S. Banik et al/ Journal of Environment (2012), Vol. 01, Issue 02, pp ISSN Research Paper

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1 Research Paper Ompok pabda (Hamilton-Buchanan, 1822): New Reports from Freshwater Environment of Tripura, India with a note on Length Weight Relationship and Condition Factor (K) S. Banik*, P. Goswami, T. Acharjee and Samir Malla Aquaculture Research Unit, Department of Zoology, Tripura University, Suryamaninagar Tripura, India * sukbanik@rediffmail.com Abstract Ompok pabda (Hamilton-Buchanan, 1822) is a valid species. The present observation reports this species for the first time from freshwater environmental resources of Tripura, India. A new distributional record for this species was noticed from Gomoti, Muhuri and Feni rivers of Tripura. The data of the physico-chemical parameters of the studied freshwater environmental resource was highlighted. The length-weight relationship of this fish species was found to be W= L Here regression parameter b ranged from 2.81 to 3.32 (r 2 > 0.90). The relative condition factor fluctuated from with higher value during pre-monsoon. During the pre-monsoon, the allometric coefficient b of the LWR was close to isometric value (b = 3.08) as well as allometric value (b = 2.87). Throughout monsoon period the data suggests negative allometric growth of Ompok pabda. The condition factor ranged from to The feeding intensity was found to be maximum during post-monsoon period. The diet composition indicated the highest ingestion of smaller fish followed by crustaceans as well as death and decayed matter. The present findings may be useful in conservation angle of vision and sustainable fisheries management viewpoints also. Keyword: Ompok pabda, Length-Weight Relationship, Conservation, Isometric, Allometric 1. Introduction Ompok pabda (Hamilton-Buchanan, 1822) is an indigenous and freshwater fish species belonging to the family Siluridae of the order Siluriformes. As a food fish it is delicious due to having larger concentration of lipoprotein and soft bone in them. In India, this species is distributed in the plains and sub mountain regions (Jayaram, 1999; Chakrabarty et al, 2007; Banik et al, 2011 and 2012). However, the natural population of O. pabda is greatly reduced in the Indian water and its restricted occurrence with smaller population size is noticed in north-eastern India (Banik et al, 2012). Ompok pabda (Hamilton-Buchanan, 1822) is a valid species. The native distribution of this species is not sufficiently documented in India. In North-eastern India exact location of this species is not clearly understood. However, it was noticed somewhere in the river ecosystem of Tripura (Banik et al, 2010 and 2011). This species is listed as threatened species as per criteria of conservation assessment and management plan (CAMP, 1998; CAFF, 2006 and Lakra et al, 2010). Once upon a time relatively greater density of Ompok pabda was recorded in the river Gomoti, Muhuri and Feni of Tripura, India. Probably for this reason, these rivers were also known as resource of rich diversity of freshwater fishes (Banik et al, 2010). Due to the deficiency of information on the biological aspects of the threatened fishes, the planning and implementation of species-specific conservation and Available online at 40

2 management strategies could not be adopted till-date. Therefore, knowledge of length-weight data (LWR) is most useful in fisheries science (Le Cren, 1951). Information of Ompok as a genus and Ompok pabda as a species is poor (Sarkar et al, 2005; 2008; 2010; Banik et al, 2011 and 2012). The present study reports Ompok pabda for the first time from Tripura, North-eastern India. This study communicates first reference on morphometric aspects of the species such as condition factor as well as lengthweight relationship (LWR) and feeding habit. 