress require specific adaptation actions.

73. Interlinking of rivers The National River Linking Project (NRLP) envisaged transferring water from the surplus river basins to ease the water shortages in western and southern India while mitigating the impacts of recurrent floods in eastern India. The NRPL constitutes two basic components-the links which will connect the Himalayan rivers and those which will connect the peninsular rivers.

74. The project would consist of 30 river links and 3,000 storage structures to transfer 174 km3 of water through a canal network of about 14,900 km. The recent revival of the idea of interlinking of ‘surplus’ basins with ‘deficit’ basins has been the result of work done by the National Water development Agency (NWDA) and bears a conceptual continuity with Dr Rao’s proposal.

75. Components of NRLP The Himalayan component proposes to transfer 33 km3 of water through 16 river links. It has two sub-components: (a) The Ganga and Brahamputra basins to Mahanadi basin (links 11-12); and (b) Eastern Ganga tributaries and Chambal, Sabramati river basins (links 1-10).

76. The Peninsular component proposes to transfer 141 km3 water through 14 river links. It has four sub-components: (a) Mahanadi and Godavari basins to Krishna, Cauvery and Vaigai rivers (links 1-9); (b) West-flowing rivers south of Tapi to north of Mumbai (links 12 and 13) (c) Ken River to Betwa River and Parbati , Kalisindh rivers to Chambal rivers (links 10 and 11); and (d) Some west flowing rivers to the eastern rivers (links 14).

77. Gears The dragnets, gill nets and hooks are commonly used by fishers to catch fish. Dragnets of two types small (less than 300m in length) and large (more than 300m in length) are in use. The fishers use hook and lines in the upper stretch mainly and partly in the middle stretch, whereas traps are in use in some distrcts of Bihar stretch of the river system

78. In some districts of Bihar, and Varanasi, Ghazipur and Balia districts of Uttar Pradesh use of large dragnets of mosquito net clothing with minimal mesh size is common. These gears are highly destructive both to fish stocks and ecosystem as well.

79. In the recent past the use of dragnets, traps, hooks and lines has declined sharply as compared to sixties. At present the availability and use of gill nets had increased manifold in all stretches. Large seines called as Mahajals are generally used in the Ganges. For fishing in small areas “dragnets are best suited .

80. Larger form called as Berjal are extensively used in the Ganges. Berjal are without sinkers and are spreader in the river in a semicircular fashion. For carrying and spreading the net boats are used. The two ends of the net are held by several persons on the shore for dragging the net. Rangoon net with large number of small sized sinkers tied to the foot row is used in the areas with non uniform and uneven bottom .

81. Specific type of nets is used for specific type of fishes. For Hilsa fishing Kona jal or Bhasa gulli having conical pockets are used in West Bengal and Bihar. Katla Jal is used specially tо capture carps and is common in Bihar and Uttar Pradesh. For cat fishes “ Hela Jal ” which is a dip net consisting of two light bamboo poles crossing each other are in practice. In river Narmada a special type of dip net known as “ Khoila Jal ” are used for the capture of grey mullet. 

82. Impacts of dams on riverine fisheries Harmful effects Harmful effects of dams and other structures on the fish populations can be categorized into ( 1) Obstructional ( 2) Ecological

83. Obstructional effects of dams on fisheries If the riverine fishery is sustained by stocks of migrating fishes that become blocked by a dam, the riverine fishery can be severely impacted. If the migrating fishes are anadromous or catadromous species, linked to ocean fisheries, or those of inland seas or large lakes, the negative impacts to these stocks and their associated fisheries can be catastrophic.

84. Major concern throughout Asia is that movements of migratory fishes along river courses will be blocked by dams. Dams also can block the flow of nutrients from ocean environments upstream into riverine environments by preventing anadromous fishes that die after spawning ( eg , Pacific Salmon) from depositing these nutrients via carcass decay in upstream reaches.

85. Ecological effects of dams on fisheries Ecological changes affect both migratory and non-migratory species of fishes. The most obvious effects from placing dams on rivers result from formation of new lentic or semi-lentic environments upstream from the dam, and tailwater environments downstream from the dam. Both environments can be conducive to the establishment and maintenance of fish stocks appropriate for exploitation by fisheries.

