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Study on Phytoplankton, Zooplankton and Ichthyo Fauna of Motia Lake

Sarita Kumari, Jawed Ahmed Khan and Mahender Singh Thakur*

1Department of Zoology, Saifia Science College, Bhopal, Madhya Pradesh, India

2Department of Biosciences, Centre for Environment Studies, Himachal Pradesh University, Shimla-171005, India

*Corresponding Author:
Mahender Singh Thakur
Department of Biosciences, Centre for Environment Studies
Himachal Pradesh University, Shimla-171005, India
Tel: +911772830946
E-mail: drmahender74@gmail.com

Received date: 12/11/2018; Accepted date: 28/11/2018; Published date: 05/12/2018

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Abstract

Present work was carried out at Motia Lake Bhopal, Madhya Pradesh, India on phytoplankton, zooplankton and icthyo fauna. During study period phytoplankton community was represented by four groups viz., Cyanophyceae, Bacillariophyceae, Chlorophyceae and Euglenophyceae. Among the four, Cyanophyceae was the most dominant group. The phytoplankton abundance was evident during monsoon season. The zooplanktons were represented by four groups viz., Rotifera, Cladocera, Copepoda and Ostracoda. Among these Rotifera exhibited numerical dominance. The ratio between Phytoplankton to Zooplankton was found to be 29.29: 1.00. The aquatic weeds found in the lake included species of Eichornia, Hydrilla, Marsilia, Meriophyllum, Chara, Ipomea, Najas and Vallisneria. The fish diversity in Motia Lake was represented by 20 genera belonging to the respective orders. They included major carps, exotic carps, murrels, cat fishes and other species.

Keywords

Phytoplankton, Zooplankton, Icthyo fauna, Motia lake

Introduction

In India water reservoirs have a rich and varied spectrum exceeding about 400 species. These wet lands are very important as they are good and useful sources to mankind in different ways. Some are used for irrigation, some for potable water supply, raw water supply, recreation and washing etc. With rapid urbanization, constant disturbance in demographic structure especially during second half of last century, all these water bodies have been subjected to various environmental problems. It results in the deterioration of water quality through (i) inflow sewage (ii) solid waste dumping (iii) other anthropogenic activities. These effected the fauna of water bodies and hence biodiversity of the lakes.

Seasonal rainfall and heavy discharge of water during the monsoon results in high flushing rate in most of the reservoirs which do not favour colonization by macrophytic communities. Inadequate availability of suitable substrate regards the growth of periphyton. Plankton by virtue of drifting habit and short turnover period, constitutes the major link in the trophic structure and events in the reservoir ecosystem. Fish production in reservoir is directly or indirectly dependent on the abundance of plankton. The physico-chemical properties of water determined the quality and quantity of plankton. The plankton community consists of organisms ranging from minute plants to small animals. Other two categories of life in an ecosystem are benthos and nekton. Benthos is the life at the bottom, like aquatic earthworms, insect larvae and certain fishes. Neton includes the larger swimming animals like fishes. Plankton is most essential for many fishes as food. The plankton is further divided into two main categories such as phytoplankton and zooplankton.

Phytoplankton includes algae, diatoms etc. They occupy the base of the food chain and produce the food material on which other organisms in the ecosystem sustain. The phytoplankton drifts about at the mercy of the wind and water movements. Algae consist of three major classes as chlorophyceae, cyanophyceae and bacillariophyceae. In natural water, algae are small and numerous, usually at a level of 102-106 cells/ml. Phytoplankton seems as a very good indicator of pollution of the fresh water. Blue-green algae form the main stay of phytoplankton community in the majority of the man-made reservoirs [1]. In late summer, the number of planktons declines as a thermocline develops and nutrients in surface are depleted by phytoplankton. This is called as summer minimum.

Zooplanktons are abundantly found in the shallow areas of a water body. The zooplankton unlike phytoplankton are particularly distributed horizontally and vertically in an ecosystem. The zooplankton forms an important group as it occupies an intermediate position in the food web. Many of them feeding on algae and bacteria and in turn being fed upon by fishes. They also indicate the trophic status of a water body. Their abundance increased in the eutrophic waters. They are also sensitive to pollution and many species are recognized as indicators of pollution. In fresh water reservoirs some of the organisms occasionally occur in appreciable numbers forming swarms. These swarms form bands or streaks or are arranged into thick and thin concentration and simulate the cloud effect and may give the water a stickingly different colour. The most commonly found zooplanktons are protozoans, crustaceans like cladocerans, copepods, ostracods and rotifers.

