Kerala is a small state, tucked away between the Western Ghats and the Arabian Sea, in the southwestern corner of India. The land is known for its picturesque landscapes and highly educated people. With a very high quality of life index and literacy, the State is one of the most densely populated in India. Geographically, Kerala is unique and its climate is often described as pseudo-tropic. The State is endowed with liberal rainfall and all round lush vegetation. Some of the last remnants of the tropical rain forests of India are situated here. It is the privilege of Kerala to usher in the southwest monsoon to the country. The tall, well-wooded hills of Western Ghats precipitate a bountiful rainfall that flows down to the Arabian sea through 41 small, west-flowing drainages. These rivers, the longest being Bharatapuzha, 267 km, carry an annual discharge of 72 673 million m3 per year, which is much higher than the quantum of water being carried by large rivers like Cauvery, Krishna and Tapti.
Unlike its big neighbour, Tamil Nadu, Kerala does not have a history of ancient irrigation reservoirs to boast; the traditional practice of agriculture depending mostly on the local rainfall. Storage of river water for irrigation and power generation is a relatively modern concept in Kerala, where most of the dams are constructed after independence. There are 30 reservoirs in the State, spread over 29 635 ha, in the districts of Palakkad, Trissur, Thiruvanathapuram, Pathanamthitta, Kollam, Kannur and Idukki. Most of them are logistically suitable for fish yield optimisation, primarily due to their manageable size. Twenty-one of them are below 1 000 ha in area and among the rest, only the Idukki reservoir is over 5 000 ha (Fig. 3.1). Bharathapuzha is extensively dammed for irrigation purposes in Palakkad district, resulting in nine impoundments (11 351 ha). Similarly, Periyar river is tamed for hydro-electric power generation in the undulated terrains of Idukki district, creating nine reservoirs (6 633 ha; Table 3.1). The total waterspread areas under 21 small, 8 medium and 1 large reservoirs are 7 975, 15 500 and 6 160 ha respectively (Table 3.2).
Kerala is the foremost fish producing state in India. However, 97% of the State's production is from the marine sector and out of the inland fish production of 3%, only 0.3% comes from the reservoirs (Das et al., 1993). Despite the existence of many small reservoirs in the State, no serious attempts have been made, till recently, to develop them on scientific lines for fish yield optimisation. This is primarily due to the inadequate attention received by the inland fisheries sector during the early years of the State's planned development, as the Keralites have a marked bias in favour of marine fish. During the last few decades, due to improved facilities for processing, storage and transport, marine fish has become available to consumers all over the State, resulting in a shortage. Thus, the people have turned towards the inland fish and they even developed a taste for it. Catla, rohu, mrigal and even common carp are no longer at a discount, in comparison to sardines and mackerels. Now, the State has recognised the importance of inland fisheries and freshwater aquaculture. However, a perusal of literature indicates that no major initiative has been taken to create a database on the ecosystem functions and production potential of reservoirs in the State. Very little information is available on their water quality and biotic communities.
|No.||Name of Reservoir||Area (ha)||District||Location||River|
|1.||Malampuzha||2313||Palakkad||10° 40'||76° 39'||Bharatapuzha|
|2.||Mangalam||393||do||10° 31'||76° 58'||do|
|3.||Meenkara||259||do||10° 38'||76° 48'||do|
|4.||Chulliar||159||do||10° 36'||76° 46'||do|
|5.||Pothundi||363||do||10° 07'||76° 10'||do|
|10.||Peechi||1263||Trissur||10° 30'||76° 15'||Karuvannoor|
|11.||Vazhani||255||do||10° 40'||76° 15'||Keecheri|
|12.||Sholayar||870||do||10° 17'||76° 45'||Chalakkudy|
|14.||Neyyar||1500||Thiruvananthapuram||08° 32'||77° 08'||Neyyar|
|15.||Peppara||582||do||08° 07'||76° 40'||Vamanapuram|
|16.||Aruvikkara||258||do||08° 28'||77° 58'||Karamana|
|17.||Pamba||570||Pathanam-||09° 20'||76° 53'||Pamba|
|19.||Parappar||2590||Kollam||09° 57'||77° 4'20"||Kallada|
|20.||Kuttiadi||1052||Kozhikode||11° 36'||75° 49'27"||Kuttiadi|
|22.||Idukki||6160||Idukki||09° 48'||76° 53'||Periyar|
|23.||Ponmudi||260||do||09° 55'||77° 05'||do|
|24.||Anayirankal||433||do||10° 0'||77° 0'||do|
|26.||Mattupatti||324||do||10° 05'||77° 05'||do|
|30.||Periyar lake||2890||do||10° 10'||76° 15'||do|
Idukki, the prestigeous hydro-electric power project of Kerala consists of three dams, viz., the Idukki double arch dam across the river Periyar, the adjacent Cheruthoni concrete gravity dam and the big masonry Kulamavu dam, located 30 km upstream of Idukki on the left bank. The 6 160 ha reservoir is spread on the beds of two rivers, viz., Periyar and Cheruthoni. Idukki reservoir receives water from the catchments of a number of minor streams. Total catchment area is estimated at 649.3 km2 and gross storage capacity. 1 996.3 million m3. At FRL, the reservoir attains an elevation of 732.62 m with average depth ranging from 50 to 80 m. The calculated mean depth (volume/area) is 32 m.