2. Materials and Methods Altogether a total of 327 individuals of Ompok pabda were sampled from the River Gomoti, Muhuri and Feni of Tripura between February, 2009 to March, Climate of the study area is defined by dry season from November- March and wet season from April-October. The collected samples were brought to the Aquaculture Research Unit, Department of Zoology, Tripura University, India for detailed studies. The samples were firstly cleaned with isopropanol (5%) and measured to the nearest 0.1 cm (total length) and weighed to the nearest 0.1 gm using electronic balance. For observations of length-weight relationship and relative condition factor the mathematical equation (Le Cren, 1951) was used in estimating LWRs: W= a L b Where: W: Total Body Weight (g) L: Total Length (cm) a and b are the Coefficients of the Functional Regression Between W and L An allometric coefficient b value which may be equal to/ greater or smaller than 3.0 will show either allometric or isometric growth (Bagenal & Tesch 1978). In order to confirm whether the b value obtained in the linear regression was significantly different from the isometric value (b = 3), t-tests for independent samples were used for this purpose. The value of constant a and b were estimated from the log transformed values of length and weight, i.e.: logw = loga + b logl via least square linear regression. The degree of association between the variables was computed by the determination coefficient, r 2. The condition factor K was estimated from the length-weight relationship. Statistical analysis was done through SPSS package version. In order to understand the environmental features of the studied river ecosystem of Tripura the data of physico-chemical parameters of different freshwater river ecosystem was analysed following standard methodology (AHA, 2004) 3. Results Total length of the sampled fish varied from cm (22 g) to 31.0 cm ( g). Of the studied data the female individuals of Ompok pabda have had relatively greater weight. The total length of the males varied from cm to cm, while in females this value was ranged from 17.0 cm to 33.0 cm. Interestingly, the density of the female was dominated over male during all the sampled population. Significant correlation exists between the length and weight parameter in both male (r = 0.943) and female (r = 0.827). The relative condition factor (K) in female remained high in size groups cm and then gradual decline to the size group cm was noticed. While in male relative condition factor (K) remained low in the size group cm and then sudden increase to the size group cm was recorded. The data of the physico-chemical parameters of the studied freshwater river ecosystem was presented in Table 1 and Figure 1. Regression equations for male and female fish were presented in Figures 2-3. Table 1. Water Quality Features of the Different Water Bodies of Tripura S. No. Parameter Range 1 Water Temperature 29± 2.2 o C 2 ph 7.5± Dissolved Oxygen 7.0± 2.32 ppm 4 Free CO 2 4.3±2.12 ppm 5 Turbidity 2.5±1.1 cm 6 Water velocity ±0.37 m/sec 7 Bicarbonate 120±27.10 ppm 8 Nitrate Less than 0.01 ppm 9 Phosphate Less than ppm 4. Discussion The present study reports Ompok pabda (Hamilton- Buchanan, 1822) for the first time from freshwater environmental resources of Tripura, India. It is a valid species. A new distributional record for this species was noticed from some freshwater river ecosystems of Tripura such as Gomoti, Muhuri and Feni as well (Banik et al, 2011 and 2012). In the present observation the parameter b ranged from 2.74 to 3.42 and showed distinct seasonal differentiation. The value b during pre-monsoon period was 3.06 (near to Available online at 41

3 3) and so showed isometric growth. In the monsoon and post-monsoon periods the value b varied slightly, indicating allometric growth. Froese (2006) pointed out that when b = 3 the growth pattern is isometric and the result is noticed during the pre-monsoon period (r=0.9). Hence, it may be due to the same body form and conditions and also because of quite narrow size range of the studied length parameter. Figure 1. The Characteristic Feature of Rainfall in the Site of Study in Tripura, India Figure 2. Regression Curve Showing the Relationship Between Length and Weight in Male Ompok pabda b value of less than 3 noticed during monsoon period indicating a smaller size of the studied specimen. So, this data shows that they are in greater population size (Savikami, 