The ichthyofauna of a reservoir basically represents the fish faunal diversity. Indian reservoirs preserve a rich variety of fish species, on the basis of studies conducted so far, large reservoirs on an average harbour 60 species of fishes, of which 40 species contribute to the commercial fisheries. Indian major carps occupy a prominent place among the commercially important fishes. More recently, number of exotic species have contributed substantially to commercial fisheries. Being basically a carp country both the indigenous and exotic carps, catla, rohu, mrigal, silver carp, grass carp and common carp, account for a great bulk of the production.

Materials and Methods

The present study was conducted in a minor reservoir Motia Lake in the center of Capital City of Bhopal (2316’ N and 7736’ E; 550 meters above MSL) spreading over 7 hills. The water spread area is 10.89 hectares. The age of the reservoir is 90 years. The reservoir is located in Bhopal city with a wellbuilt tank bund. The reservoir water is used for many purposes including fishing activities. Bhopal city is called the City of Lakes. The two main lakes upper lake and lower lake, which provide livelihood and add to scenic beauty to the Bhopal city. Which is endowed with a number of eighteen water bodies developed over a period of 900 years. The present study was conducted in a minor reservoir Motia Lake in the center of capital city of Bhopal. The water spread area is 10.89 hectares. The age of the reservoir is 90 years. The reservoir is located in Bhopal city with a well-built tank bund. The reservoir water is used for many purposes including fishing The During this period study were conducted on biological organisms such as phytoplankton, zooplankton and ichthyofaunal diversity (Figure 1).

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Figure 1: Map Showing different Diversity..

Sampling procedure

The water samples were collected in five stations of the reservoir and one litre of water was collected in a wide mouth polythene bottle and tightly stoppered filled with surface water for biological analysis. Plankton net (mesh size 65 μm) was used to filter 50 litre of surface water to obtain 100 ml of the net plankton concentration. All the samples were packed in a cane basket, protected them from intense sunlight and contamination and were transported to the laboratory without any delay.

Biological analysis

Enumeration of Plankton: Sedgwick-Rafter cell of 1.0 ml capacity was used for counting microalgal forms, rotifers and micro crustaceans from net plankton samples. Depending on the population density the number of organisms in three SR cells was counted. Appropriate multiplication factor was used for the estimation of total number of organisms per litre.

Quantitative analysis: 50 litres water was collected and poured through plankton net and collected planktons are measured with measuring jar.

Since the water sources is not very big and do not found under the category of deep-water body, fishing is being conducted by traditional methods using the following craft and tackle.

The traditional catomarian which is improved with thermacole is used. 4 pieces of 36" × 18" × 6" size thermacole are united lengthwise to make one such box of a size of 72" × 18" × 12", wrapped in polythene cloth or a tarpolene or at time a thick gunny bag to make all the pieces as a single unit. This box will act as a float with holding the weight of person operating with a load of nets and fish. This is operated in water with the help of wooden oar.

Another method of going into water by the members is coracle. It is a wide basket of size made of a skeleton of M.S. iron spring/bar welded into required shape. The outer surface is covered with a tarpolene to enable floating water. Most of the fishing is being done by gill netting and, cast netting. All the nets consist of webbing, fastened to appropriate lines and rope only on Sundays and holidays. In the remaining months the fish were caught other than Sunday also.

After catching, the fishes were brought to the shores and segregated species-wise and sold out to customers or retailers or wholesalers or commission agents. The total catch of each species was weighed and calculated the total production of particular day. Then the whole month data was calculated species-wise. Finally, the catch of the month and then the year were calculated.

Results and Discussion

Plankton diversity: phytoplankton

The present observation on phytoplankton of the reservoir indicated that the communities of Cyanophyceae, Chlorophyceae, Bacillariophyceae and Euglenophyceae constitute the phytoplankton bulk in the present reservoir (Table 1; Plates 1-9).

