Indian J. Fish., 52(1) : 73-79, Jan.-Mar., 2005 73

Biology of chapra (Hamilton-Buchanan) from a floodplain wetland in West Bengal

G. K. VINCI, V. R. SURESH AND M. K. BANDYOPADHYAYA Central Inland Fisheries Research Institute, Barrackpore, Kolkata-700 120, West Bengal

ABSTRACT Biology of Gudusia chapra (Hamilton-Buchanan) from a floodplain wetland in West Bengal has been studied during 1999-2001. The fish is an omnivore, feeding mainly on Myxophyceae followed by Bacillariophyceae, Turbellaria and Rotifera. November to March was the most active feeding period. The length weight relationship established for the fish suggested fairly isometric growth, closely following cube low. The regression equation obtained was Log W = 2.8576 Log L – 4.7564 (R2 = 0.9176). Fecundity of the fish ranged from 936 to 13,860. The ova diameter ranged from 0.05 to 1.28 mm. The fish has a prolonged breeding season, extending from March to October, during which it releases eggs in batches. The relative condition factor showed well being of the fish.

Introduction clearing and eradicating weed fishes. As a result of this, drastic shift in favour of Floodplain wetlands are integral major carps at the cost of some of the parts of Ganga and prized native fish fauna has been noticed basins. They are formed by river course in beels under culture based fishery changes, leaving behind water bodies management (Sugunan et. al, 2000). with or without connection to the parent rivers. West Bengal has more than 150 Gudusia chapra (Hamilton– such wetlands, locally called beels, Buchanan), belonging to the family spread over an estimated area of 42000 is a delicious, native ha forming 22% of the total freshwater of the beels and fetch good market price area of the state. These beels harbour (Rs. 50-100 per kg) in West Bengal, large number of native fish species and Orissa and the northeast. It has now play a significant role in the inland fish become rare in many of the beels in the production of the state. Fishery of most state. As part of management of of these beels is under management by floodplain wetlands, the Central Inland cooperative societies. The societies Fisheries Research Institute has undertake stocking of the beels (Indian initiated efforts to rehabilitate and major carps), liming, macrophyte restore the stock of important native G. K. Vinci et al. 74 fishes, in selected beels. G. chapra is one among the target species of this by allotting points. For evaluating the programme in West Bengal. Studies on importance of these food items or G. chapra dates back to Kapoor (1954, preference, their index of preponderance 1957). Jhingran (1966) studied the was worked out following Natarajan and biology and fisheries of the fish in the Jhingran (1961). Monthly variations in River Ganga; length weight relationship feeding index were obtained on the basis and condition factor (Jhingran, 1968) of fullness of stomach as suggested by and diet composition (Jhingran 1973). Kow (1950) to assess the feeding Chonder (1973, 1975, 1977) attempted intensity. racial separation of G. chapra from Fish with heavy and medium stomach Keetham and Ganga rivers using various Feeding index = ———————————— x 100 biological parameters of the fish. Length Number of fish examined weight relation and condition factor of the fish in Assam has been studied by Length weight relationship Devashish (2000). Sarkar et al. (2002) The relation between length and reported growth of the fish in water weight common to males and females of bodies of Uttar Pradesh. Nevertheless, the fish was established following the information on the food habits, length formula of Le Cren (1951) by weight relation and reproductive biology transforming into a straight line of the species in beels, which is a equation, log W = log a + b log L. The prerequisite in the stock restoration regression slop was calculated by the programmes, is lacking. Therefore this formula of Lagler (1952). work has been taken up during 1999- 2001 in Garapota beel, situated at Reproductive biology Bongaon, 24 Parganas North district of The sex and stage of maturity of the West Bengal. fishes were identified while dissecting. Materials and methods The ovaries were removed and classified into different maturity stages on the Fish samples were collected at basis of morphological observations monthly basis from Garapota beel, following Lovern and Wood (1937). After through local fishers. After blotting off weighing, the ovaries were preserved in water, their total length and weight were 5% formalin. The fecundity was measured. The size of the fish ranged estimated as described by Grimes and from 96 to 130 mm in length and 4.8 to Huntsman (1980) by counting the 23.91 g in weight. number of mature ova from a known Food habits weight of sub sample of ovary (only V – VI stages) and calculating the total Gut contents of a total of 200 number of ova using the following specimens were were dissected out, formula weighed and preserved in 5% formalin. The gut contents were analyzed through Weight of ovary quantitative and qualitative methods Fecundity = —————————— x No. of mature ova (Hynes, 1950; Pillay, 1952). The food in sample items were identified up to major Weight of sample taxonomic groups. Since the items were The spawning periodicity was very small, their volume was estimated studied by observing the growth of ova Biology of Gudusia chapra 75

