Universities Research Journal 2011, Vol. 4, No. 2

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1 Universities Research Journal 2011, Vol. 4, No. 2 Fecundity (F), Gonadosomatic Index (GSI), Hepatosomatic Index (HSI), Condition Factor (K) and Length-weight Relationship (LWR) in Channa orientalis Bloch & Schneider, 1801 Thant Zin 1, Aye Aye Than 2 and Thi Thi Naing 3 Abstract A total of 302 Channa orientalis Bloch & Schneider, 1801 was sampled from Thamandaw Village, Pathein Gyi Township, Mandalay Region to inspect the reproductive condition during June 2007 to May Fecundity (F), gonadosomatic index (GSI), hepatosomatic index (HSI), condition factor (K) and length-weight relationship (LWR) were evaluated. The lowest fecundity was observed as ± in standard length class range of cm whereas the highest fecundity of ± in standard length class range of cm. Regarding to body weight, the lowest fecundity was found to be ± in body weight class range of g while the highest fecundity to be ± in weight class range of g. Monthly variations of GSI in both sexes showed the higher values during the period from March to October when HSI values were lower. Based on the values of GSI and HSI, the reproductive cycle of C. orientalis is designated into prespawning period (January - February), spawning period (Mach - October), and postspawning period (November - December). The correlation coefficient for length-weight relationship was found to be 0.93 for male and 0.91 for female. The value of regression coefficient for both sexes (b) was observed to be greater than 3 indicating the positive allometric growth pattern. The sex ratio for male to female was 1: 0.88 and the difference was not significant (p > 0.05). The data revealed that C. orientalis is a seasonal breeder and reproduction took a longer duration of time. Key words: Channa orientalis, fecundity (F), gonadosomatic index (GSI), hepatosomatic index (HSI), condition factor (K), length-weight relationship (LWR), sex ratio 1. Associate Professor, Department of Zoology, University of Mandalay 2. Assistant Lecturer, Department of Zoology, Yadanapon University 3. Assistant Lecturer, Department of Zoology, Mandalay University of Distance Education

2 48 Universities Research Journal 2011, Vol. 4, No. 2 Introduction The knowledge of reproductive biology of fish is a prerequisite of fish production. Some of the parameters of fish biology include fecundity (F), gonadosomatic index (GSI), hepatosomatic index (HSI), condition factor (K), and length-weight relationship (LWR). These parameters are used to assess the reproductive condition of fish. A thorough knowledge of the fecundity of fish is essential for evaluating the commercial potentialities, stock study, life history study, particular culture and actual management of the fishery (Lager et al., 1956; cited by Rheman et al., 2002). Fecundity is an important parameter in fishes for determining the reproductive potential of species. Monthly variations of GSI provide the reasonable indicator of reproductive seasonality for fish. The seasonal timing of reproduction, spawning time is often identified from changes in the gonadosomatic index which determines reproductive season (Arruda et al., 1993). The hepatosomatic index is the ratio of liver weight to body weight. The liver is a key organ in fish production of vitellogenin, the yolkprecursor (Koob and Callard, 1999; cited by Lucifora et al., 2002). Hepatosomatic index is important because it describes the fish's stored energy and is a good indicator of recent feeding activity (Tyler and Dunns, 1976). Indexes of condition which can be determined easily and quickly are needed in routine fisheries surveys and are good predictors of the body composition and growth rate of fish (Cui and Wootton, 1988). Condition factor (K) is quantitative parameters of the well-being state of the fish and reflects feeding condition. This factor varies according to influences of physiologic factors, fluctuating according to different stages of the development. Differences in the condition factor have been interpreted as a measure of histological events such a fat reservation, adaptation to the environment and gonadal development (LeCren, 1951). Length-weight relationship is considered to be one of the important biological information in order to describe mathematical relationship between variances, length and weight. Because information about length and weight attributes of growth are essential in understanding this relation and length-weight relationship has been used in fish biology (Costa and Araùjo, 2003).