Order Phytoplankton
Cyanophyceae
(9 Genra)
Anabena
Arthrospira
Lyngbya
Merismopodia
Microcystis
Merismopodia
Microcystic
Nostoc
Oscillatoria
Chlorophyceae
(12 Genra)
Spirogyra
Ulothrix
Volvax
Zygonema
Eudorina
Oedogonium
Closteridium
Scenodesmus
Cosmarium
Pediastrum
Microspora
Cladophora

Bacillariophyceae
(12 Genra)
Navicul
Bacillaria
Amphipleura
Fragillaria
Cymbella
Diatomella
Pinnularia
Synedra
Nitzschia
Gomphonema
Cyclostella
Diatoma
Euglenophyceae
(2 genra)
Euglena
Paranema

Table 1: The Phytoplankton of Motia Lake during 2011-2012 to 2012-2013.

Among phytoplankton community, the Cyanophyceae was found to be rich and dominated in the present reservoir. Cyanophyceae was found 69.67 in 2011-2012 and 50.27% in 2012-2013 in Motia Lake (Tables 2 and 3; Figure 2). Seven Cyanophyceae genera were found in the reservoir (Table 3). The common Cyanophyceae communities observed in the reservoir were Microcystic, Anabena, Phomidium, Oscillatoria, Merismopodia. Arthrospira and Nostoc.

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Figure 2: Seasonal fluctuations of phytoplankton in the Motia Lake.

During 2011 - 2012
S. No. Phytoplankton organisms/litre Pre-Monsoon Monsoon Post Monsoon Average
1. Cyanophyceae 60615 46315 32113 139043
2. Chlorophyceae 1630 1320 1090 4040
3. Bacillariophyceae 13920 7314 6920 28154
4. Euglenophyceae 3214 2712 1720 7636
  Total       178873
During 2012 - 2013
1. Cyanophyceae 64429 49810 36310 115870
2. Chlorophyceae 1875 1380 895 4150
3. Bacillariophyceae 13923 7912 6204 28039
4. Euglenophyceae 3254 2790 1680 7724
  Total       155783

Table 2: The seasonal fluctuations of Phytoplankton of Motia Lake during 2011-2012 and 2012-2013.

2011- 2012
S.No. Phytoplankton Total No. Percentage (%)
1. Cyanophyceae 35019 69.67
2. Chlorophyceae 4124 8.20
3. Bacillariophyceae 32012 6.36
4. Euglenophyceae 7918 15.75
  Total 50262  
1. Cyanophyceae 42713 50.27
2. Chlorophyceae 4125 4.83
3. Bacillariophyceae 3021 3.55
4. Euglenophyceae 7913 7.31
  Total 84963  
2011-2012 to 2012-2013
1. Cyanophyceae 77732 77.28
2. Chlorophyceae 8249 -2.27
3. Bacillariophyceae 66229 -17.29
4. Euglenophyceae 15832 -4.24
  Total 108.35  

Table 3: The Phytoplanktons and their percentages in Motia Lake during 2011-2012 and 2012-2013.

High quantum Cyanophyceae in pre-monsoon period in the reservoir of 139043 organisms/litre were observed during 2011-2012 and 115870 organisms/litre were observed during 2012-2013 (Figures 2 and 3). Maximum blue greens were found in February (60615 organisms/lit) during 2011-2012 and in March (62429 organisms/lit) during 2012-2013 (Table 2). The minimum value was found in January (32113 organisms/litre) during 2012-2013. The low phytoplankton values were found during post monsoon period in both the years of study.

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Figure 3: Fluctuations of Phytoplankton in the Motia Lake.

The second dominating phytoplanktons were the Bacillariophyceae, which contributes 13.17% and 12.21% to the total phytoplanktons community in the reservoir during study period. The pre-monsoon period was found to be favourable for the Bacillariophyceae plankton. 13920 organisms/l and 13923 organisms/litre were found in the reservoir during 2011-2012 and 2012-2013, respectively. The rich Bacillariophyceae planktonic blooms were observed in the reservoir during both the years. The planktonic bloom of Bacillariophyceae was observed to be decreased considerably with the onset of monsoon period, and further reduction in the blooming was also observed in post-monsoon season during the present study.