Khatri (1985) reports the physico-chemical profile of water in Idukki reservoir. The water, although warm (21.8 °C to 26.3 °C) and clean (transparency 55 to 540 cm), is poor in nutrients. Being a deep basin reservoir, a substantial part of the storage is always held up as dead storage. Among nutrients, phosphate is totally absent and nitrates and silicates are in very low concentrations (Table 3.3). Nutrients, especially phosphates, seem to be the limiting factor for primary productivity in the reservoir. Whatever nitrates and silicates are available are locked up in the deep aphotic layers.
|Air temperature (°C)||21.2–29.8|
|Water temperature (°C)||21.8–26.3|
|Free CO2 (mg l-1)||nil–70.0|
|Bicarbonates (mg l-1)||7–42|
|Dissolved oxygen (mg l-1)||1.2–9.8|
|Silica (μg l-1)||95–199|
|Phosphate (μg l-1)||nil|
|Nitrate (μg l-1)||1.7–18.7|
After Khatri, 1985
Standing crop of phyto and zooplankton in Idukki is reported to be extremely poor with the overwhelming presence of the oligotrophic species, viz., Ankistrodesmus sp. and Cosmarium sp. Cyanophyceae are scanty (Khatri, 1987a) and believed to be of allochthonous origin. The reservoir has an equally poor zooplankton community (Khatri, 1988). Seventeen species of fishes, including two exotics are reported from Idukki (Gopinath and Jayakrishnan, 1984). Presently, there is no organised fishing in the reservoir. A few local people inhabiting along the reservoir margin are engaged in improvised fishing practices, using local fishing implements such as thandadivala or kethevala, which are crude gill nets with mesh size varying from 26 to 180 mm. Gopinath and Jayakrishnan (1984) recorded fish catch of 705.97 kg during 11 months from September 1982 to July 1983. Six species that figured in the commercial landings were Cyprinus carpio, Cirrhinus cirrhosa, Channa gachua, Mastacembelus guetheri, Tor khudree and Oreochromis mossambicus (Fig. 3.3). Ompok bimaculatus and Heteropneustes fossilis were also present in small quantities. Seventeen species of fishes and eleven birds have been recorded from Idukki (Table 3.4 and 3.5). Nair (1988) considers Idukki to be passing through a trophic depression, as evidenced by low rate of colonisation by fish food biotic communities and the retarded growth rate of Orechromis mossambicus.
