INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 4, No 5, Copyright by the authors - Licensee IPA- Under Creative Commons license 3.

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1 INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 4, No 5, 2014 Copyright by the authors - Licensee IPA- Under Creative Commons license 3.0 Research article ISSN Growth status of Orange Chromide, Etroplus maculatus (Bloch) in Kayamkulam Lake, South Kerala (India) Department of Fisheries Resource Management, Kerala University of Fisheries and Ocean Studies (KUFOS), Panangad, P.O, Ernakulum, Kerala , India. sajanpolayil@gmail.com doi: /ijes ABSTRACT This study is an attempt to describe the growth status of Orange chromide, Etroplus maculatus in Kayamkulam Lake, Alappuzha (Kerala). The length-weight relationship was analysed using the formula W= a L b, which was further transformed into Log W = a+ b log L. The value of coefficient b (2.80) of the LWRs was in the expected range of cubes law, but the value is significantly different (p<0.05) from isometric value three and followed allometric growth pattern. Studies on relative condition factor (Kn) of E. maculatus revealed that the variations in Kn values can be related to spawning cycle as well as feeding intensity of fish. The study concluded that the lake condition is favourable for the growth of E. maculatus. Key words: Etroplus maculatus, length weight relationship, Kayamkulam Lake. 1. Introduction Growth fluctuation is more frequent in fishes of tropical and sub-tropical waters due to variations in seasons, multiple spawning and food composition (Lagler, 1956). The mathematical relationship between length and weight of fishes is a practical index suitable for understanding their survival, growth, maturity, reproduction and general well-being (Le Cren, 1951). In fishes, generally the growth pattern follows the cube law (Brody, 1945), such relationship will be valid when the fish grows isometrically. In such cases the exponential value must be exactly three. But in reality, the actual relationship between length and weight may depart from the ideal value due to environmental conditions or condition of fish (Le Cren, 1951). Etroplus maculatus (Boch) is one among the three Cichlid species native to Asia, the other being E. canarensis and E. suratensis (Manimegalai et al., 2010). Etroplus maculatus, orange chromide (Perciformes-Cichlidae) is an endemic species restricted in distribution to India and Sri Lanka (Ward and Wyman, 1977). Among the small sized fishes it has high economic importance and market value; locally it is sold from Rs / Kg. Some aspects of the orange chromide biology have been studied (Ward and Wyman, 1977; Kurup, 1982; Zoran and Ward, 1983; Samarakoon, 1983; Bindu and Padmakumar, 2012). However, no literature was available on the growth status of E. maculatus in Kayamkulam Lake. The objective of the present study is to describe the length-weight relationships (LWRs) and growth status of Etroplus maculatus from Kayamkulam Lake, Southern Kerala of India. Received on February 2014 Published on March

2 2. Materials and methods Fish specimens were collected from Kayamkualm Lake (9 12' 35" N latitude and 76 26' 09" E longitude), southern Kerala of India by using hook & line as well as cast net. Length of fishes were measured with mm scale and weighed with an electronic balance to the nearest 1mm and 0.1g respectively. The length-weight relationship was estimated by using the linear formula W= al b (Le Cren, 1951) as log W= log a + b log L; where W = weight of the fish, L = length of the fish and a= proportionality constant and b= exponent. For this, the observed length and weight of specimens were transformed into logarithmic values and regression analysis was carried out to calculate the a and b values. The 't' test was employed to confirm, whether the b value obtained in the linear regression was significantly different from the isometric value three. Condition factor (K) expressed as follows: K= W*100/ L 3. Where, W= observed body weight (g) and L= body length (cm). Relative condition factor (Kn) as per Le Cren (1951) is expressed as follows: Kn= W/^W. Where W = observed weight and ^W = calculated weight derived from length-weight relationship. Statistical analysis was done with SPSS package version Results and discussion Length weight relationship of 168 individuals of E. maculatus ranges, (cm) total length and (gm.) total weight were analysed. A scatter diagram of pooled samples of E. maculatus was obtained by plotting length against weight (Figs. 1). The length-weight data was pooled into a single equation which was calculated to be: Log W= log L (r =0.96). A positive correlation between length and weight was indicated by the higher correlation coefficient (r=0.96). Thus in the present study, total weight in relation to total length of E. maculatus follows allometric growth pattern. Figure 1: Logarithmic length-weight relationships of Etroplus maculatus from Kayamkulam Lake, Kerala Most of the common fishes of tropical and temperate regions are their b values ranging from 2.0 to 4.0 (Le Cren, 1951). But the length-weight relationship does not always obey the cube s law in different fishes (Hile, 1936; Sekharan, 1968). In this study, the b value estimated from length-weight relationship of E. maculatus was (CI of 95 % of 2.69 and < 95 % of 2.91), which was of expected range of b value (Le Cren, 1951), but statistically b value was significantly different from the ideal value three (df=168; t=-3.469, p=0.0007), it indicated that the E. maculatus follows allometric growth pattern. Mercy et al. (2008) has 627