The Bacillariophyceae was found to be represented by twelve genera in Motia Lake. Among these genera the common plankton blooms recorded during the study period were Navicula, Bacillaria, Amphipleura, Fragillaria, Pinnularia, Diatomella, Synedra, Nitzchia, Cymbetta, Gamphonena Cyclostella and Diatoma (Table 1).

The maximum Bacillariophyceae plankton in the reservoir was found in February (13920 organisms/lit) during 2011-2012 and in March (13923 organism/lit) during 2012-13 high Chlorophyceae plankton was recorded in premonsoon period (1630 organisms/l and 1875 organisms/l) during 2011-2012 and 2012-2013, respectively. Low values were recorded (1090 and 895 organisms/lit) in post-monsoon period during study period (Table 4).

Order Zooplankton
Rotifera
(7 species)
Brachionus
Ceacane
Cephalodella
Filina
Epiphanus
Hexarthra
Keratella
Crustaceae   Cladocera
(11 species)
Alona
Cereodaphnia
Daphnia
Lactona
Leptodera
Leydiga
Macrothrix
Monia
Scapholebris
Sida
Sinocephalus
Copepoda
(5 species)
Canthocamptus
Cyclops
Diaptomus
Heliodiaptomus
Mesocyclops
Ostracoda (1 species) Cypris

Table 4: The Zooplankton of Motia Lake during 2011-2012 and 2012-2013.

The presence of abundant phytoplanktons during the study period was due to the presence of more nutrients in the reservoir. Extra-nutrients came from the domestic sewage of nearby areas which evolve towards mesotrophic nature from allgotrophic nature.

As usual temperature, nitrates, phosphate and angiosperm association were cited as important factors influencing the abundance and spatio-temporal distribution of diatoms. There was considerable evidence from Indian waters that diatoms were produce maximum during summer or winter or both as in the present reservoir [2,3].

It is clearly understood that the ecological parameters were potentially favorable for diatoms in the present reservoir, but they did not build up sizable population in the face of competition from blue-green algae. Similar observations were made by Devi [1], in Himayathsagar and Mir-alam. Vyas and Kumar [4] described phosphate and nitrate were more responsible for diatom abundance.

Low dominance of Euglenophyceae was recorded by Rao [1,2,5]. According to Cynthia high temperature, free CO2, low concentration of dissolved oxygen, large amounts of organic matter and iron were favourable for the growth of these flagellates. In Gandhisagar reservoir and Jari reservoir the dominance of chlorophyceae among phytoplankton was reported [6,7].

According to Unni et al. [8] ammonical nitrogen, phosphate and highly alkaline pH supports a very rich phytoplankton and zooplankton. (138 to 1725 ml and 9 to 320 nos-1) and almost 50% was dominated by Chlorphyceae in lake Powai [9].

The present study reveals that Englenophyceae domination was least among the phytoplankton population. Rao [2] in Mayira reservoir in Osmansagar and Himayathsagar reservoirs and Devi [1] in Ibrahimbagh and Shathamraj reservoirs reported the least domination of Chlorophyceae among the phytoplankton.

Oscillatoria was the most dominant form among all plankton in the present reservoir. It showed a continuous upward trend from December to September. The second most dominent phytoplankton of the reservoirs was Nitzschia of bacillariophyceae. It also showed an increasing trend during same period. High density of these phytoplankton was recorded at surface waters. Rao and Chowbey [6] recorded Nitzschia of bacillariophyceae as most dominant and Microcystis cyanophyceae as second dominant among plankton in Gandhisagar. Devi et al. [1,10,11] reported that Oscillatoria of Cyanophyceae in Ibrahimbagh and Nitzschia of Bacilloriophyceae in Shatamraj reservoirs were dominateds among the plankton.

Srivastava [12] reported that among plankton, Ceratium was the most dominating and the forms commonly seen were Peridium, Stanrastam, Synedra, Batryococus, Aphanocapsia, Pediastrum, Nitrocystos, Chrysamoebas along with some algal filaments. He has also reported the dominance of phytoplankton in summer in Rihand reservoir. Microcystis was dominant among the phytoplankton in Rihand reservoir. He has further reported that the plankton growth was moderate in Ramgarh reservoir as the water turbidity was high.

