impact of water quality factors ON GROWTH and survival of fishes Cultured at s.k. Fish Farm, Mangalanayakipuram, Thiruvarur District, Tamil Nadu Dr. A. Amsath P.G. and Research Department of Zoology, Khadir Mohideen College, Adirampattinam-614 701. aamsath@gmail.com

INTRODUCTION Aquaculture major carps Freshwater fish culture Good Water quality Management strategies

OBJECTIVE The present study was designed to investigate the impact of water quality factors on growth and survival of fishes Cultured at S.K. Fish Farm, Mangalanayakipuram, Thiruvarur District.

MATERIALS AND METHODS Description of the study area The present investigation was carried out in a polyculture pond at s. k. Fish Farm, which is situated in Mangalanayakipuram , Thiruvarur District. The area of the s. k. Fish Farm is 2 hectares consists of 2 ponds. The extensive culture pond 1 was selected for the present study. The water spread area of each pond is about 0.95 hectare (Fig. 1).

Photograph showing Study Area Agniar Estuary, Rajamadam

Experimental Fish The fish fingerlings (5 cm in length) were selected as seed for the culture. The seeds were obtained from M/s Meenatchi Fish Hatchery Farm, Kottur, Mannargudi Taluka, Tiruvarur District. They were transported in oxygenated polythene bags. The total seeds introduced were 3000 (Cala: 1000; Roghu: 750; Mrigal: 650, Common carp: 600). The observations were started from the stocking date 06.08.2007 to harvest day 30.06.2008 for a period of 330 days.

Mystus gulio

Labeo rohita

Cirrhinus mrigala

Cyprinus carpio

Analysis of Water Quality Parameters For the present investigations, the water quality parameters like temperature, pH, Turbidity, Dissolved oxygen, CO2, Salinity, Total hardness, Calcium, Magnesium, Phosphate, Ammonia, Nitrite were analysed by the method of Strickland and Parson (1968). These parameters affect the growth and survival of fishes. Therefore, these parameters were observed for the period of 330 days.

Assessment of Growth and survival Feeding programmed was started from the first day. The fishes were fed with fish feed which is composed of rice bran, groundnut oil cake and soya bean meal (2:2:1 ratio respectively). First month of the culture period feeding frequency was 2 times/day morning 6 am and evening 6 pm. Second month the same was three times as 6 am, 2 pm and 8 pm. From 60th day to till harvest 4 times feeding followed as 6 am, 12 noon, 6 pm and 10.30 pm.

2.4 Assessment of Growth and survival To assess the growth, the fishes were collected from the pond using the check-tray to measure the body length by scale and the weight by digital pan balance. The fishes sampling also made using cast net every 10 days till harvest. 5 to 6 cast net samples were castled by net and each cast covered the spreading the area of 10 square meters. From 5 to 6 nets the average numbers of fishes/net were calculated. From this total number of fishes in the pond was calculated. During sampling number of fishes per kilogram was counted and the growth variations (length and weight gain) from the previous sampling was recoded. Survival of the fishes assessed based on the fingerlings allowed and number of fish catches every month.

3. RESULTS The present study has been carried out in a polyculture fish pond at K. Fish Farm, Mangalanayakipuram for the period of 330 days from the introduction of fingerlings, Catla catla, the rohu Labeo rohito, the mrigal, Cirrhinus cirrhosus and the common carp, Cyprinus carpio. (06.08.2007) to the harvest day (30.06.2008). In the present study, all the physico-chemical parameters like water temperature, turbidity, pH, dissolved oxygen, carbon dioxide, salinity, total hardness, calcium, magnesium, phosphate, ammonia and nitrite average values were either increased or decreased gradually from the month of August 2007 to June 2008 in the fish polyculture pond.

Table 1: The data on water quality parameters of polyculture fish pond at K. Fish Farm, Mangalanayakipuram. Month of culture Tempera-ture (C) Turbitity (cm) pH Oxygen (ml/1) Carbon-dioxide (ppm) Salinity ( ppt) Total Hardness (mg/L) Calcium Magne-sium Phosphate Ammonia (mg/l) Nitrate (g/l) 1 (Aug 2007) 29.5± 0.5 32.5± 1.6 7.8± 0.3 6.3 ± 0.5 27.4 ± 1.4 0.4 ± .02 100.5 ± 4.4 28.3 ± 3.2 7.2 7.7 0.3 9.0 ± 0.2 2 (Sep 2007) 29.1± 30.5± ± 0.3 7.3 27.0 ± 0.02 112.7 ± 2.4 24.7 ± 1.5 ± 1.2 7.4 8.7 3 (Oct 2007) 28.5 ± 0.6 29.4 7.6 8.5 29.5 ± 2.5 114.5 22.8 15.5 ± 3.4 8.3 ± 0.4 4 (Nov 2007) 27.7 26.0 10.3 31.2 ± 0.7 0.2 ± 0.03 118.2 ± 3.5 23.4 ± 4.2 13.7 ± 3.6 0.6 8.4 5 (Dec 2007) 27.2 ± 0.8 25.8 ± 4.5 10.6 28.0 ± 1.3 0.1 113.0 ± 2.6 26.2 ± 2.3 16.2 ± 2.7 9.7 6 (Jan 2008) 28.3± 23.5± 7.1 9.6 17.3 0.9 7 (Feb 2008) 28.8 22.4 7.2± 0.2 9.5 1.2 22.3 1.1 7.5 8(Mar 2008) 19.0 ± 0.07 119.2 0.7 9 (Apr 2008) 30.5 18.8 5.6 ± 0.04 6.2 10 (May 2008) 30.9± 17.5± 17.8 1.4 6.7 11 (Jun 2008) 30.7± 102.7 25.7 18.3 1.5

The data indicates that the physico-chemical status of pond water of S The data indicates that the physico-chemical status of pond water of S. K. Fish Farm, Mangalanayakipuram did not vary significantly. The levels were well within the optimum levels.

Growth of fish In the present study the growth of fish was gradually increased in polyculture pond. The weight of the animal gradually increased after 30 days with increased length of animal. There was a direct relationship between weight and length of the animal.

Survival of fishes The total seeds introduced in the ponds were 3000 (Cala: 1000; Roghu: 750; Mrigal: 650, Common carp: 600) in the first day of culture. But at the end culture day, the harvested fishes were only 2500. The present study indicates that the mortality of the fishes were more in their early stages comparing with later stages.

Table 2: The data on feed, length, weight and survival of fish at S. K Table 2: The data on feed, length, weight and survival of fish at S.K. Fish Farm. Month of culture Weight of feed (Kg) Weight (gm) Fish length (cm) Survival (%) 1 (Aug 2007) 10 20 -50 5-10 3000 2 (Sep 2007) 20 50-150 10-12 2700 3 (Oct 2007) 30 150-250 12-18 2650 4 (Nov 2007) 40 250-350 18-22 2625 5 (Dec 2007) 50 350-550 22-25 2600 6 (Jan 2008) 60 550-600 25-27 2580 7 (Feb 2008) 65 650-700 27-30 2550 8 (Mar 2008) 70 700-750 30-33 2530 9 (Apr 2008) 75 750-800 33-36 2520 10 (May 2008) 80 800-900 36- 38 2510 11 (Jun 2008) 85 900-1500 38-42 2500

CONCLUSION The result indicates that water quality parameters are not widely fluctuated and they are in normal level. The present investigation also reveals the better growth of fishes in polyculture pond at S. K. Fish Farm, Mangalanayakipuram. The normal growth of fishes in the culture pond was due to good maintenance of water quality parameters.Therefore, normal growth of fishes was observed in the polyculture pond