Estelar CHAPTER IV FECUNDITY AND SEX-RATIO

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1 CHAPTER IV FECUNDITY AND SEX-RATIO

2 4.1 - INTRODUCTION Fecundity is generally defined as the number of ova that are likely to be laid by a fish during its spawning season. It depends on several factors such as age, size of fish, rainfall, and salinity of water and may differ in different races of the same species (Khanna and Singh, 2003) [165]. This reproduction power is an essential aspect of fish biology, which must be understood to explain the variation of the level of population as well as to make efforts to increase the amount of fish harvest. The information on the fecundity is an imperative part of the fish biology, which is useful in several applied aspects of fishery science, including fishery management of any water bodies. Lagler et. al., in 1967 [166] opined that the fecundity appears to have some broad relationship with the care of environment accorded to the eggs. This work considered only the ripe spawnable eggs in the ovary. Fecundity must be known to assess the productivity potential and to evaluate the commercial potentiality of a fish stock. A lot of researches were carried out for the fecundity estimation on a number of fishes such as Clarias lazera by Nawar and Yoakin (1962) [167], Tilapia mossambica by Riedel (1965) [168], Tor putitora by Pathani (1981) [169], Puntius chilinoides by Singh (1982) [170], Puntius stigma by Islam and Hossain (1990) [171], Puntius sarana by Kumar and Siddique (1991) [172], Puntius sophore by Bhuiyan and Parveen (1998) [173], Crossocheilus latius latius by Dobriyal et.al. (2003) [174], Chela untrahi by Kiran and Puttaiah (2003) [175], Labeo Coubie by Ikpi and Okey (2010) [176], Pseudecheneis sulcatus by Bahuguna and Kumar (2011) [177], etc. A prior knowledge of sex ratio fishes is essential for the management practices of fishery science. It is important to ensure a proportional fishing of two sexes. Sex population

3 estimation is defined the abundance of any sex at a particular time or the population in natural condition. It is generally known that in a healthy population, the sex ratio should be 1:1. There are several other factors such as temperature, water velocity, and vulnerability of females to their predators, migratory phase and other ecological hazards, which probably change the sex composition in streams or rivers (Jameela Beevi and Ramachandran, 2005) [178]. The studies on the sex ratio of different kind of fishes were explored very recently. The sex ratio of Macrones bleekeri by Panwar and Mani (2006) [179], of Cirrhina reba by Shendge and Mani (2009) [180], of Labeo dyocheilus by Verma and Shah (2011) [181] have been studied. Along with the sex ratio, fecundity was also studied by some researchers. Kumar et. al, (2006) [182] studied on the fecundity and the sex ratio in a rare hill-stream fish Botia dayi Hora. Bahuguna et. al, (2009, 10a,b) [183] [184] [185] worked on breeding power and sex ratio in Garra lamta and the reproduction capacity and sex ratio in Noemacheilus denisoni respectively. Some researches were carried out on the sex ratio along with the reproductive biology of fishes. Gaigher (1983) [186] focused on reproduction of Labeo umbratus. Sobhana and Nair (1976) [187] studied on the maturation and spawning of Puntius sarana subnasutus. Van (1995) [188], Pathani (2000) [189] and Montchowui (2010) [190] discussed the reproduction biology of Labeo capensis, Tor putitora and Labeo senegalensis Valenciennes respectively. Present study deals with the fecundity and the population sex ratio status of Labeo dyocheilus in Western Ramganga. It is for the first time this species (Labeo dyocheilus) is being studied in Kumaun Hills especially in Western Ramganga MATERIAL AND METHODS

4 The study of fecundity and sex ratio comprises two major divisions: estimation of fecundity and estimation of sex ratio. The collection of fish samples were carried out at Western Ramganga River from Kumaun hills for a period of two years during September 2009 to August The geographical location of the sampling area is Latitude: 29 53' 55" North and Longitude: 79 21' 22" East. 1. Estimation of Fecundity: In the present study, only mature female are considered to estimate fecundity of Labeo dyocheilus. Total length (cm) and weight (g) of the examined fish samples were recorded. After gross examination, ovaries were preserved by 4 % formalin. Fecundity estimation was done by gravimetric count method. For this three samples of 100 mg each were taken at random from anterior, middle and posterior portions of each ovary. The number of ova in each sample was counted under the binocular microscope and the fecundity was calculated by following formula: 100 Where, F = Fecundity, S = Average number of egg samples (100 mg each), OW = Total weight of ovary. After the estimation of fecundity, it is correlated with body length, body weight, ovary length and ovary weight by plotting fecundity data against each of these parameters. The best