86. However, when several dams are constructed on upstream tributaries of a river ecosystem, the cumulative effects of these dams can be that of blocking the flow of nutrients originating from the catchment basin from the lower reaches of the ecosystem, thereby negatively affecting fisheries production in downstream portions of the ecosystem (including estuary and marine environments). Some species shift to new spawning and migration range Anadromous fishes tend to settle down Local stocks of fish form Intra-specific biological differentiation of fish occurs

87. Egg-laying substrata change Spawning grounds inundate Water levels fluctuate Physico -chemical conditions of spawning areas in the upper reaches, marshlands, constituting the spawning and feeding grounds of some important food fishes may disappear. Turbidity and silting pattern change. It may result in the failure of spawning or ineffective spawning of many important fishes.

88. Beneficial effects of dams on fisheries Beneficial reservoir fisheries also exist in drier regions where dams are constructed for agricultural irrigation, and fisheries are secondary considerations. Stocking of exotic species (both in reservoirs and in tailwaters ) can enhance yields, as long as the exotic fishes are environmentally sound and culturally acceptable to the surrounding human population.

89. Dams also can enhance some riverine fisheries, and particularly with respect to tail water fisheries immediately below dams. Fishes can become concentrated below dams as a result of the attractive foraging opportunities there as well as from seasonal congregations of migratory fishes. On a per unit area basis, tailwater fisheries can be better than those of the reservoirs themselves.

90. Impacts of dams on fisheries in India Dams have had negative impact on river fisheries in various systems throughout the region. Sharp declines in catches of Hilsa ilisha were noticed as a result of dams, barrages, weirs and anaicuts on the Hooghly,Godavari , Krishna and Cauvery rivers, and that mahseer Tor putitora and T. tor no longer are found above Nangal and Talwara dams. Fish ways constructed in conjunction with dams are used as fish traps by local fishers.

91. In addition to impacts on hilsa and mahseer stocks and their associated fisheries, formation of reservoirs in India has had negative impact on snow trout ( Schizothorax ), and rohu ( Labeo ) in Himalayan streams, and catadromous eels and freshwater prawns in all major river systems.

92. One of the earliest known impacts to river fisheries in India occurred as a result of construction of Mettur Dam (1935) on the Cauvery River, which formed Stanley Reservoir and completely stopped runs of the Indian shad Tenualosa ilisha . Within the reservoir itself, water level changes, recruitment failures and predation resulted in reduced stocks of Indian major carps.

93. Measures to overcome the negative impacts of dams Bernacsek (1984) provided an excellent summery of design and operational features for dams to address fisheries concerns. He suggested: ( i ) maximum possible crest elevation (ii) discharge structure intakes positioned at highest possible elevation (iii) discharge water into tail waters be sufficiently oxygenated to support aquatic fauna.

94. (iv) annual water level fluctuation in the reservoir to be within the range of 2.5-4.0 m (v) drawdown rate not to exceed 0.6 m/month (vi) downstream discharge to include an annual artificial flood event. Along the stream continuum, dams and their associated upstream reservoirs have downstream effects on riverine environments and, subsequently, diverse influences on downstream fisheries, even beyond the lotic ecosystem. Further, to facilitate the migration of fish during breeding period, fish passes or fish ways are found necessary and successful.

95. Fish passes / Fish ways A fish pass is an inbuilt arrangement in a headwork or barrage or a dam facilitating the upstream migration of fishes to reach their spawning grounds . A fish pass must be attractive, accessible and must afford an easy passage for the fish. In a typical fish pass the water flow is usually fast, invariably shallow and turbulent and the fish find sanctuary behind the projections, ultimately move their head out and will come out the move upstream.

96. Types of Fish passes / Fish ways 1) Natural : In this type of fish passes the approach routes of fish may be strengthened with concrete to the natural rock with the natural rock with the object of concentrating flows previously diffuse, reducing turbulence and deepening pools. 2) The Pool design (Fish ladder) : It consists of a series of pools arranged in a ladder-like manner from downstream to upstream. The flow of water from pool to pool may be over solid obstacles or through passages between obstacles or a combination of two types. Each pool is designed in such a way that it provides adequate resting grounds for the ascending fishes.