3 found the pooled b value to be 3.12 (df = 8) in E. maculates from Rivers of Kerala. The lower and upper 95% confidence limits of b of pooled sample do not include the isometric value 3.0, i.e. specimens shape must increase in some other dimensions, whether breadth or thickness, in greater proportion than they increase in length (Fulton, 1904). According to Wootton (1992), b < 3 indicates that the fish gets relatively thinner as they grow larger while b > 3, it is plumper as it grows larger. Similarly, b value less than three has been reported in Tor tor (Malhotra, 1982), Labeo dero (Malhotra and Chauhan, 1984), Labeo dyocheilus (Malhotra, 1985), Cyprinus carpio communis & Ctenopharyngodon idella (Dhanze and Dhanze, 1997) and Rasbora daniconius (Sunil, 2000). The logarithmic equations obtained in different length group were as follows: Table 1: Logarithmic equations of different length group Length N a b sb r t % CL of b S G NS IG NS IG S AG N= number of sample, a= intercept, b=regression coefficient, sb= std. error of b, r= correlation coefficient, t= t-value, S= significance, CL= Confidence level, IG= Isometric growth, AG= Allometric growth. Figure 2: Logarithmic LWRs of Etroplus maculatus (Smaller group) Figure 3: Logarithmic LWRs of Etroplus maculatus (Larger group) 628

4 In this study, there was a variation in the exponent (b) value between two length groups, i.e., b value (2.89) for cm length group (t =-1.351, df = 77, p =0.1806) and b value (3.02) for cm length group (t =-0.122, df = 91, p =0.2256). However, these b values were not significantly different from the isometric value of three (p<0.05). Among these two groups, the larger fish group ( cm) had the highest regression coefficient (3.02), which shows that their weight increases at a comparatively higher rate than the smaller fish. These changes in 'b' value within length group may be due to the influence of numerous factors viz., growth difference, seasonal fluctuations, change in physiological condition during spawning periods, gonad development, sex, physicochemical conditions of the environment and nutrition conditions of the environment (Sinha, 1973; Prasad and Ali, 2007). Le Cren (1951) states that the LWRs in fishes is probably related to the seasonal variations, as fishes do not retain the same shape or body contour throughout the year. So there should be slight change in slope values in different seasonal studies. Total weight of fish may also be altered by the weight of the stomach content depending on the food ingested just before weighing (Muth and Smith, 1974). A scatter diagram of logarithmic length-weight relation of two length groups of E. maculatus were plotted in Figures 2 and 3. Figure 4: Lengthwise variation in condition factor (K) of Etroplus maculatus. Figure 5: Lengthwise variation in relative condition factor (Kn) of Etroplus maculatus. Condition factor (K) can be used as an index to assess the status of the aquatic ecosystem in which fish live (Anene 2005). The mean values of condition factor (K) and relative condition factor (Kn) worked out for different size groups of E. maculatus were plotted in Fig. 4 & Fig. 5 respectively. Relative condition factor (Kn) value of 0.89 was worked out in cm length group, followed by a decreasing trend towards cm size group (0.66). Thereafter, Kn value increased up to 0.81 in cm length group. Fluctuations in the condition of different length group may be in relation to their reproductive cycle, feeding rhythms or physico-chemical factors of environment, age, physiological state of fish or some other unknown factors as suggested by many workers, Le Cren (1951); Gairola et al. (1990) and 629