Figure 3.2. Idukki reservoir, Kerala
|1. R. daniconius|
|2. B. bendelisis|
|3. C. carpio|
|4. P. melanampyx|
|5. P. bovianicus|
|6. T. khudree|
|7. C. cirrhosa|
|8. G. lamta|
|9. N. denisonii|
|10. N. scaturigina|
|11. N. rupicola|
|12. O. bimaculatus|
|13. H. fossilis|
|14. A. lineatus|
|15. C. gachua|
|16 O. mossambicus|
|17. M. guentheri|
Source: Gopinath and Jayachandran, 1984
Figure 3.3. Catch by weight (kg) for the major fish species (Idukki reservoir after Gopinathan and Jayakrishnan, 1984
|Common name||Zoological name|
|Little cormorant||Phalacrocorax niger|
|Cattle egret||Bubulcus ibis|
|Little egret||Egretta garzetta|
|Common sand piper||Tringa hipoleucos|
|Night heron||Nycticorax nycticorax|
|Pond heron||Ardeola grayu|
|White-breasted kingfisher||Halcyon smyrtensis|
|Small blue kingfisher||Alcedo atthis|
|Pied kingfisher||Ceryle rudis|
Source: Gopinath and Jayachandran, 1984
The 2 590 ha Parappar reservoir was commissioned in 1987 on the Kallada river in Kollam district at 9° 57' N, 77° 4' E. The Project comprises two hydraulic structures, viz., the Thenmala dam and the Ottackal weir. The dam Thenmala is built across Kallada, just below the confluence of its three small tributaries, the Kulathupuzha, the Chendurni and the Kalthurthy, forming the Parappar reservoir at an elevation of 1 225 m above MSL. The outflowing river Kallada joins the Ashtamudi lagoon and estuary (Fig. 3.4).
Kallada river, downstream the Parappar reservoir, receives industrial effluents from the Punalur Paper Mills, causing concern among the environmentalists. The reservoir, however, is reported to be free from pollution. A pre-impoundment survey by Nair (1986) throws light on the environmental characteristics of river stretch. Sahib and Aziz (1989) examined the water quality above and below the dam, with special emphasis on the pollution load and water quality. They found an increase in water temperature and transparency in the impounded area during monsoon and post-monsoon seasons, compared to the pre-impoundment period, with a corresponding drop in hardness and dissolved oxygen levels. The reservoir water was neutral in reaction with low levels of nitrates and phosphates (Table 3.6). No appreciable level of vertical gradient was observed in respect of temperature and chemical parameters through seasons.
Neyyar is an irrigation reservoir created on the Neyyar river at lat. 8° 32' N and long. 77° 08' E, about 30 km south-east of Thiruvananthapuram at the foot of the holy hill, Agasthyakudam. Commissioned in 1959, the reservoir has a waterspread of 1 500 ha and receives catchment from 140 km2. Neyyar reservoir, apart from meeting the irrigation needs of Thiruvananthapuram district, recharges the Aruvikkara reservoir to maintain uninterrupted water supply to the city of Thiruvananthapuram and its suburbs (Fig. 3.5).
Harikrishnan and Azis (1989), who made an indepth study of the reservoir, found it ideal for fisheries development. The water temperature, which varied from 28.0 to 32.0 °C during different seasons, did not show any vertical stratification. Range in values of other physico–chemical parameters is given in Table 3.7.
Figure 3.4. Parappar reservoir, Kerala
Figure 3.5. Neyyar reservoir, Kerala
|Water temperature (°C)||27.5||26.7||28.4|
|Total hardness (mg 1-1)||10.5||5.5||8.7|
|Dissolved oxygen (mg 1-1)||3.4||5.5||5.2|
|Nitrite (μg 1-1)||4.7||0.9||0.9|
|Nitrate (μg 1-1)||-||-||0.9|
|Phosphates (μg 1-1)||27.49||-||-|
|Silicate (μg 1-1)||133.8||151.1||175.3|
(After Sahib and Azis. 1989)
|Parameter||Range in values|
|Station I||Station II|
|Water temperature (°C)||28.0–32.0||28.5–32.0|
|Dissolved oxygen (mg 1-1)||5.9–9.6||6.3–9.7|
|Dissolved carbon dioxide (mg 1-1)||1.1–6.6||1.1–4.4|
|Total hardness (mg 1-1)||6.0–20.0||8.0–24.0|
|Nitrite nitrogen (μg 1-1)||1.23–12.25||1.23–7.35|
|Nitrate nitrogen (μg 1-1)||5.28–211.2||7.92–142.0|
|Phosphate phosphorus (μg 1-1)||0–16.64||0–8.32|
|Silicate-silica (μg 1-1)||2.08–4.48||2.24–4.16|
(After Harikrishnan and Aziz, 1989)
Kuttiadi river originates from Narikotta ranges in the Western Ghats, at an elevation of 1 220 m above MSL and joins the Arabian Sea at Kottackal, after traversing 74 km across the State. The straight gravity masonry dam, situated at Peruvannamuzhi, is 173 m long and 36 m in height. At the dam site, the river receives catchment from 1 095 km2. Gross and net capacity of the reservoir are 121.2 and 113.9 million m3. Mean annual rainfall at the watershed is estimated at 3 445 to 7 760 mm. The irrigation reservoir serves a total cultivable command area of 25 490 ha and a total irrigated area of 14 566 ha. Kunhi (1990) reports thermal stratification in the reservoir during post-monsoon months, accompanied by a cinograde oxygen distribution. Reporting very high levels of phosphorus in the water phase, the author places the lake under the eutrophic category.