The present study revealed that the fluctuations of phytoplankton were similar to the fluctuation of physico-chemical parameters like temperature, pH, alkalinity, nitrates and phosphates. The seasonal fluctuation of the phytoplankton organisms with the fluctuation of physico-chemical condition of water had been reported by Rao et al. [1,6,10-11] (Figures 4-14).

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Figure 4: Showing Plate I structure.

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Figure 5: Showing Plate II structure.

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Figure 6: Showing Plate III structure.

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Figure 7: Showing Plate IV structure.

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Figure 8: Showing Plate V structure.

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Figure 9: Showing Plate VI structure.

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Figure 10: Showing Plate VII structure.

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Figure 11: Seasonal fluctuations of Zooplankton in the Motia Lake.

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Figure 12: Fluctuations of Zooplankton in Motia Lake.

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Figure 13: Showing Plate VIII structure.

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Figure 14: Showing Plate IX structure.

Plankton diversity: zooplankton

Zooplantons were represented by Rotifera, Cladocera, Copepoda and Ostracoda (Table 5, Figure 14). Among zooplankton, Rotifera was dominated followed by Copepoda, Cladocera and Ostracoda. Rotifera accounted for about 59.66% and 60.51% during 2011-2012 and 2012-2013 respectively (Figures 4 and 5). In Rotifera seven genera were found in the reservoir. Keratella, Brachionus, Hexarthra, Epiphanus, Filina, Ceprolodella and Ceacane were present during the two years. The maxima of Rotifera genera was observed in monsoon period (1993 organisms/lit and 2013 organisms/lit) during 2011-2012 and 2012-2013 respectively.

During 2011 - 2012
S. No. Species organisms/litre Pre-Monsoon Monsoon Post Monsoon Average
1. Rotifera 1398 1993 472 3063
2. Cladocera 129 156 251 536
3. Copepoda 549 832 350 1731
4. Ostracoda 142 169 73 384
  Total       6514
2012-2013
1. Rotifera 1430 2013 517 3960
2. Cladocera 139 169 235 543
3. Copepoda 567 890 362 1819
4. Ostracoda 172 201 78 451
  Total       6773

Table 5: The seasonal fluctuations of Zooplankton in Motia Lake during 2011-2012 to 2012-2013.

Copepoda was the second dominant group among the zooplankton in the reservoir. Five Copepoda genera were found in Motia Lake. The Copepodas accounted for about 27.17% and 29.08% during both the years (Figure 7). The Copepoda group was represented by Cyclops, Mesocyclops, Canthocamptus, Diaptomus, Heliodiaptomus. Maximum copepods were found during monsoon period (832 organisms/litre and 890 organisms/litre) during 2011-2012 and 2012-2013, respectively (Table 5; Figure 11).

Cladocera contributed 7.77% and 7.87% in total zooplankton in Motia Lake during the study period (Figures 4 and 5). Eleven genera were found Daphnia, Moina, Sinocephalus, Scapholebris, Leydiga, Cereodaphnia, Aloua, Sida, Loctona, Leptodera, Macrothrix (Table 4). The common genera observed were Daphnia, Cereodaphnia, Alova and Lactora. Maximum Cladocerans were found during post monsoon period (251 and 235 organisms/lit) during 2011-2012 and 2012-2013, respectively (Table 5). Highest number of Copepoda were observed in the Post Monsoon (350 organisms/lit) during 2011-2012 and 360 organisms/lit) in Post Monsoon during 2012-2013.

Among Crustacea, Ostracoda was the least group available in the present reservoir Ostracodes constitute only 5.38% and 2.52% among the total zooplanknic community during 2011-2012 and 2012-2013, respectively (Figures 4 and 5). Only Cypirus was found in the reservoir. Monsoon was observed as the peak period for this genus while lean period was the post-monsoon.

Rotifer formed an important component in the net plankton of the reservoirs. The shallow basin of these reservoirs with rich littoral macrophyte growth provided many ecological niches for these organisms. According to Pennak the extensive growth of Potatnogeton was said to inhibit the development of Rotifers.

Brachinoids formed the dominant group among Rotifers in the reservoir Filina Rotifers occurred as planktonic forms more or less throughout the period of investigation. These were known to be monofilter feeders, ex Filina. (Ruttener and Radwan stated that abiotic factors have a weak influence on the abundance and fertility of pelagic rotifers.