by following their diameter progression. (Hickling and Rutenberg, 1936). Eggs were sampled from the middle of the ovary. An ocular micrometer was used for the measurement. The gonado somatic index (GSI) was estimated following June (1953) and expressed as Fig. 1. Monthly variations in feeding inten- the ratio of the weight of gonad to body sity of G. chapra weight in percentage, to understand the spawning season. rest was zooplankton. Algae followed by Turbellaria and rotifera dominated Weight of gonad in the stomach contents. The food GSI = ——————————— x 100 consisted mainly of algae, rotifers, Weight of fish crustaceans, plant matters and Relative condition factor (Kn) of miscellaneous items. Grading the gut female fishes were studied on monthly contents of fishes give indications of basis following Le Cren (1951). Males their food preference (Natarajan and were not subjected for this study. Jhingran 1961). The index of preponderance and preference ranking Results and discussion of food items in the gut showed that Food habit Myxophyceae followed by Bacillariophyceae, Turbellaria and The alimentary canal of G. chapra Rotifera were the preferred food items is short, muscular and less coiled. in the decreasing order of preference Phytoplankton and other plant matter 150 (Table 1). Although, algae were the 100 formed 66.4% of the gut contents and the most preferred food item the available

(%) 50 0 TABLE 1. Index of preponderance (Ii = ViOi / ∑ViOi X 100) of different food items in the gut Feeding intensity AM J J A SONDof J G. FM chapra and their preference ranking Months Food items Vi Oi ViOi Index Rank Bacillariophyceae 13.50 10.80 145.80 15.96 2 Myxophyceae 32.70 10.80 353.16 38.68 1 Microsporaceae 1.88 2.70 5.07 0.55 12 Hydrodictyaceae 0.58 5.40 3.13 0.34 14 Zygnemataceae 4.91 6.70 32.89 3.63 6 Tribonemataceae 0.39 2.70 1.05 0.11 15 Scendesmaceae 1.14 6.70 7.63 0.84 7 Chaetophoraceae 2.75 2.70 7.42 0.81 8 Volvocaceae 8.53 8.10 69.09 7.56 5 Euglenaceae 2.00 6.70 13.40 1.47 10 Desmidiaceae 0.08 2.70 0.21 0.02 16 Turbellaria 15.02 9.40 141.18 15.45 3 Rotifera 11.83 9.40 111.20 12.17 4 Copepoda 0.71 5.40 3.83 0.42 13 Cladocera 2.24 5.40 12.09 1.32 11 Nauplii 1.61 4.00 6.44 0.70 9 Plant matter 0.13 0.40 0.05 0.005 17 ∑ 100 100 913.64 100 — G. K. Vinci et al. 76 data suggested that the fish is an value may change with locality, sex, and omnivore, feeding on zooplankton as maturity (Le Cren, 1951) besides well. Decaying organic matter of plant environmental conditions. Under these origin was also observed in the gut. circumstances the value other than “3” Fishes of all sizes showed almost the indicated allometric growth. According same food preference. to Hile (1936) the values usually fluctuate between 2.5 and 4.0 and in The feeding intensity monitored majority of cases the value was not equal monthly showed that the most active to “3”. Devashish (2000) reported that the feeding period was November to March. cube law held good (n=3.0798) for the April to June was the period of less active species from a floodplain wetland in feeding and July to October was the Assam. Although G.chapra from period of low feeding (Fig. 1). November Garapota beel in West Bengal did not to March was the period when spawning precisely follow cube law, the closeness took place and after