Total fish production from the reservoirs of Kerala is not known. Although 17 reservoirs in the State are under regular stocking by the State Government, latest (1992–93) annual fish production figures are available only in respect of 9 reservoirs (Table 3.8). Normally, the data on reservoir fish production are based on sales figures from co-operative societies, which do not account for other important sources and uses of fish produced, such as illegal removal of fish by poachers, non-marketed production (subsistence consumption) and illegally marketed fish (Das et al., 1993). Present total fish supply from the five reservoirs (Malampuzha, Peechi, Pothundi, Vazhani, and Chulliar) covered under the Indo-German Reservoir Fisheries Development Project is estimated at 384 t yr1, out of which 336 t (88%) is marketed. This is against the official figure of 81.6 t. The Project has estimated an annual potential fish supply of 650 t from the five reservoirs and 1 700 t from all reservoirs of Kerala.
|Reservoir||Area (ha)||Total fish landings (kg)||yield (kg ha-1)|
|1. Peechi||1 263||5 734||4.5|
|2. Vazhani||255||6 985||27.4|
|3. Malampuzha||2 313||11 540||5.0|
|4. Mangalam||393||17 494||44.5|
|5. Meenkara||259||17 776||68.6|
|6. Chulliar||159||50 334||316.6|
|7. Pothundi||363||7 057||19.4|
|8. Walayar||259||4 700||18.1|
|9. Kanjirampuzha||512||13 406||26.2|
Source: Satet Fisheries Department
During the last 13 years, the yield from the managed reservoirs registered an impressive four-fold (from 34.9 t in 1978–79 to 147.7 t in 1991–92) increase, though the present yield is less than 5 kg ha-1, i.e., a third of the national average, when all the reservoirs are taken into consideration (Table 3.9).
|Total yield (t)||34.90||35.40||79.50||91.60||118.20||147.70||135.03|
|Average yield from managed reservoirs (kg ha-1 year-1)||6.60||6.70||15.10||17.50||20.40||25.50||23.38|
|Average yield from total reservoir area (kg ha-1 year1)||1.20||1.20||2.70||3.10||4.00||5.00||-|
Hydel reservoirs created in the hilly regions generally have deep basins and they portray oligotrophic tendencies, compared to those in the plains which are in transient phases of eutrophication. The irrigation reservoirs of the midland are shallow and spread over the rich alluvial soils. Bountiful sunlight, high temperature regime and nutrients from allochthonous sources make these reservoirs conducive to high primary productivity. Neyyar reservoir in Thiruvananthapuram District has high nutrient loading, in terms of nitrate, phosphate and silicate, indicating eutrophication. Similar nutrient status is reported for Aruvikkara reservoir in Thiruvananthapuram and Parappar reservoir in the Kollam District. Natural populations of fish recorded from Neyyar, Aruvikkara, Kallada and Peppara reservoirs have Puntius sarana, P. filamentosus, Labeo spp, and T. khudree. Among predators, catfishes Wallago attu and Mystus vittatus and the murrels are present.
Development of reservoir fisheries in Kerala on scientific lines is yet to pick up momentum. The State Government initiated steps to develop the reservoir fisheries, way back in 1951, through a three-pronged strategy comprising large-scale production of major carp seed, stocking of carps and creation of breeding and rearing facilities at the reservoir sites. Even though breeding experiments commenced at Malampuzha in 1962, encouraging results were obtained only in the year 1967. Annual seed production in the State rose from 3 million in the 1970s (Nair, 1973) to 14 million in the late 1980s (Sidhardhan and Nair, 1988). Fish farms have been constructed in eight reservoirs for raising stocking material. Available details on six of them are given in Table 3.10.