In the present work, the Rotifers occurred more during monsoon months in the reservoir. This indicated that the greater occurrence of loricate forms was related to the monsoon period with moderate temperature. The similar reports were given by Kumar et al. [13].

Cladocerons are widely distributed and have been considered as one of the most important components of the fish food, they may accumulate in the reservoirs in numbers large enough to create a problem for water work engineers, however, were considered beneficial for the removal of harmful bacteria from water [14]. Highest diversity as well as maximum number of new records of Cladoceran species observed in Santrogachi beel was presumably due to important bio-ecolgical relationship between macrophytes and zooplankton along with possible dispersal of zooplankton by avian agents.

In the alkaline pH found in the reservoir physico-chemical factors other than temperature did not apparently influence the periodicity and density of Cladocera. The similar observation was made by Rao [2] in Manjira reservoir Devi and Piska [1,10] in Ibrahimbagh and Shathamrai reservoirs.

It is generally recognized that Crustacean community structure depends upon the temperature and food conditions, predation by animals and competitive interaction among crustacean species. It has also been observed that decreasing importance of Copepods and increasing Cladocerans and Cyclopoid importance are associated with increasing productivity [14-20].

Free living Copepods are an essential link in the food chain occupying the intermediate trophic level between bacteria and algae on the hand and small and large plankton predators on the other. Though they are not as important as Cladocerans in the diet of fish, they are well known as important intermediate hosts for helminth parasites.

The seasonal fluctuations of zoopfankton did not always follow the fluctuations of physico-chemical parameters. The observed genera appeared only seasonally as festival vernal or hibernal and a few were of course perennial. Devi and Piska [1,10] reported that zooplankton was not always follows the fluctuations of physico-chemical parameters.

Devaraj et al. [14] reported that the plankton enrichment in Hemavathy reservoir depends on the nutrients brought in by the rain washings during monsoon from the catchment area. Total phytoplankton contributed to 48.85% as against 51.15% by zooplankton. Among the phytoplankton, Chlorophyceae dominated followed by Myxophyceae and Bacillariophyceae. Among the zooplankton, Cladocera dominated followed by Copepoda, Rotifera, Ostracoda. Devaraj et al. [14] reported that the abundance of plankton and bottom fauna on which aquatic population depends directly or indirectly is largely influenced by the interaction of a number of physico-chemical factors. They also pointed out that any single factor which is solely responsible for the influence of the abundance of plankton, but a combination of factors has certainly registered their influence.

Perumal and Santhanam [16] reported 37 species of zooplantons in Vedanthangal lake, Tamilnadu. Rotifers were dominated group in the lake. The order of abundance was Rotifera<Copepoda<Cladocera<Dinoflagellata<Oligohymenophora in the lake. Anjinappa and Kumar (2003) observed the Rotifera (48.46%), Cladocera (27.27%), Copepola (13.44%) and Ostracoda (10.83%) composition of zooplankton in Bonal reservoir, Karnataka. The domination of Rotifera species was clearly noticed.

Srinivas [17] reported that Hussainsagar lake has been subjected varying degrees of pollution and consequent eutrophication. The current patterns of plankton biodiversity in the lake revealed a marked decline in the species diversity and only pollution resistant species dominated replacing the freshwater indicating forms of earlier studies.

Zooplankton in general are very sensitive to changes in environment and constitute in aquatic food webs. Therefore, any adverse effect on zooplankton will reflect on productivity of system and most suitable indicator groups for assessment of any kind of aquatic pollution [18-30].

The observations made on the density of plankton in the reservoirs indicated that it can support Indian major carps and other fishes. Major carps showed preference for phytoplankton and zooplankton as major items of food. In addition, exotic common carp can also stock, as its natural food items are also available in sufficient quantities.

The quantity of plankton fluctuated between 0.5 to 0.75 ml/50 lit in the present reservoir during the study period. The ratio between phytoplankton and zooplankton was 8.58:1.0 (Tables 6 and 7). The domination of phytoplankton was clearly noticed.