97. 3) Deep baffled channel : This is a modified Deniel type of fish way designed for low gradient and is suitable for extreme variations in inflow and water level. Actually, it is a single slot vertical baffle fish way. 4) Simple sluice or inclined chute : The chute is an inclined channel or a sort of waterfall with deep descent. The effective width of the channel is actually much less than the width of sluice and many sharp turns cause cross currents that are very difficult to be counteracted by large fishes.

98. 5) The Deniel design : It is a narrow channel with closely spaced baffles set at an angle with the axis of the channel. In this kind of fish way, the force of fast flowing water is minimized and fishes can negotiate them easily. 6) The Fish lock : It is an arrangement for the regulation of flow of water with the help of mechanical gates. The inflow and outflow can be regulated thus providing fishes with the passage to move either way. 7) Other types include fish lifts, dished channel, submerged orifice and roughened channel.

99. Fish passes are key elements for the restoration of free passage for fish and other aquatic species in rivers. The few fish passes built in India are on the Mahanadi barrage, Naraj barrage on river Mahanadi, the Hathnikund barrage on river Yamuna and Farakka barrage on river Ganga.

100. The fish passes in the barrages on river Mahanadi are of the Denil type and in Farakka barrage on river Ganga it is Fish lock. These passes were constructed to take care of the migratory requirement of the Indian major carps, Macrobrachium rosenbergi and Tenualosa ilisha . Unfortunately these requirements has been partially fulfilled. Most of these structures had some drawbacks.

101. This can be overcome by intensive research on the hydraulic design offish passes for structures of varying heights and on migration behavior of the migratory fishes of India CIFRI is conducting research on this important aspect and has designed pool type fish passes for some upcoming dams in the rivers of north eastern India.

102. FISH STOCK CONSERVATION To initiate awareness for the conservation of biodiversity, revival of commercially viable biomass and protection of the habitat, programme should be taken up in identified areas. Conservation and sustainable exploitation for river fish taken in one state need to be complemented by neighbouring states up or downstream of the rivers following globally agreed principles of responsible fishing.

103. Indiscriminate fishing of juveniles from secluded pools of water created along the banks of the rivers after the flood recedes has been a major cause of depletion of commercially important fish stocks in the rivers. Therefore, these broodstock pools may be protected by declaring them as fish breeding parks/sanctuaries.

104. Certain identified strategic but manageable high – altitude streams/lakes may be adopted under a conservation of biodiversity programme through a ban on fishing, protection of habitat through punitive orders and enhancement of natural population with ranching of certain species with seed of mahseer , snow-trout and other vulnerable species.

105. The existing rules and regulations under the Indian Fisheries Act (1897) have provision to control and monitor the use of gear, mesh size as well as observance of fishing on closed seasons. For effective implementation of regulations, the following measures may be considered. Mesh size regulation may be monitored by inspecting landing centers for fish size in particular seasons and parties operating the river stretch be made responsible for effective operation.

106. River stretches to be leased/auctioned may be done on state level than on district level to minimize fishing pressure per unit length of the river by the lessee Lease period should have a flexible component with possibility to extend the period depending upon the effective implementation of conservation measures by the lessee.

107. Rehabilitation of river fisheries The Food and Agriculture Organization (FAO) has published The Technical Guidelines for Responsible Inland W ater Fisheries in which it has summarized the main processes that need to be undertaken in the planning, execution and follow up of any rehabilitation project.

108. Prior activities Establish database of benchmark rivers and lakes associated and typical fish assemblages. Assess condition in target river Identify disrupted ecosystem processes Prioritize target reaches and possible rehabilitation actions

109. Define need for and objective of rehabilitation – carry out overall feasibility study. Assess water quality problems Define general scope and scale of project Policy, legal and financial issues Clarify legal situation with regard to various options for rehabilitation

110. Follow – up Monitor effectiveness of measures adopted. Modify to improve any deficiencies observed. Restore channel diversity and vegetation. Conserve or rehabilitate lateral connectivity. Carry out routine maintenance of fish – passes.