The first reservoir to be stocked with major carps in the State was Malampuzha, where the fish seed obtained from Tamil Nadu and West Bengal were introduced in 1951. During the 22 years from 1951 to 1972, 2.553 million seed was stocked at an annual rate of 52 ha-1. By 1972, 12 other reservoirs in the State were also stocked at densities ranging from 35 to 805 ha-1 (Table 3.11). The stocking rate in the state over the years is considered to be very inadequate (Nair, 1973; Mathew and Mohan, 1990).
|Reservoir||Nursery area (ha)||Ponds (No.)||Rearing area (ha)||Ponds (No.)||Stocking area (ha)||Ponds (No.)|
*Data not available
(After Venugopal, 1993)
Recent advances in fingerling production
Recently, an advisory mission, under the framework of Indo-German Reservoir Fisheries Development Project has examined the feasibility of organising alternate ways of producing stocking material, using low-cost and easy to manage systems (Rajts, 1993). The emphasis was on a decentralised fry/fingerlings production through target group organisations, as opposed to the present centralised and government services. The project envisaged a fingerling production system operated through fishermen under a cooperative fold, thereby contributing fundamentally to self-sustained culture-based reservoir fisheries development. The proposed production units to be set up in the five reservoirs under the Project, viz., Malampuzha, Peechi, Pothundi, Vazhani, and Chulliar comprise broodfish stock, mini-hatchery and rearing components, in addition to the pens to be erected in the reservoir margin and the off-shore floating cages.
A total incubator volume of 4.0 m3, 1.79 ha of pond area, and 7 ha of pen enclosures are involved in the operation, with an estimated production potential of 40 million hatchlings (Indian major carp, common carp and tilapia). However, an economic evaluation, based on cost and return estimates, made by the project (Schack, 1993) did not consider the pond and pen culture experiments at Pothundy and Malampuzha as viable investment packages. In both cases, the internal rates of return (IRR), calculated over a period of 10 years, was found to be below the loan interest rates charged by the banks. While pointing out the low recapture rates of Indian major carps in many reservoirs, the study strongly advocated the need for evolving alternatives with still lower-cost production techniques.
|Sl. No.||Reservoir||Period||No. of finger-ling stocked (million)||Stocking rate (no. ha-1 yr-1)||Reference|
|1987–88||2.870||1 297||Mathew and Mohan,1990|
|1987–88||0.200||784||Mathew and Mohan, 1990|
Recent advances in fisheries management
Recently, 14 reservoirs in the State, having a waterspread of 17 411 ha, have been identified under a fisheries development scheme. However, stocking and management of even these reservoirs are not up to the desired level. In 1987–88, only 11 reservoirs with a total waterspread of 9 641 ha had been stocked (Table 3.11). Selection of species for stocking seems to be guided more by expediency rather than ecosystem considerations (Table 3.12). During the initial years, a substantial percentage of the seed stocked belonged to the slow growing Labeo fimbriatus, which was later replaced with the major carps. The common carp also found a place among them, though in limited quantities. Criteria for stocking depended entirely on availability of seed, or more precisely, the available seed was distributed among reservoirs in an arbitrary manner. The size of stocking material was invariably small (20 to 40 mm) and the stock was left at the mercy of nature and the predators. Notwithstanding all the shortcomings mentioned above, the stocking did have some positive impact on the fish production in many reservoirs.
Studies on fish population dynamics in Malampuzha reservoir
Under the Indo-German Reservoir Fisheries Development Project, considerable effort has been made by Taege et al. (1993) towards continuous evaluation of stock composition and annual stock assessment in Malampuzha reservoir. Taking into account the complexities arising out of the unstable hydrological, ichthyological, ecological and socio-economic conditions, they suggested continuous revision management decisions on an annual basis.