1987). Fluctuations in b value from 3.0 during the monsoon and post-monsoon periods revealed that the length-weight relationship in this species followed the cube law and might be affected by the general condition of appetite and gonadal contents. These factors are also responsible for the variations in condition factor. The b- value of overall length-weight relation was 2.87, showing allometric growth. This value is quite different from the other closely related species of this genus, Ompok. b = 3.0 (isometric growth) as reported by Sani et al (2010) from same river and the findings of Sivakami (1987) from a reservoir of India are in line with the present observation. LWR parameter of this fish species is affected by a series of factors including season, habitat, gonad maturity, sex, diet, stomach fullness, health, and preservation techniques (Tesch, 1971 and Bagenal & Tesch, 1978). A similar mode of variation in the length-weight relationship in male and female M. vittatus was also reported by Hossain (2006). All allometric coefficients (b) estimated in this study were within the expected range of All linear regressions of length-weight relationships were highly significant (P < 0.001), with r value =0.992, p< The condition factor (K) is an index reflecting interactions between biotic and abiotic factors in the physiological condition of the fishes. It shows the well-being of the population during various life cycle stages (Angelescu et al, 1958). Average value of Fulton s condition factor (K) for this species in different seasons ranged from 0.62 to There were significant differences (P < 0.001) in K values of O. pabda among seasons. The higher value of K during the premonsoon season indicates that the population of this fish species in young stage is available during this season. This may be due to differences in the state of maturity and availability of fish food organisms in the Riverine Ecosystem. This species spawns in June to July (Hussain, 2006; Chakrabarti et al, 2009; Banik et al, 2011 and 2012) and the low value of K during monsoon season indicates that the fish population size at this season is low. Heincke (1908) also described the seasonal variation of K in the south-eastern North Sea area and found that the better the nutritional condition, the higher the K, which is in line with our observation. Figure 3. Regression Curve Showing the Relationship between Length and Weight in Female Ompok pabda Therefore, this study adds some knowledge on new reports of this species with a note on some basic information on L-W relationships and the condition factor which may be useful in fisheries biology view point and also in the conservation point of views. Available online at 42

4 Acknowledgements One of the authors (SB) thankfully acknowledge DBT (Sanction no. BT/16/NE/TBP/2010, dated 17/01/2011 under DBT s Twinning Programme) for financial support. Thanks are due to the Head, Department of Zoology, Tripura University (Central University) for providing laboratory facilities. Kind cooperation extended by Dr Abir Shib, Research Associate, Bioinformatics Centre, Tripura University in providing various statistical analysis and Sri Kshitish Ch. Das, progressive fish farmer at Udaipur, Tripura, is gratefully acknowledged. References Angelescu, V., Gneri, F.S., and Nani, A. (1958) La Merluza Del Mar Argentine (Biologia Y Taxonomia). Buenos Aires, Secretaria de Marina, Servicio de Hidrografia Naval Publico. Bagenal, T.B., and Tesch, F.W. (1978) Age and growth. In: Begenal, T. ed. Methods for Assessment of Fish Production in Fresh Waters. 