3 Universities Research Journal 2011, Vol. 4, No Relationship between length-weight for fish in a given population can be analysed by measuring weight and length of the same fish throughout their life or of a sample of fish taken out at a particular time (Wootton, 1998; cited by Zafar et al., 2003). In light of above, the paper describes the reproductive biology of Channa orientalis Bloch & Schneider, Materials and Methods Study area Channa orientalis specimens used in this study were taken from Thanmadaw Village, Patheingyi Township, Mandalay Region. The area is situated at intersection of North latitude 21 56' and East longitude of 96 09'. Study period The duration of the study period was from June 2007 to May Collection of specimens A total of 302 (164 males and 138 females) C. orientalis was collected and used in this study. Identification of species Species identification was followed after Talwar and Jhingram (1991). Measurements and dissection The standard length was measured to the nearest centimeter and weight to the nearest gram. Then ventro-lateral dissection was made and the sex noted. The gonads and liver were removed and weighed by digital balance. The ovaries were preserved in 10% formalin for fecundity. Parameters employed The monthly changes in the gonadosomatic index (GSI) and hepatosomatic index (HSI) were calculated using the formulae given by Wingfield and Grimm (1977). Gonad weight GSI = 100 Body weight

4 50 Universities Research Journal 2011, Vol. 4, No. 2 Liver weight HSI = 100 Body weight The condition factor (K) was calculated according to formula stated by Salam and Davies (1994). Body weight K = Length To calculate the fecundity, subsamples were taken from the ovaries and weighed. The numbers of eggs in these subsamples were used to calculate the total number of eggs in each ovary. ovary weight egg number in the subsample Absolute fecundity = subsample weight (Yeldan and Avsar, 2000) The sex ratio was calculated on monthly basis. Statistical analysis The relationship between each paired parameters was calculated using regression equation given by Bailey (1968). Sex ratio was analysed using Chi-square (χ 2 ) test (Bailey, 1968). Results Fecundity (F) The eggs from 58 mature females were analyzed for fecundity. Relation of fecundity with standard length and body weight are shown in Table 1 and 2 respectively. Absolute fecundity ranged from ± ± in mean length classes of ± ± 0.35 cm (Table 1) and from ± ± in mean weight groups of ± ± 9.15g (Table 2). a.fecundity and standard length Fecundity (F) and standard length (L) in Channa orientalis showed a linear poor relation with correlation coefficient r = (Fig. 1). F = L

5 Universities Research Journal 2011, Vol. 4, No b. Fecundity and body weight A linear poor relation was observed between fecundity and body weight with coefficient of correlation r = (Fig. 2). F = W c. Fecundity and ovary weight A high correlation was found between fecundity and ovary weight r = 0.88 (Fig. 3). F = O Gonadosomatic index (GSI) Changes in monthly GSI values of both sexes are given in Table 3 and 4. It is observed that the lowest mean GSI values were obtained in November 0.15 ± 0.04 for males and in December 0.58 ± 0.15 for females. The highest mean values occurred in August 0.45 ± 0.09 for males and in May 2.96 ± 1.73 for females. Hepatosomatic index (HSI) Monthly changes of HSI values for both sexes are shown in Table 3 and 4. The minimum mean values of HSI were found in March for males 0.84 ± 0.30 and in July for females 1.08 ± The maximum mean values of HSI were found in December 1.46 ± 0.15 for males and in January 1.60 ± 0.24 for females. Condition factor (K) Monthly variations of the condition factor in both male and female are shown in Table 3 and 4. The lowest mean K values were observed in March 1.50 ± 0.24 for males and in May 1.51 ± 0.17 for females. The highest mean values of K for both sexes were obtained, 1.94 ± 0.39 for males and 1.98 ± 0.19 for females in February. Length-weight relationship (LWR) Monthly means of the standard length and body weight for the males and females are given in Table 5 and 6 respectively. A highly correlation was observed between standard length and body weight for both sexes (Fig. 4 and 5) with correlation coefficient r = 0.93 in male and r = 0.91 in female.

6 52 Universities Research Journal 2011, Vol. 4, No. 2 A positive allometric growth was found in both males and female (b > 3). Sex ratio Monthly changes in the percentage ratio of males to females are presented in Table 7. The overall sex ratio of male to female was 1: 0.88 and the percentage occurrence of males % was relatively higher than female 45.69%. Table 1. Relation between standard length and fecundity in Channa orientalis during June 2007 to May 2008 No. of fish examined Standard length (cm) Absolute fecundity Range Mean ± SD Total Range Mean ± SD ± ± ± ± ± ± ± ± Table 2. No. of fish examined Relation between body weight and fecundity in Channa orientalis during June 2007 to May 2008 Body weight (g) Absolute fecundity Range Mean ± SD Total Range Mean ± SD ± ± ± ± ± ± ± ±