|Reservoir||Area||No. of seed stocked|
|Catla||Rohu||Mrigal||Labeo fimbriatus||Common carp||Total|
|Malampuzha||2 213||9 525||17 700||357 630||254 335||318 492||957 682|
|Meenkara||259||-||-||4,425||228 000||72 000||304 425|
|Mangalam||393||97 700||97 150||150 400||50 000||-||350 250|
|Pothundy||363||99 500||71 295||79 205||50 000||-||300 000|
|Walayar||259||202 950||835||2 008||462||9 200||215 525|
|Peechi||1 263||77 464||276 735||30 475||39 630||-||424 304|
|Peppara||582||3 000||-||5 000||38 950||8 000||54 950|
|Kanjirampuzha||512||8 000||20 725||155 360||147 000||25 000||395 585|
|Kuttiadi||1 052||66 600||420 000||198 000||271 000||-||955 000|
|Total||7 055||564 735||1004 440||982 573||879 377||432 692||4 002 721|
After Methew and Mohan, 1990)
Fishery resources of Malampuzha reservoir comprise indigenous species and tilapia, that multiply in the reservoir, constituting about 75% of the present yield, and Indian major carps making up the rest. At least three generations of tilapia were reflected in the catch, among which the youngest (99.08 g) was considered as underweight and uneconomical. The pearlspot, Etroplus suratensis was reported to be present in two generations. Pearlspot, along with the exotic member of Cichlidae-Oreochromis mossambicus, registered some decline in recent years, with a simultaneous increase in catches of Puntius spp. suggesting biological imbalance. Puntius sarana was represented by 3 to 4 generations, of which the youngest was considered undersized. Gonoproktopterus curmuca, Parambassis thomassi, and Ompok bimaculatus appeared in only single size groups. Catla and Cyprinus carpio caught during November to April were dominated by undersized individuals. A large population of predatory species, Xenentodon cancila was a cause for concern.
The management strategy evolved by the Indo-German Reservoir Fisheries Development Project comprises:
stocking measures and stock enhancement programmes
self-reliance on fingerling supply of Cooperative Society
diversification of the abundant tilapia stocks,
introduction of strict regulations on mesh sizes of fishing gear
continuous evaluation of stock composition and annual stock assessment, and
annually adjusted management strategies.
Impact of stocking on fish yield rate
The low productivity in most of the reservoirs can be easily attributed to undesirable species mix. A perusal of catch composition in 9 reservoirs reveals that in most cases, the fast-growing species do not get the desired level of representation (Table 3.13). Among Indian major carps, only catla made some impact in Mangalam, Meenkara, and Peechi. Tilapia forms a major component of the catch in many of the reservoirs. Taking all the reservoirs into consideration, out of 79 454 kg of fish, the shares of catla and tilapia were nearly 25 000 kg each.
Sustained stocking had the desired effect in altering the catch structure in favour of major carps in some of the lakes. In Chulliar reservoir, the percentage of major carps varied from 0.2 to 5.5% of the total production during 1969 to 1987 and it went up to 11.5 in 1988–90 (Jhingran, 1991). A similar picture emerges in Meenkara, where percentage composition of catla, rohu and mrigal touched 35.70% during 1988 to 1990 from an abysmal 1.02% till 1983. In Peechi, catla (57.3%), mrigal (9.6%) and rohu (4.8%) together formed 71.6% in 1989–90, compared to 2% in 1966–67. In Malampuzha, the Indian major carps have established a firm foothold. Specimens of Catla catla weighing 16 to 17 kg are a common sight. Similarly L. rohita grows to 4.5 kg and measuring 1 170 mm in length. However, the Indian major carps never exceeded 19.9% of the total catch. Stocking rate and fish yield in respect of four reservoirs are depicted in Tables 3.14 to 3.17.
Chulliar and Vazhani reservoirs registered an impressive increase in yields during 1988 to 1993 on account of the new stocking policy, which gave emphasis on the size and number of the seed stocked. In Chulliyar, yield has increased from 49.10 kg ha-1 yr1 in 1988–89 to 275.50 kg ha-1 in 1991–92. In Vazhani, the corresponding figures were 2.30 and 48.60 kg ha-1 yr-1 respectively.