5 fit value was obtained by fitting the plot in a straight line with the help of following equation of straight line: Y = a + bx Where, x = Independent variable (e.g. fish length, fish weight, ovary length and ovary weight) Y = Dependent variable e.g. fecundity b = Slop of the straight line a = Intercept of the line on Y-axis 2. Estimation of sex ratio: For estimation of sex ratio, the fish specimens were preserved in 5 % formalin. The total length and weight of fish was measured in fresh condition. However, the other parameters were measured within a fortnight of collection. To study the sex ratio of the Labeo dyocheilus in western Ramganga river total of 202 specimens were collected (129 males and 73 females). Sex-ratio was calculated for entire study period of two years and its significance was tested by Chi-square test (χ²) RESULTS 1. Estimation of Fecundity: The estimation of fecundity of Labeo dyocheilus was done by observing the fishes of different size groups, as shown in table 4.1. The shortest length fish observed in the sample was of 10.3

6 cm and the largest length was of 29.8 cm. In the samples, 130 g was observed to be minimum fish weight and 596 g to be maximum fish weight. The ovary length of the collected samples was varied from 2.5 cm to a maximum value of 11.4 cm. The ovary weight observed was to be varied from 20.1 g to g. Fecundity of the fish samples was calculated with the help of the formula mentioned in the method of estimation of fecundity, which varied from a minimum of 2170 to a maximum of In the present work, we have made 4 different size groups of fishes viz to 15.0 cm, 15.1 to 20.0 cm, 20.1 to 25.0 cm and 25.1 to 30.0 cm. It is clear from figure 4.1, 4.2, 4.3 and 4.4 that fecundity of fish increases linearly with fish length (FL), fish weight (FW), ovary length (OL) and ovary weight (OW). The linear relationship is obvious from the equation of straight line. We can see that, FW (R 2 = 0.943) as well as OW (R 2 = 0.933) are more responsible to increase the fecundity in compare to FL (R 2 = 0.893) or OL (R 2 = 0.876). Moreover, fish weight appears to be slightly more responsible for fecundity increment as compare to ovary weight. 2. Estimation of sex ratio: For determination of sex ratio, fishes of length 10.3 to 29.8 cm were selected during the study. The monthly variation in the population sex-ratio of Labeo dyocheilus is shown in table 4.2 and Fig The table shows that the ratio of male: female is highest in August and equals to 2.33: The ratio of male: female was found to be lowest in two months viz. September and July with the value of 1.40: Corresponding to the month wise ratio of male and female fishes, Chi-square (χ²) was calculated. We observed that the estimation of sex population both in male and female showed non-significantly at 5 % level of significance in

7 various months. In the month of May there was significant difference in the ratio of male and female fish with the value of 2.17 male: 1.00 female. The seasonal and pooled data indicating variations in the sex ratio of Labeo dyocheilus are presented in Table 4.3 and Fig It was observed that summer season is the peak season for male: female (2.09: 1.00). The ratio of male: female was found to be lowest in spring season (1.54: 1.00). The total pooled data were computed to show the average sex population status of 1.77 male: 1.00 female in Labeo dyocheilus during the course of study. Similar to monthly variation, the estimation of sex population both in male and female showed nonsignificantly at 5 % level of significance in various seasons. The season summer (2.09 M: 1.00 F) and overall sex ratio from pooled data (1.77 M: 1.00 F) illustrated significantly at 5 % level of significance DISCUSSION In the present study, we observed that the breeding capacity or fecundity of Labeo dyocheilus of length and weight varies from 2170 to 22,919. Similar study had been done by Bhatnagar (1964) [191] who observed a range of breeding potential from 67,288 to 3,10,934 for Labeo dero with the length of 33 to 50 cm. Joshi and Khanna (1980) [192] reported range of fecundity from 47,168 to 3,80,714 for Labeo gonius from Nanaksagar reservoir. Vijay Kumar (1986) [193] observed the range of fecundity from 1800 to 12,932 in Puntius filamentus measuring 62 mm to 112 mm from vellayani lake (Trivendrum). Dhasmana (1990) [194] observed the fecundity of Garra gotyla gotyla from 1,05,900 to 1,94,349 in the fish measuring from 15.2 to 19.2 cm in river Alaknanka. Bhatt and Pathak (1992) [195] advocated that the maximum fecundity of golden Mahseer was 1,22,325 in Saryu river of Kumaun.