spawning the fish of the value to ‘3’ and the possible needed to feed actively for revitalization influence of internal and external factors, and re-maturing of ova. as described by Le Cren (1951), it may Length weight relationship be considered that the fish followed fairly isometric growth. Establishing the relationship between length and weight is useful in Reproductive biology fishery management by helping The fecundity of the fish ranged prediction of potential yield and from 936 to 13,860. The relative determination of size at capture for fecundity (number of ova per gram body) obtaining MSY as these management ranged from 191 to 1918 with an average parameters are directly related to weight of 894. The fecundity was lower for the of the fish. The relationship is also useful size groups examined from the beel when in differentiating small taxonomic compared to those reported (Chonder, units, as variations might occur within 1977) for similar size groups from rivers. populations of different localities (Le This may be due to the confined nature Cren, 1951; Chonder, 1972). A common of the beel ecosystem. The ovaries were length weight relationship established grouped into seven stages as stage I for G. chapra from the beel showed a (Immature) to stage VII (spent). The straight-line equation. The regression mature ovaries of the fish were paired, equation derived is Log W = 2.8576 Log yellow in colour and occupied the entire L – 4.7564 (R2 = 0.9176). The equation body cavity. The monthly progression of and the correlation coefficient suggested ova diameter showed that immature ova a close relation between the length and (0.05-0.13 mm) were present in all the weight. The species do not follow the months along with other stages of ova. cube law, as the weight of the fish The percentage occurrence of maturing increases slightly less than the cube of ova (0.21-0.71 mm) was higher from its length. The scatter diagram of the March to October. March to June and length and weight is given in Fig. 2.The September to October was the period value of regression coefficient computed when the percentage of occurrence of ripe was 2.8576. For a fish, which maintains ova (0.71-1.28 mm) was at its peak. its shape throughout its life, the value During July to August and November to of regression coefficient will be ‘3’ December, the percentage of ripe ova was (Verghese, 1961; Talwar, 1962). This Biology of Gudusia chapra 77

1.8 1.6 1.4 y = 2.8576x - 4.7564 30 a 1.2 b R2 = 0.9176 1 20 c 0.8 0.6 10 0.4 0 0.2 Frequency (%) 0

0 0.5 1 1.5 2 2.5 0.05 0.21 0.46 0.62 0.79 0.95 1.11 Log length (mm) Ova diameter Fig. 2. Length weight relationship of G. chapra Fig. 5. Frequency of occurrence of eggs of different diameter in ripe ovaries

1. 4 60 1. 2 1

50 0.8

Kn 0.6 0.4 40 0.2 0 30 AMJJASONDJF

Percentage 20 Months Fig. 6. Monthly variations in relative con- 10 dition factor of G. chapra 0 A these values begin to drop, indicating M J J A S O N m) spawning, which corroborated the D J (m Months F M a Ov spawning period inferred from ova diameter progression. The lowest values Fig. 3. Monthly changes in percentage oc- currence of ova of different diameter. of GSI were during November to January.

7 1 It is well known that fishes exhibit 6 GSI Gonad weight 0.8 various types of spawning, which are