Oreochromis mossambicus is ubiquitous in the inland waters of Kerala. After its introduction in the State in 1952, this exotic fish has found its way into the household ponds, temple tanks and reservoirs all over the State. Almost all reservoirs in Palakkad and Trissur were stocked with tilapia by the late 1950s and early 1960s (Venugopal, 1993). Employing tilapia for filling the vacant niches in reservoirs is a subject of polemics. The main controversy regarding tilapia is its habit of early maturing and stunted growth. Nevertheless, experience of Kerala reservoirs shows that the fish adapt well in the reservoir ecosystem and thrive on a variety of food items.
|Year||Stocking (no. ha-1 yr-1)||Yield (kg ha-1 yr-1)|
|Year||Seed stocking (no. ha-1 yr-1)||Yield (kg ha-1 yr-1)|
|Year||Seed stocking (no. ha-1 yr-1)||Yield (kg ha-1 yr-1)|
|Year||Seed stocking (no. ha-1 yr-1)||Yield (kg ha-1 yr-1)|
Tilapia contributed significantly to the catch of Chulliar (27.90%) even in 1988–90. In Meenkara, the percentage of tilapia remained high (36.57%) throughout the period of 1966 to 1990. In Malampuzha, where the fish was first introduced in 1956, it is firmly established and forms 31% of the catch since 1986. Individual fish in this reservoir attain an average weight of 2.5 kg, allaying all fears of stunted growth. Tilapia is, in fact, relegating the indigenous species into unimportant positions.
Craft and Gear
A cursory look at the available information on craft and gear indicates that very little thought has been given while organising the fishing effort in reservoirs as an input for development. Quantum of fishing efforts employed in the reservoirs is much below the optimum level, probably with the sole exception of Chulliar. Details of craft and gear in five reservoirs are given in Table 3.18. Small meshed gill nets are operated in the reservoirs without any check, leading to exploitation of undersized fishes. Catching fishes at uneconomic sizes brings pressure on populations and affects the yield considerably.
Fishing in the reservoirs of Kerala was done directly by the staff of the Department of Fisheries until the late 1980s. Later, the cooperative societies were established at the initiative of the Government at all reservoirs. Five cooperative societies operating in Malampuzha, Chulliar, Pothundi, Vazhani and Peechi reservoirs together have a total membership of 1428, belonging to 290 Scheduled Caste and Scheduled Tribe families. Members of these societies are organised into small groups, who go for fishing on selected days according to a roster for avoiding conflicts. However, all members of the society are not keen to fish due to economic and social compulsions.
Drewes (1993), after a critical examination of the scope and issues involved in the organisation and management of reservoir fisheries cooperatives in Kerala, concluded that they were not economically viable, both either as fish production or fish marketing bodies. Nevertheless, he expressed the opinion that they could be transformed into effective instruments for accelerating the socio-economic development, with necessary policy changes at Government level. The policy interventions suggested include:
Cancellation of the royalty to the Government, which amounts to 25% of the cooperative's gross income.
Utilization of the 25% royalty by the cooperative as operating capital (nets, boats, fingerlings)
Discontinuation of government subsidies to meet the cooperative's operating cost (fingerlings, nets, boats, etc.). This will allow a more self-reliant management and avoid outside interference.
Cancellation of the fixed fish sale prices which are about 75% below the prevailing wholesale market prices. This will result in higher income of fishermen/members of the cooperative and increased gross returns of the cooperative to meet operating costs.
Introduction of fish auctioning by the cooperatives. This will ensure that a maximum possible price is realized by the cooperative.
Re–establishing the fishermen/members' share of their cooperative's gross income at a rate which will safeguard an increased income of members and leave the cooperative with sufficient capital to meet its operating cost.
In case of the Pothundy Cooperative, the members' share may be established at 40% of the cooperative's gross income, leaving 60% for the cooperative to purchase fingerlings, boats and nets. The sharing system for the other cooperatives has to be worked out.
|Malampuzha||3 country crafts with outboard engine||3", 8" and 10" mesh gill net; 20 kg/group|
|Peechi||4 country boats and 2 FRP boats||Up to 18" mesh gill nets|
|Chulliar||8 coracles||4", 12" and 15" mesh gill nets; 8 piece/group|
|Pothundi||7 coracles||2", 4", 6" and 8" mesh gill net; 4 kg/group|
|Vazhani||4country crafts||4", 8" and 12" mesh gill nets.|
Source: Interim Report, Indo-German Collaborative Project on Reservoirs in Kerala, 1993
Das et al. (1993) delved deep into the fish marketing and allied activities in five reservoirs. Demand for fish is always high in Kerala and there is a substantial production gap for all types of fishes. This shortfall is expected to become more pronounced in future as marine fisheries are almost fully exploited. This gap could be filled, at least partially, by increased production from reservoirs. There is a market demand for reservoir fish production of at least 700 t in Palakkad and Trissur district and 1 700 t in Kerala as a whole (Das et al., 1993). Margins in reservoir fish production and marketing are reasonable, when compared to marketing of other commodities (rice, beef), except for cooperatives, some of which are in the red (e.g. Malampuzha). Total marketing margin range between 30 to 38%, while wholesale and retail margins are estimated at 21%, and 15 to 38% respectively. Share of producer price in final consumer price is 52 to 59%.