8 According to Desai (2000) [196] the fecundity of Tor tor from river Narmada was 7,000 to 1,01,600 in the fish measuring 28 to 75 cm. Narejo et. al. (2002) [197] found the maximum fecundity 10,980 in a fish measuring 605 mm in the total length and minimum fecundity 580 was observed in fish having a total length of 245 mm in Mastacembelus armatus (fresh water eel ). According to Dobriyal et. al. (2003) [198], the fecundity of Crossochcilus latius latius had a range of 20,660 to 70,630 in the fish measuring 16.0 to 26.3 cm from river Mandakini of Garhwal, Uttarakhand. Mahapatera, et. al. (2004) [199] studied the fecundity of Zebra danio, Braghydanio rerio in range of 215 to 4004 in the fish measuring 29 to 81 mm from Meghalaya, North Eastern Indian. Kumar et. al. (2006) [200] observed low breeding potential of Botia dayi Hora in a range of 2,225 to 8,840 for the fish measuring 10.1 to 14.5 cm and weighing g to 38.6 g. The breeding capacity of Barilius vagra was estimated from Garhwal region in a range of 510 to 7214 in the fish measuring 55 mm to 89 mm and ovary weighing from 407 mg to 4,260 mg by Bahuguna et. al. (2009) [183]. It is concluded from our study that fecundity of the collected fish specimens is increased with an increase in all the body parameters such as fish length, fish weight, ovary length and ovary weight. The straight-line relationship was observed between fecundity and above body parameters. These results are also supported by Sharma (1984) [201] and Agarwal (1988) [202]. According to Sharma (1984) [201] the breeding capacity of G. pectinopetrus was found to be directly proportional to the length-weight of the fish and weight to the ovary. Agarwal et. al., (1988) [202] noticed in Noemacheilus montanus that the breeding potential consistently increased with an increase body parameters and straight line relationship was noticed in all the cases.

9 In the study of estimation of fecundity, we noticed that fish weight (R 2 = 0.943) as well as ovary weight (R 2 = 0.933) are more responsible to increase the fecundity in compare to fish length (R 2 = 0.893) or ovary length (R 2 = 0.876). Moreover, fish weight was observed to be more responsible for fecundity increment compare to ovary weight. Similar results were reported by Shafi and Quddus (1974) [203] and concluded that the correlation of fecundity with gonad weight is more significant compare to that of fecundity with others body parameters for the fresh water fish Puntius stigma. Bahuguna and Kumar (2011) [177] also reported that the total breeding capacity of Pseudecheneis sulcatus was recorded as 781 to 8,314 in the fish ranging from 10.0 cm to 23.9 cm and has been observed that the breeding capacity was highly dependent on fish weight (0.9967) and ovary weight (0.9696) than any other body parameters. Sunder (1984) [204] observed that the fecundity of S. langipinnis was more or less equally related to the length and weight of fish. In the estimation of sex ratio from the polled data, we concluded that the proportion of male to female is 1.77: 1.00 for L.dyocheilus collected from the Western Ramganga River. We also observed that the month wise as well as seasonal variation male female population is not similar throughout the year. These observations are similar to the study of Chacko and Ganapati, 1982 [205] who stated that in different periods of the year in the various size-groups and thus we can get information about the abundance of the sex at a particular time or throughout the year. Holcik et.al, (1988) [206] stated theoretically, the expected composition of males to females is 1:1. Nasar and Biswas (1987) [207] reported the sex ratio of Puntius clavatus, in which male and female ratio was 1:1. Islam and Hossain (1990) [171] showed a 1:1 sex composition in Puntius stigma.