5 Kumar and Kurup, (2010). The results of the present investigation on length-weight relationships and condition factor of Etroplus maculatus indicates that the Kayamkulam lake habitat is conducible for the optimum growth of the fish. The present study provides baseline information on the growth status of E. maculatus that will be useful for researchers in future study. Acknowledgements Author express his sincere thanks to Dr. T.V. Anna Mercy, Kerala University of Fisheries and Ocean Science (KUFOS), Panangad, Ernakulum for providing facilities to carry out this study. This study would not have been possible without the support and active involvement of S. Shibu, R. Ratheesh, S. Balasubahmaniyan, S. Shajan and P. Sarath (Fisheries Exploration and Conservation Forum). 4. References 1. Anene A. (2005), Condition factors of four cichlid species of a man-made lake in Imo state, Southeast, Nigeria. Turkish Journal of Fisheries and Aquatic Science, 5, pp Bindu L. and Padmakumar KG. (2012), Breeding behaviour and embryonic development in the Orange chromide, Etroplus maculatus (Cichlidae, Bloch 1795), Journal of Marine Biological Association of India, 54(1), pp Dhanze R. and Dhanze JR. (1997), Biology of scale carp and grass carp 1. Lengthweight Relationship and Growth Performance under the Agro Climatic Zone of Himachal Pradesh, Indian Journal of Fisheries, 44, pp Gairola DO., Singh V., Malhothra SK., Nanda S and Ghildiyal RP. (1990), Ponderal Index and Length-weight Relationship of Barilius bendelisis (Ham.). Indian Journal of Fisheries, 37, pp Hile R. (1936), Age and growth of the cisco, Lencichthys artidi (Le Sueur) in the lakes of north-eastern highlands, Wisconsin. Bulletin of the United States Bureau of Fisheries, 48, pp Le Cren ED. (1951), The length-weight relationship and seasonal cycle in gonad weight and condition in the perch (Perca fluviatilis). Journal of Animal Ecology, 20, pp Kumar TGM and Kurup BM. (2010), Length-weight Relationship and Relative Condition Factor of Puntius carnaticus (Jerdon, 1849). Fishery Technology, 47(1), pp Malhotra SK. (1982), Bionomics of Hillstream Cyprinids III. Food, Parasites and Length-Weight Relationship of Garwhal mahaseer, Tor tor (Ham.). Proceedings of the Indian Academic Science, 91, pp

6 9. Malhotra SK. and Chauhan RS. (1984), Bionomics of Hill Stream Cyprinids IV. Length-Weight Relationship of Labeo dero (Ham.) from India. Proceedings of the Indian Academic Science, 93, pp Malhotra, S. K. (1985), Bionomics of the Hill stream Cyprinids 1. Food Parasites and Length-weight Relationship of Labeo dyochilus. Proceedings of the Indian Academic Science, 94, pp Manimegalai MS., Karthikeyeni S., Vasanth S., Arul Ganesh T., Siva vijayakumar and Subramanian P. (2010), Morphometric analysis-tool to identify the different variants in a fish Species Etroplus maculatus. International Journal of Environmental Science 1(4), pp: Mercy TVA, Eapen J. and Rajesh KB. (2008), Length-weight relationship of sixteen species of indigenous ornamental fishes of the Western Ghats of India. Indian Journal of Fisheries, 55(4), Muth K. and Smith LL. (1978). The Burbut fishery in Lake of the Woods. Technical Bulletin, 296, p Pauly D. (1993), Editorial fish byte, Naga, 16, p Prasad G. and Ali PHA. (2007), Length-Weight relationship of a cyprinid fish Puntius filamentosus from Chalakkudy River, Kerala. Zoos Print Journal, 22(3), pp Samarakoon JI. (1983). Breeding patterns of the indigenous cichlids Etroplus suratensis and Etroplus maculatus in an estuary in Sri Lanka. Mahasagar, 16(3), pp Samat AMN., Shukor AG., Mazlan A., Arshad and Fatimah MY. (2008), Lengthweight Relationship and Condition Factor of Pterygoplichthys pardalis (Pisces: Loricariidae) in Malaysia Peninsula. Research Journal of Fisheries and Hydrobiology, 3(2), pp Sekharan KV. (1998), On the catfish resources of the coasts of Andhra Pradesh, Orissa and West Bengal. In: Proceedings of the symposium on living resources of the seas around India. Cochin. pp Sinha AL. (1973), Length-weight relationship of a freshwater catfish, Clarias batrachus (Linn.) Indian Journal of Zoology, 14(2), pp Sunil MS. (2000), Length-weight Relationship in Rasbora danioconius (Ham.) from Achenkoli River, Pathanamthitta. Kerala, India. Indian Journal of Fisheries, 47, pp Ward JA. and Wyman RL. (1977), Ethology and ecology of cichlid fishes of the genus Etroplus in Sri Lanka: Preliminary findings. Environmental Biology of Fishes, 2(2), pp

7 22. Wootton JT. (1992), Indirect effect, prey susceptibility, and habitat selection: impacts of birds on limpets and algae. Ecology, 73(3), pp Zar JH. (1984), Biostatistical Analysis (Second Edition). New Jersey: Prentice-Hall. 24. Zoran MJ. and Ward JA. (1983), Parental egg care behaviour and fanning activity for the orange chromide, Etroplus maculatus. In: D. I. G. Noakes, D. G. Lindquist, G. S. Helfman and J. A. Ward (Eds.), Predators and Prey in Fishes, Dr. W. Junk, The Hague, Netherlands. pp