For most fishermen, fishing is not their only occupation. A study made by the Indo-German Reservoir Fisheries Development Project showed that at least in three reservoirs the fishermen earned as much or more from the non-fishing activities (Table 3.19). This suggests the absence of gainful employment opportunities for all members at the present level of fish yield. Nevertheless, Pothundy portrays a brighter picture, where the individual fisherman earn Rs. 14 380 annually from fishing, against Rs. 2 167 from other sources. According to the present arrangement, fishermen get 50% of the sale proceeds and the remainder is shared equally by the cooperative society and the Government.
|Annual income (Rs.) per person from|
|Reservoirs||Fishing||Non-fishing activity||Benefit from fishing|
|Malampuzha||3 638||2 900||+738|
|Chulliar||6 841||4 272||+2 750|
|Pothundy||14 380||2 167||+12 213|
|Vazhani||3 537||811||+2 726|
|Peechi||4 845||5 299||-454|
Source: Interim Report, Indo-German Collaborative Project on Reservoir Fisheries in Kerala.
Among the 290 households in five cooperatives surveyed by Iyer et al. (1993), 73% were nuclear households and 27% were joint families, with an average household size of 5 persons. The average income of a fisherman was about Rs. 12 000 a year i.e., slightly above the poverty line established by Government (Rs. 11 500 a year). Capital outlay of household was described as alarming. Almost all fishermen were indebted through loans from banks and other financing agencies; the average outstanding loan amounting to 25% of a yearly household income. Living conditions of fishermen were equally precarious. Almost 90% of houses were classified as kuccha houses i.e., makeshift or semi-permanent, against 20% for the State as a whole.
Causes of low yield from reservoirs
Factors contributing to the low yield rates from reservoirs of Kerala can be summarised as follows:
Underutilization of resource : Only 9 out of the 30 reservoirs in the State are commercially exploited. This accounts for only 20% of the total reservoir area.
Multiple ownership : The State Electricity Board controls the reservoirs under the hydro-electric projects, which cover more than half of the total area and those situated in the reserve forests are under the jurisdiction of the Forest Department. Fisheries Department has access only to a few irrigation reservoirs. This multiplicity of ownership comes in the way of implementing development plans.
Lack of scientific database: None of the reservoirs in the State has been subjected to thorough scientific investigation and as a result, a deep insight into the eco-dynamics of the ecosystem is lacking. Kerala reservoirs are situated in unique geo-climatic conditions and there is a need to study the environment and the dynamics of biotic communities. A few reservoirs, representing various morpho-edaphic groups, should be studied in detail and the data thus generated need to be used as an input for drawing up management plans.
Inadequate stocking: Most of the man-made lakes in the State, belonging to the category of small reservoirs, are ideally suited for the system of continuous stocking and harvesting. The success of management in such cases essentially centre round an imaginative stocking and harvesting schedule. This calls for creation of adequate nursery facilities to meet the demands. A viable, cost-effective nursery rearing practice for meeting the huge demands from the reservoir sector is yet to be developed.
Selection of species : Selection of candidate species for stocking and determination of species-mix and density have to be made after due consideration of the location-specific information on the trophic status. The practice of stocking undersized fish seed (<100mm) is undesirable.
Lack of manpower development : Upgrading of skill among the operators, creation of awareness about norms of conservation and sustainable yield are essential pre-requisites for motivating people to continue in their profession.
|Year of sealing||1973||1987||1959|
|Area (ha) at FRL||6 160||2 590||1 500|
|Volume (m m3)||1 996||524||106|
|Catchment area (km2)||649||-||140|
|Elevation (m)||732.6||1 225||84.7|
|Maximum discharge (m3sec-1)||8 000||2 832||7.10|
|Total hardness (mg-1||-||5.5–10.5||6–24|