10 It was observe in the present study that the male population is dominated over the female population for month wise as well as seasonal distribution. Similar to our study, Olatunde in 1978 [208] stated that: in natural environment the optimum sex composition is 1:1, but it may be for a particular age and size group. The sex ratio (1.00: 0.40) in favour of males, with few exceptions of female dominance, is a deviation from the Kainji Lake population of 1.00: 4.20 in favour of females. However, he also reported few exceptional cases of male dominance. Ikusemiju and Awobamise (1981) [209] also observed changes from female to male dominance. The sex composition of Barilius vagra noticed was 1.29 Male: 1 Female from Mandal River in Garhwal region by Bahuguna et. al, (2009) [183]. Female dominance has been observed in several studies. The sex-composition of Labeo cylindricus was found female dominated at 1 male: 1.63 females in the Lake of Chicamba, a hydroelectric dam in central Mozambique, South Africa by Wely and Booth (1999) [210]. The sex ratio of Puntius vittatus was 1 male: 2 female reported by Jameela Beevi and Ramachandran (2005) [178] from Ernakulam district (Kerala). The male: female ratio was 1:1.15 in Cirrihina reba calculated by Shendge and Mani (2009) [180]. Bahuguna et. al, (2007) [211] calculated that the sex composition was quite natural in Puntius conchonius (1 Male: 1.17 Female) from Mandal river. The male and female ratio was 1: 1.15 in Cirrihina reba from Bhima River, near Bhigwan, Pune District, Maharashtra reported by Shendge and Mani (2009) [180]. Bahuguna et.al, (2010) [184] reported the sex composition of Garra lamta 1 Male: 1.06 Female in the spring fed water body of Pithoragarh district in Uttarakhand state. In the present work we have reported that the estimation of the sex composition in both male and female showed non-significantly at 5% level of significance in the months and season. While in the month of May there was significant difference in the sex ratio of male

11 and female fish (2.17 male: 1.00 female). In the summer season (2.09 M: 1.00 F) and overall sex ratio from pooled data (1.77 M: 1.00 F) showed significantly at 5 % level of significance. From the present work and on the basis of earlier observation it is concluded that the sex population of the major carp, L.dyocheilus (Mc.Cl.), from almost all the localities male fishes are dominated. During the overall investigation on the Labeo dyocheilus, the sex ratio was observed significant (1.77 male: 1.00 female). The chi-square value also showed 3.84 which are significant at 5 % level. Nikolsky (1956, 80) [212] [213] suggested that the optimum sex ratio may vary drastically by numerous factors and it may also depend on different populations inhabiting in different regions CONCLUSIONS In summary, we have observed a fecundity range of fish specimen having various lengths and weights. We were successfully correlated fecundity of fish with fish length, fish weight, ovary length or ovary weight and found that increase in the fecundity is much more influenced by fish weight and ovary weight than fish length and ovary length. A linear relation was found between fecundity and these body parameters. We have observed a high-quality fecundity range for Labeo dyocheilus, which is a good breeding capacity for fish culture. In the estimation of sex ratio, we have concluded that the population sex ratio is different in different months throughout the year. It is also concluded that the sex ratio is significant at 5 % level of significance in the month of May and summer season but non-significant in rest of the months and seasons. Table Estimation of fecundity of Labeo dyocheilus

12 Class Interval FL (cm) FW (g) OL (cm) OW (g) Fecundity ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±4208 From the data mentioned in the above table; plot between fecundity versus fish length (Fig. 4.1), fecundity versus fish weight (Fig. 4.2), fecundity versus ovary length (Fig. 4.3) and fecundity versus ovary weight (Fig. 4.4) drawn.

13 Fig Correlation between fecundity and fish length (cm) Fig Correlation between fecundity and fish weight (g)

14 Fig Correlation between fecundity and ovary length (cm) Fig Correlation between fecundity and ovary weight (g)

15 Month Table Month wise variation in the sex ratio of Labeo dyocheilus Total No. of fish Male Female % of Male % of Female M Ratio F χ² Remark Sep NS Oct NS Nov NS Dec NS Jan NS Feb NS Mar NS Apr NS May S* Jun NS Jul NS Aug NS χ² = Values are not significant at either level (d.f.1.on p= 0.05 in 3.84); M=Male, F=Female, S* = Significant, NS = Non significant

16 Table Season wise and pooled variation in sex ratio of Labeo dyocheilus Season Total no. of fishes M F % of M % of F M Ratio F Χ² Remark Autumn NS (Sep Nov) Winter NS (Dec Feb) Spring NS (May Apr) Summer (May Jun) Monsoon (Jul -Aug) Pooled Data S* NS S* χ²= Values are not significant at either level (d.f.1.on p= 0.05 in 3.84); M=Male, F=Female, NS= Non significant

17 Fig Month wise sex ratio variation in Labeo dyocheilus Fig Season wise variation in sex ratio of Labeo dyocheilus

Sex ratio of Noemacheilus montanus (Mcclelland) from Pithoragarh district, Uttarakhand, India

ISSN: 2319-7706 Volume 3 Number 12 (2014) pp. 761-767 http://www.ijcmas.com Original Research Article Sex ratio of Noemacheilus montanus (Mcclelland) from Pithoragarh district, Uttarakhand, India Anita