7 Universities Research Journal 2011, Vol. 4, No Absolute fecundity y = x r = n = Standard length (cm) Fig. 1 Relation between standard length and absolute fecundity in Channa orientalis during June 2007 to May y = 25.35x r = n = 58 Absolute fecundity Body weight (g) Fig. 2 Relation between body weight and absolute fecundity in Channa orientalis during June 2007 to May 2008

8 54 Universities Research Journal 2011, Vol. 4, No y = x r = 0.88 n = 58 Absolute fecundity Ovary w eight (g) Fig. 3 Relation between ovary weight and absolute fecundity in Channa orientalis during June 2007 to May 2008 Table 3 Monthly means of the GSI, HSI and K in male Channa orientalis from June 2007 to May 2008 Months No. of fish examined Range GSI HSI K Mean ± SD Range Mean ± SD Range Mean ± SD June, ± ± ±0.37 July, ± ± ±0.25 Aug, ± ± ±0.19 Sep, ± ± ±0.17 Oct, ± ± ±0.31 Nov, ± ± ±0.12 Dec, ± ± ±0.12 Jan, ± ± ±0.13 Feb, ± ± ±0.39 Mar, ± ± ±0.24 Apr, ± ± ±0.15 May, ± ± ±0.19

9 Universities Research Journal 2011, Vol. 4, No Table 4 Monthly means of the GSI, HSI, and K in female Channa orientalis from May 2007 to April 2008 Months No. of fish examined Range GSI HSI K Mean Mean Range Range ± SD ± SD Mean ± SD June, ± ± ±0.21 July, ± ± ±0.15 Aug, ± ± ±0.08 Sep, ± ± ±0.12 Oct, ± ± ±0.29 Nov, ± ± ±0.15 Dec, ± ± ±0.17 Jan, ± ± ±0.13 Feb, ± ± ±0.19 Mar, ± ± ±0.14 Apr, ± ± ±0.13 May, ± ± ±0.17 Table 5 Monthly means of the standard length and body weight in male Channa orientalis from June 2007 to May 2008 Months No. of fish examined Standard length (cm) Body weight (g) Range Mean ± SD Range Mean ± SD June, ± ±9.33 July, ± ±11.20 Aug, ± ±14.08 Sep, ± ±14.09 Oct, ± ±14.68 Nov, ± ±10.58 Dec, ± ±3.37 Jan, ± ±12.34 Feb, ± ±11.29

10 56 Universities Research Journal 2011, Vol. 4, No. 2 Months No. of fish examined Standard length (cm) Body weight (g) Range Mean ± SD Range Mean ± SD March, ± ±15.96 April, ± ±16.93 May, ± ±8.13 Table 6 Monthly means of the standard length and body weight in female Channa orientalis from June 2007 to May 2008 Months No. of fish examined Standard length (cm) Body weight (g) Range Mean ± SD Range Mean ± SD June, ± ±5.73 July, ± ±3.55 Aug, ± ±9.12 Sep, ± ±11.85 Oct, ± ±14.38 Nov, ± ±7.95 Dec, ± ±5.78 Jan, ± ±14.61 Feb, ± ±13.02 March, ± ±9.10 April, ± ±13.89 May, ± ±21.19

11 Universities Research Journal 2011, Vol. 4, No y = x r = 0.93 n = Body weight (g) Standard length (cm) Fig. 4 Relationship between the standard length and body weight of male Channa orientalis from June 2007 to May y = x r = 0.91 n = Body weight (g) Standard length (cm) Fig. 5 Relationship between the standard length and body weight of female Channa orientalis from June 2007 to May 2008

12 58 Universities Research Journal 2011, Vol. 4, No. 2 Table 7 Monthly changes in the percentage sex ratio (M/F) during June 2007 to May 2008 Months No. of fish observed Male Female χ 2 Sex-ratio No. % No. % M/F June, :1 July, :0.93 Aug, :0.77 Sep, :0.68 Oct, :0.81 Nov, :0.77 Dec, :1 Jan, :0.85 Feb, :1 March, :0.52 April, :1 May, :1.27 Total :0.84 Discussion One hundred and sixty four males and 138 females Channa orientalis were collected during June 2007 to May 2008 for the evaluation of fecundity (F), gonadosomatic index (GSI), hepatosomatic index (HSI), condition factor (K), length-weight relationship (LWR), and sex ratio. Bagenal (1967) reported that length and weight are reliable indicators of the capacity of egg production once the fecundity increased with the increase of the fish in size and weight (cited by Lampert et al., 2004). This condition is also found in the present work, in which the number of eggs increases with an increase of length and weight of fish. Gonadosomatic index (GSI) indicates the gonadal development and maturity of fish. It increased with the maturation of fish and declined thereafter (Parameswarn et al., 1974; cited by Rheman et al., 2002). Yeldan and Avsar (2000) also reported that gonadosomatic index (GSI) is widely