3rd ed. IBP Handbook No. 3, Oxford, Blackwell Science Publications, pp Banik, S., and Malla, S. (2009) Rotifer as a growth promoter for a rare fish Ompok bimaculatus related to climate change. Proceedings of Workshop on Aquaculture Biotechnology for Women for Rural Development. Tripura University, pp Banik, S. (2010a) Improvement of Reproductive Performance and Larval Rearing of an Endangered Fish Species of Northeast, Ompok Bimaculatus (Pabda) Through Nutritional Approaches Technical Report-I. New Delhi, DST. Banik, S. (2010b) Biology, Population Genetics and Captive Breeding of Ompok Bimaculatus from Tripura: A State Fish for Conservation: Technical Report. Lucknow, NBFGR. Banik, S. (2011) Improvement of Reproductive Performance and Larval Rearing of an Endangered Fish Species of Northeast, Ompok Bimaculatus (Pabda) Through Nutritional ApproachesP: Technical Report- II. New Delhi, DST. Banik, S., Goswami, P., and Malla, S. (2011) Ex-Situ Studies of Captive Breeding of Ompok bimaculatus (Bloch, 1794) in Tripura. J. Adv. Lab. Res. Bio., 2(3), pp Banik, S., Goswami, P. and Malla, S. (2012) Studies on breeding physiology of Ompok bimaculatus (Bloch, 1794) in Tripura. U.P. Journal of Zoology, 32(1), pp Workshop on Conservation Assessment of Freshwater Fish Diversity (CAFF) for Central India, Bhopal, (2006) Proceedings of the Workshop on Conservation Assessment of Freshwater Fish Diversity (CAFF) for Central India. Lucknow, National Bureau of Fish Genetic Resources (NBFGR). Workshop on Conservation Assessment and Management Plan (CAMP) for freshwater fishes of India, 1998, Lucknow (1998). Proceedings of the Workshop on Conservation Assessment and Management Plan (CAMP) for freshwater fishes of India. Lucknow, NBFGR and Zoo Outreach Organization, pp Chakrabarti, P.P., Chakrabarty, N.M., and Mondal, S.C. (2009) Breeding and Seed Production of Butter Catfish, Ompok pabda (Siluridae) at Kalyani Centre of CIFA, India. In: Chakrabarti, P.P., Chakrabarty, N.M., and Mondal, S.C. eds. vol. 14. Research and Farming Techniques. Aquaculture Asia Magazine, pp Froese, R. (2006) Cube law, condition factor and weightlength relationships: history, meta-analysis and recommendations. J. Appl. Ichthyol., 22, pp Fulton, T.W. (1904) The Rate of Growth of Fishes: 22nd Annual Report, Part III. Edinburgh, Fisheries Board of Scotland, pp Heincke, F. (1908) Bericht u ber die Untersuchungen der Biologischen Anstalt auf Helgoland zur Naturgeschichte der Nutzfische. (1 April Oktober 1907). In: Die Beteiligung Deutschlands an der Internationalen Meeresforschung, 4 & 5. Jahresbericht. Berlin, Verlag von Otto Salle, pp Hossain, M.Y., Ahmed, Z.F., Leunda, P.M., Jasmine, S., Oscoz, J., Miranda, R., and Ohtomi, J. (2006) Condition, length-weight and length-length relationships of the Asian striped catfish Mystus vittatus (Bloch, 1794) (Siluriformes: Bagridae) in the Mathabhanga River, South-Western Bangladesh. J. Appl. Ichthyol., 22, pp Hussain, A. (2006) Seed production of Ompok pabda (Ham.) in hatchery of C.G. Co-operative Fish Federation. Fishing Chimes, 26, pp Jayaram, K.C. (1999) The Freshwater Fishes of the Indian Region. New Delhi, Narendra Publication House, p Lakra, W.S., Sarkar, U.K., Gopalakrishnan, A., and Pandian, A.K. (2010) Threatened Freshwater Fishes of India. Lucknow, National Bureau of Fish Genetic Resources (NBFGR) Publication. Available online at 43

5 Le Cren, E.D. (1951) The length-weight relationship and seasonal cycle in gonad weight and condition in the perch (Perca fluviatilis). J. Anim. Ecol., 20, pp Sani, R., Gupta, B.K., Sarkar, U. K., Pandey, A., Dubey, V.K., and Lakra, W.S. (2010) Length weight relationships of 14 Indian freshwater fish species from the Betwa (Yamuna River tributary) and Gomti (Ganga River tributary) rivers. J. Appl. Ichthyol., 26, pp Sarkar, U.K., Deepa, P.K., Negi, R.S., Poul, S.K., and Siongh, S.K. (2005) Captive breeding of an endangered fish Ompok pabda (Hamilton-Buchanan) using different doses of ovaprim. J. Inland Fish. Soc. India, 37, pp Sarkar, U.K., Pathak, A.K., and Lakra, W.S. (2008) Conservation of freshwater fish resources of India: new approaches, assessment and challenges. Biodivers. Conserv., 17, pp Sarkar, U.K., Gupta, B.K., and Lakra, W.S. (2010) Biodiversity, ecohydrology, threat status and conservation priority of the freshwater fishes of River Gomti, a tributary of river Ganga (India). Environmentalist, 30, pp Sivakami, S. (1987) Length-weight relationship and relative condition in Ompok bimaculatus (Bloch) from Bhavanisagar Reservoir (Tamil Nadu). Indian J. Fish., 34, pp Tesch, F.W. (1971) Age and growth. In: Ricker, W.E. ed. Methods for Assessment of Fish Production in Fresh Waters. Oxford, Blackwell Scientific Publications, pp Available online at 44