2011- 2012
S.No. Zooplancton Total No. Percentage (%)
1. Rotifera 3778 59.66
2. Cladocera 492 7.77
3. Copepoda 1721 27.17
4. Ostracoda 341 5.38
  Total 6332  
2011-2012
1. Rotifera 3829 60.51
2. Cladocera 498 7.87
3. Copepoda 1840 29.08
4. Ostracoda 160 2.52
  Total 6327  
2011-12 and 2012-13
1. Rotifera 7607 60.09
2. Cladocera 990 7.82
3. Copepoda 3561 28.13
4. Ostracoda 501 3.95
  Total 12659  
Table 6: The Zooplankton and their percentages in Motia Lake during 2011-2012 and 2012-2013.

Order Group Fish
Cypriniformes Major carps (5) Labeo rohita (Rohu)
Catla catla (Catla)
Cirrhina mrigala (Mrigal)
Cyprinus carpio
(Common carp)
Ctenopharyngodon idella
(Grass crap)
Cypriniformes Minor carps (1) Labeo calbasu (Kalbasu)
Cypriniformes   Channiformes Carp min snows (3)   Murrels (2) Salmostoma bacaila
S. clupevides (Silver fish)
Amblyphamgodon (Mola)
Channa striatus
(Stripped murrel)
C. marulius (gaint murrel)
Siluriformes Cat fishes (4) Clarius batrachus (Maruf)
Heteropneustes fossilis (singhi)
M. Vittatus (Chinna Jella)
Rita rita (Rita)
Mastacembeliformes Snake fish (1) Mastacembelus armatus
  Ornamental fishes (2) Poecilia velifera (Black molly)
Gambusia affinis
(Mosquito fish)
Helostoma temmincki
(Kissing gourami)
Xiphophorusmaculates (Platies)

Table 7: Ichthyofunal diversity in Motia Lake.

Srivastava [19] reported that the ratio between zoo and phytoplankton was estimated to be 1:6.5 in Govindsagar reservoir. He found that the zooplankton was dominated only in September and October. Devi [1] reported the 1:2.08 and 1:2.39 ratio of zooplankton and phytoplankton in Ibrahimbagh and Shathamraj reservoirs, respectively.

Sakhare and Joshi [20] reported that phytoplankton of Yeldari reservoir constituted 84.03% of the total plankton, while zooplankton recorded only 15.97%, i.e., the ratio was 5.26:1 (p:z). Shrivastava [21] reported the dominance of zooplankton (79.9-87.8%) over phytoplankton (12.2-20.1%) in Ravishankar sagar, Chhattisgarh.

Aquatic weed in Motia Lake are like Eichhornia, Hydrilla, Marsilia, Meriophyllum, Chara, Ceratophyllum, Potamogeton, Najas, Typha and Vallisneria Nagar Nigam department is removing aquatic weeds regularly. This is mainly due to avoid the obstruction for boating operations in the reservoir. The weeds in the shallow areas of reservoir and were cleared during summer. The aquatic weeds were also eradicated by introducing grass carps. Aquatic macrophytes do not figure prominently in the community structure and trophic events of the reservoirs in India, barring some exceptional circumstances such as low water renewal, ageing of reservoir and pollution stress [22-45].

Ichthyofaunal diversity

Twenty genera of fishes were found in the reservoir (Table 7). Majority of genera belong to order cypriniformes. Five species of major carps (Cypriniformes), three species of carp minnows. (Cypriniformes), two species of murrels (Channiformes), four species of cat fishes (Siluriformis), two species of ornamental fishes and one species of Mastacembeliformes were found in Motia lake.

Based on their food and feeding habits, the fishes of Motia lake can be categorised into herbivores, carnivores, omnivores and planktonvores.

The abundance of ichthyofauna in the reservoir is depicted as shown in Table 8. The most abundant fishes were only the major carps like catla, rohu, mrigal, common carp and grass carp throughout the study period. Silver fish (bacaila), spotted and striated murrels, singhi were abundantly found during 2011-12, 2012-2013 and became less abundant or rare in remaining years. Silver fish is less abundantly found during 2011-2013 and became rare or absent in remaining years.