13 Universities Research Journal 2011, Vol. 4, No used especially for the bony fishes in order to examine the spawning period because its value is directly related to the development of the gonads. In the present study, monthly variation in GSI revealed that both sexes followed nearly the same pattern. GSI showed higher values during the period from March October, while the lower ones occurred during the period from November to February. Therefore, the period from March to October may be regarded as the spawning season. Due to the fact that the spawning time took for a long time, mature gonads were observed almost all of the study period. Based on the GSI values, the reproductive cycle of C. orientalis can be divided into prespawning period (January to February), spawning period (March to October) and postspawning period (November to December). Because of longer duration of reproductive period, the resting phase does not occur in this species. Normally, variations of hepatosomatic index (HSI) imply energy storage for reproduction (Hoars et al., 1983, N'Da and Daniel, 1993; cited by Garcia-Diaz et al., 2006). Poor somatic condition during the spawning season is a common observation in many species of fish, and gives an indication that the somatic growth is limited due to the development of gonads. The decrease in condition has been ascribed to a depletion of body reserves during gonad maturation (Salgado-Ugarte, 1995; cited by Pena- Mendoza et al., 2005). This condition was observed in C. orientalis because minimal HSI values were obtained during the reproductive period. For both sexes, when the HSI values were at its minimal, the GSI values were highest and this condition suggesting the point that the liver has a weight loss during reproduction which may indicate the mobilization of hepatic reserves for gonads maturation. Condition factor (K) is one of the most important parameters, which throws light on the physiological state of the fish in relation to indication of the onset of the sexual maturity (Salam and Davies, 1994). The condition factor also showed a minimum value in the spawning season in this work. Moddock and Burton (1999) who interpreted this condition as the result of mobilization of somatic energy reserves needed for reproductive development and energy in spawned fish, influenced by reduced feeding during this period (cited by Palazon-Fernandez et al., 2001). In this study, such correlation was found in both sexes. However, a slight variation of K values for both sexes was shown during study period.

14 60 Universities Research Journal 2011, Vol. 4, No. 2 Ricker (1975) demonstrated that the value of regression coefficient b = 3 indicated that the fish retains the same shape, it grows systematically (or) isometrically which means fish shape doesn't change as fish grows. A value significantly larger or smaller than 3 indicates allometric growth, if b is less than 3 showed that the fish becomes lighter (negative allometric), if b is greater than 3.0, it indicates that the fish becomes heavier (positive allometric) for its length as it increase in size (cited by Salam and Mamood, 1993). The value of b may vary with feeding state, maturing, sex and furthermore different population of a species indicating taxonomic differences in small population (Salam and Davies, 1994). In the present study, regression coefficients (b) of length-weight relationship were significantly higher than 3 in both sexes. Therefore, it is revealed that both male and female showed positive allometric growth. Costa and Araùjo (2003) reported that r value of 0.99 was the highest value associated to the individuals that present highest weight for a given length. In the present work, the values of correlation coefficient were r = 0.93 for male and r = 0.91 for female. Therefore, it is assumed that relationship between length and weight suggesting a good adjustment in growth of male and female. Nikolsky (1963) stated that the sex ratio varies considerably from species to species, but in the majority of cases it is close to one, and may vary from year to year in the same population. In this work, sex ratio was 1 : 0.88 (males to females) representing 54.31% male and 45.69% female, which shows no significant variation from the expected 1:1 (p > 0.05). It is concluded that the reproductive cycle of C. orientalis is divided into prespawning (January February), spawning (March October) and postspawning (November December) periods and the species is a seasonal spawner. Acknowledgements The authors are grateful to Dr. Mie Mie Sein, Professor and Head, Department of Zoology, University of Mandalay, for her suggestions and encouragement, and also to Dr. Naw Dolly Wilbur, Department of Zoology, University of Mandalay, for her encouragement.