) 5 0.6 closely related to the development and 4 distribution of the eggs (Hickling and SI (% 3 0.4 G 2 Ruthenberg, 1936; Prabhu, 1956). 0.2 1 (g) weight Gonad Separate polygons drawn for individual 0 0 fishes in the same stage of maturity AMJ JA SOND J FM showed no difference in ova diameter Months frequency, indicating the absence of any Fig. 4. Monthly variations in the gonad variation in the spawning periodicity weight and GSI of G. chapra between individuals. Hence a common low, indicating the months of shedding polygon was made. The ova diameter of ova. This shows that the species distribution showed that in addition to spawns more than once in a year (Fig. the mode ‘a’ formed by immature ova 3). The monthly variations in the gonad (between 0.05 and 0.21 mm) there are weight and gonado somatic index (GSI) two other modes; mode ‘b’ at 0.79 mm of the fish (Fig. 4) also showed peaks and mod ‘c’ at 0.95 mm (Fig. 5). The during March, April to June (0.79-0.85 g modes ‘a’ and ‘b’ are clearly separated and 4.77-6.04% respectively) indicating and the modes ‘b’ and ‘c’ are closely set. development of ovary and thereafter It is likely that the ova ranging from 0.46 G. K. Vinci et al. 78 to 1.11 mm are the stock of eggs to be Wetland Division for their shed during the next spawning season. encouragement and assistance. The The mode ‘a’ indicates the recruitment authors are also indebted to the staff of stock, which is usually present in the the Floodplain Wetlands Division, ovaries throughout the year (Fig. 3). It Barrackpore, especially to Ms. Suvra is generally known that the spawning Saha for technical assistance. period of a fish will be short and definite References if the mature ova are sharply separated from the stock of immature ova (Hickling Brown, E. Margaret 1957. The Physiology of and Rutenberg, 1936). Two modes (b and Fishes. Vol. 1, Academic Press, New c) in the mature class of ovary indicated York, 447 pp. that there may be more than one Chonder, S. L. 1972. Length-weight spawning by releasing eggs in batches relationship of mature female Labeo as indicated in Fig. 3. gonius (Hamilton) from the Keetham reservoir. J. Inland Fish. Soc. , 4: The values of relative condition 216-217. factor Kn, a measure of the well being of the fish (Le Cren, 1951), ranged from 1 Chonder, S. L. 1973. A possible separation of races of Gudusia chapra (Hamilton) to 1.3 indicating a general well being of by means of length-weight correlation. the fish. The Kn value depends on the Proc. Indian Acad. Sci., 78 B: 73-79. physiological factors like maturity and spawning as well as food availability Chonder, S. L. 1975. Studies on (Brown, 1957). The Kn values did not morphometry, biology, osteology and haematology with their special reference show marked variations except minor to analyse the races of Gudusia chapra peaks in July, October and March, Hamilton. PhD. Thesis, Agra University. corresponding to the periods of gonad maturity and spawning. These peaks are Chonder, S. L. 1977. Fecundity and its role not prominent, probably due to the close in racial studies of Gudusia chapra (Pisces:Clupeidae) Proc. Indian Acad. breeding period and releasing of eggs in Sci., 86 B (4): 245-254. batches. Devashish, K. 2000. Length-weight G. chapra is a surface feeder. Algae, relationship and condition factor in especially Myxophyceae were the Gudusia chapra (Ham.-Buch.) and Botia preferred food item. The spawning period dario (Ham.-Buch.) from Chatla Haor was from March to October in which the (Floodplain wetland) in Cachar District fish release eggs in batches. Fecundity of Assam. Environment and Ecology, ranged from 936 to 13,860 and the 18(1): 227-229. fecundity factor was 894 eggs. The Grimes, B. and Huntsman 1980. species from Garapota beel in West Reproductive biology of the Vermilion Bengal does not precisely follow cube snapper, Rhomboplites aurorubens from law, yet the closeness of the value to ‘3’ North Carolina and South Carolina. indicated fairly isometric growth. Fish. Bull., 78: 137-146. Hickling, C. F. and E. Rutenberg, 1936. The Acknowledgements ovary as an indicator of spawning period The authors are grateful to the in fishes. J. Mar. Boil. Ass. UK, 21: 311- Director, Central Inland Fisheries 317. Research Institute, Barrackpore and Dr. Hile, R. 1936.Age and growth of the cisci V. V. Sugunan, Head, Floodplain Leucichthys artedi (Le Sucer) in the Biology of Gudusia chapra 79

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Date of Receipt : 07-06-2004 Date of Acceptance : 25-10-2004