Fish Abundance
Labeo rohita (Rohu)
Catla catla (Catla)
Cirrhina mrigala (Mrigal)
Cyprinus carpio (Common carp)
Ctenopharyngodon idella (Grass crap)
+ + +
+ + +
+ + +
+ + +
+ + +
Labeo calbasu (Kalbasu) + +
Salmostoma bacaila
S. clupevides (Silver fish)
Amblyphamgodon (mola)
+ +
+
+ +
Channa striatus (Stripped murrel)
C. marulius (gaint murrel)
+ + +
+
Clarius batrachus (Marruf)
Heterupneustes fossilis (singhi)
M. vittatus (Chinna Jella)
Rita rita (Rita)
+ +
+ +
+
+
Mastacembelus armatus +
Poecilia velifera (Black molly)
Gambusia affinis (Mosquito fish)
+
+
+++ Most Abundance ++ Abundence + Less Abundence.  

Table 8: Ichthyofunal abundance in Motia Lake.

Devi [1] studied the ichthyofouna of Ibrahimbagh and Shathamarj reservoirs of Hyderabad and twenty-one genera of fishes were found in two reservoirs. Order Cypriniformes were dominated and followed by order Siluriformes, Channiformes and Percifomes.

Jain [23] reported 53 species of fish fauna and were grouped into seven categories in Rajasthan state. Sukumaran and Rahman [24] stated that majority of the reservoirs of Karnataka state has a large population of predatory fishes. 27 species of fishes belonging to six families have been encountered in Pong reservoir. Sakhare and Joshi [25] reported the ichthyofauna of Bori reservoir of Maharashtra. Total 20 species of fishes belonging to 14 genera falling under 4 orders (Cyprinoformes, Perciformes, Siluriformes and Osteoglossiformes). They also reported 34 species of fishes in reservoirs of Pharbhani district of Maharashtra. Suresh reported 54 fish species in Loktak lake, Manipur and 15 species are commercially important. Mahapatra [26] recorded abundance of cat fishes in Hirakud reservoir. About 43 species present, in which 18 of economically important.

Kumar [27] reported 51 ichthyofauna of 4 families in Govindsagar reservoir, Himachal Pradesh, out of which 12 fishes were commercially important. Sugunan [28] reported that on an average, large reservoirs (>5000/ha) in India harbor about 60 species of fishes. Jha reported that 49 ichthyofauna found Mahananda reservoir (280/ha).

Rao [29] reported that the Indian reservoirs harbour a rich variety of fish species. This is basically a consequence of the rich fauna diversity of the parent river system. Large reservoirs on an average will harbour about 60 fish species (range 40-90 species) with at least 40 fish species contribute to the commercial fishery. The fast growing gangetic carps (Indian major carps) occupy an important place both as natural and stocked species. Sultan and Chauhan reported 39 ichthyofouna in Pohnuj reservoir (U.P.) [46-55].

Srinivas [30] reported 32 species in Edulabad reservoir, Ranga Reddy District, out of which 13 species of Cypriniformes, 9 species of Siluriformes, 4 species each of Channiformes declined from 32 (2000-01) to 13 (2001-02) and further to 8 (2002-03) and only rohu, catla, grass carp and tilapia found most abundantly in the reservoir.

Krishna and Piska [31] reported 31 ichthyofauna in secret lake, Durgamcheru, Ranga Reddy District, belongs to Cypriniformes (14 species), Siluriformes (7 species), Channiformes (3 species), Perciformes (4 species) and a species each of Clupeiformes, Mastacembeliformes and Cyprinodontiformes and classified them into major carps (6), minor carps (3), cat fishes (7), murrels (3), trash fishes (6) and other fishes (6). They also reported that only 5 species most abundantly found during 2003 and 2004.

The major carps were most abundantly found in the reservoir due to the stocking of their seed every year. The most abundance of major carps in the reservoirs were also reported by many authors like Kumar et al. [1,23,27,31] opined that the stocking of their seed was main reason for their most abundance in the reservoir [56-90]. But Srinivas [30] reported that the decline of major carps, especially bottom dwelling carps like mrigal and common carp in a reservoir, Edualabad and stated that the decline was related to environmental pollution due to the entry of polluted river Musi water into the reservoir [91-139].

Rao [32] reported twenty-four species of fishes were found in the reservoir. Majority of genera belong to order cypriniformes. Five species of major carps (Cypriniformes), three species of carp minnows. (Cypriniformes), three species of murrels (Channiformes), six species of cat fishes (Siluriformes) and seven species of other fishes (Clupeiformes, Mastacembeliformes, Perciformes, Cyprinodontiformes) were identified in the reservoir [140-166].

References