15 Universities Research Journal 2011, Vol. 4, No References Arruda, L.M., Azevedo, I.N. and Neto, A.I., Abundance, age structure and growth, and reproduction of gobies in the Riade Avciro Lagoon (Portugal). Estuarinc, Coast and Shelf Sci., 37: Bailey, N.T.J., Statistical methods in biology. The English University Press ltd., London, 200 pp. Costa, M.R.D. and Araùjo, F.G., Length-weight relationship and condition factor of Micropogonias furnieri (Desmarest) (Perciformes, Sciaenidae) in the Sepetiba Bay, Rio de Janeiro State, Brazil. Revista Bras. Zool., 20(4): Cui, U. and Wootton, R.J., Effects of ration, temperature and body size on the body composition, energy content and condition of the minnow, Phexinus phoxinus (L). T. Fish Biol., 32: Garcia-Diaz, M., González, J.A., Lorente, M.J. and Tuset, V.M., Spawing season, maturity sizes and fecundity in Hacktail Comber (Serranus atricauda). Lampert, V.R., Azevedo, M.A. and Fialho, C.B., Reproductive biology of Bryconamericus iheringii (Ostariophysi: Cheracidae) from rio Vacacai. Rs, Brazil. Neotropical Ichthyology, 2(4): LeCren, D.E., The length-weight relationship, seasonal cycle, gonad weight and condition in the perch, Perca fluviatilis. Journal of Animal Ecology, 20: Lucifora, L.O., Menni, R.C. and Escalante, A.H Reproductive ecology and abundance of the sand tiger shark, Carcharias Taurus, from the southwestern Atlantic. ICES Journal of Marine Science, 59(9): Nikolsky, G.V., The ecology of fishes. Academic Press. London and New York. 352 pp. Palazon-Fernandez, J.L., Arias, A.M. and Sarrasquete, C., Aspects of the reproductive biology of the toadfish Holobatrachus didactylus (Schneider, 1801) (Pisces: Batrachoididae). Sci. Mar., 65(2): 13l-138. Pena-Mendoza, B., Geomez- Marquez, J.L., Salgado-Ugarte, L.H. and Ramirez-Noguera, D., Reproductive biology of Oreochromis niloticus (Perciformes: Cichilidae) at Emiliano Zapata Dam, Morelos, Mexico. Kev. Biol. Trop., 53(3-4): Rheman, S., Islam, M.L., Shah, M.M.R., Mondal, S. and Alam, M.I., Observation on the fecundity and gonadosomatic index (GSI) of Grey Mullet Liza parsia (Ham.). Online Journal of Biological Sciences, 2(10): Salam, A. and Mamood, J.A., Weight-length and condition factor relationship of a freshwater under yearling wild Catla catla (Hamilton) from River Chenab (multon). Pakiston Journal of Zoology, 25(2):

16 62 Universities Research Journal 2011, Vol. 4, No. 2 Salam, A. and Davies, P.M.C., Body composition of Northern Pike (Esox Lucius L.) in relation to body size and condition factor. Fisheries Res., 19: Talwar, P.K. and Jhingram, A.G., Inland fishes of India and adjacent countries. Oxford and IBH Publishing Co. PVD. Ltd., Calcutta. Tyler, A.V. and Dunns, R.S., Ration, growth and measures of somatic and organ condition in relation to meal frequency in winter flounder, Pseudopleuronectes americanus, with hypothesis regarding population homeostasis. J. Fish. Res. Biol. Canada, 33: Wingfield, J.C. and Grimm, A.S., Seasonal changes in the plasma cortisol level in Plevronectes platessa L. Gen. Comp. Endocrinol., 31(1): Yeldan, H. and Avsar, D., A preliminary study on the reproduction of the rabbit fish, Siganus rivulatus (Forsskal, 1775) in the Northeastern Mediterranean. Truk. J. Zool., 24: Zafar, M., Mussaddeq, Y., Akhter, S. and Sulton, A., Weight-length and condition factor relationship of Thaila, Catla catla from Rawal Dam Islamabad, Pakistan. Pakistan Journal of Biological Sciences, 6(17):

6. LENGTH -WEIGHT RELATIONSHIP AND CONDITION FACTOR INTRODUCTION Length-weight relationship studies of fishes are considered as an

126 6. LENGTH -WEIGHT RELATIONSHIP AND CONDITION FACTOR 6.1. INTRODUCTION Length-weight relationship studies of fishes are considered as an important tool for understanding of fish. Length is a linear