Studies on the Age and Growth of the Orange fin labeo, Labeo calbasu (Hamilton) from Lower Anicut, Tamil Nadu

INTRODUCTION

2.0. Materials and Methods

In this study the freshwater fish orange fin labeo  L.  calbasu  (Hamilton, 1822) (vernacular  name is   Karuppu chal) were  collected  from a  branch  of  Kollidam  river  namely  Vadavar  river, Tamil Nadu. A total of 110 specimens of L. calbasu (total length ranging from 10.2 to 44.2 cm) were used for the length- frequency analysis and scale methods. The experimental fishes were divided into 50 mm length groups for length-frequency analysis. For age determination, scales were taken from the same point from each fish (i.e. from the left side of the body above the lateral line, in shoulder region). 5-10 scales were taken from each fish and stored in small coded envelope. Later these scales were washed in tap water and dried on a filter paper. Three scales from each fish were mounted dry between two glass slides, fastened each end by means of cello tape. The examination and measurements of scales were made using a binocular microscope and light microscope, fitted with ocular micrometer. The total length of scale was recorded from anterior to posterior margin, along a vertical imaginary line passing through the center.

3.0. Results

3.1. Age Determination by Length-Frequency Method

The length of L. calbasu during the present study varied from 124 mm to 541 mm. The female fishes were found in great abundance (Table-1). Four length groups are discernible in the length frequency polygons (Fig. 1) at modal lengths 250, 283, 385 and 442mm. The entire data were pooled; Males, females and juveniles and their combined length frequencies as percentage are shown in (Fig. 2). It is therefore, probable that modal length 250 mm represents as 0+ age group and the subsequent modal length 283mm 385mm and 442 mm as 1⁺, 2⁺   and 3⁺ age group respectively. Beyond three years, the peaks are less distinct. The age estimate from the length frequency analysis of L. calbasu in the present study yielded four age groups i.e. from 0+ to 3+.

3.2. Reading of scales

The radii on all scales were more or less evenly spaced except a few peripheral ones. Ages were determinate by counting the number of radii.  Both complete and incomplete radii were counted.  The analysis of scales, as seen from the (Table-2), showed average number of radii on the scales of same fish. The average number of radii, however, increased proportionately with the size of fish. In the length group of (101-150) possess 0 (zero) radii, in the length group (151- 200) and (201- 250) possess 1radii, in the size group of (251-300) and (301-350) possess 2 radii, in case of size group (351-400) and (401-450) possess 3 radii, and (401-450) possess 4 radii (Fig. 3). In the scales of largest size group, some sorts of erosion and absorption of tissue was also noticed. The age determination of L. calbasu in the present study from scales method resulted into six age groups i.e. from 0+ to 5+.

3.3. Body- scale length relationship

Table-2. Showed the size of scales in mm, the range and average number of radii recorded on scales, and the body length versus scale length ratio for specimens arranged in 50 mm interval size group. It will be seen from this data that, L/S ratio increased as total length of fish increased, or in other words the relative size of scales decreases with the increase in total length of fish. The empirical data of total length and scale length when plotted, gave a weak curve. This relationship was converted into a straight line by log-log relationship. The computed regressions gave the following equation.

Log L =           +             Log S

Where L = total length of fish in mm, and

S = is total length of scale in mm.

Thus, the relationship between body length and scale length was observed to be linear.

4.0. Discussion

In the present study the age determination of the carp, Labeo calbasu (Hamilton) from, Vadavar river Lower Anicut has been assessed from the 110 specimens. Using length-frequency method and scale study, it was found that L. calbasu attains model length of 250, 283, 385 and 442 mm at the end of zero, 1st, 2nd and 3rd years of life respectively. Rao and Rao (1972) used length frequency method for the age determination in L. calbasu from River Godavari, India. They concluded that the fish attains modal length of 210, 270, 330 and 410 mm as zero, 1, 2 and 3 years of life. Narejo et al., (1999) reported age in Tenualosa ilisha from River Indus at modal length of 225, 275, 325 and 375 mm at the end of zero+, 1+, 2+, and 3+ year of life and Narejo et al., (2009) used length frequency method or the age determination L. calbasu  from Keenjhar lake, Sindh. They concluded that the fish attains model length of  model length of 275, 332, 370 and 415 mm at the end of zero, 1st, 2nd and 3rd years of life. The results of the present study agreed or very close to the findings of Rao and Rao (1972) in Labeo calbasu, little variations might be due to the different environmental conditions where two populations were live.

During the present investigations the scale method was also used for the age determination of L. calbasu. The age determination from scale method in the present study resulted in five groups from 0 to 5 at the modal lengths of 150, 283, 335, 395 and 445 mm. Similar observations have been reported by Gupta and Jhingran (1973) used scale method for aging Labeo calbasu. They reported seven age groups at the modal lengths of 188, 291, 381, 468, 543, 618 and 681 mm from Allahabad, India  and Narejo et al., (1999) reported seven age groups from scale method in Tenualosa ilisha from River Indus at modal lengths of 188, 227, 288, 335, 375, 440 and 460 mm. In the present study the body-scale relationship of L. calbasu from Keenjhar Lake was calculated and found liner relationship between the two variables. Various workers in different fish species were reported similar linear relationship between the body length and scale length by Rao and Rao (1972), Gupta and Jhingran (1973), Vinci and Sugunan (1981) in L. calbasu from India. Narejo et al., (1999) in T. ilisha from River Indus and Narejo et al., (2000) in Gudusia chapra from Keenjhar Lake and Narejo et al., (2009)  L. calbasu from Keenjhar Lake, Sindh.

The efficacy of age determination by the length frequencies depend upon a restricted single spawning season, and growth being such that length of fish of an age group confirm to normal distribution. In the present study, the length frequency distribution showed model increments with fish size and assuming that Labeo calbasu in the Lower Anicut has single spawning season, the above age estimates may be regarded as satisfactory. However, there was no direct evidence to prove the accuracy of these estimates. It is difficult to draw any valid conclusions regarding the age of Labeo calbasu from the length frequency distribution method unless validated by some other techniques of an age determination. The reason is that extensive overlap of the frequency distribution of the successive age groups, selectivity of gear, poor representation of one or two year classes, deferential rate of growth in males, females and juveniles.

References

Azadi M A and M A Kuddus 1995 Studies on the age and growth of a carp, Labeo calbasu (Hamilton) (Cyprinidae: Cypriniformes) from Kaptai reservoir, Bangladesh. Chittagong Univ. Stud. Part II: Science, 19(1): 7-17

Beganal T B (ed) 1974 The aging of fish Proceeding of an International Symposium on the Ageing of fish Reading UK 19 July 1973Old working Survey (UK): Unwin Brothers Limited, Chessington KT9 2NY, U.K. pp 114-123

Beamish R J and MacFarlane G A 1996 Current trends in age determination methodology In: Summerfelt R.C and Hall G.E. (eds.) The age and growth of fish The Iwowa State University Press. Ames Iowa. Pp 15-42

Diget J and Le Guen J C 1975 Les criters dage chez les posissons. In: Lamotte M and Bourliniere F (eds.) Paris. Pp253-280

Gupta S D and A Jhingran 1973 Aging Labeo calbasu (H) through its scales J. Inland. Fish. Soc. India,  (5); 126-128

Narejo N.T A M Mastoi P K Lashari M Abid M Y Laghari and H Mahesar 2009 Age determination of carp, Labeo calbasu(Hamilton) from Keenjhar lake, Sindh Univ. Res. Jour. (sci. Ser.) Vol.14 (1) 83-86

Meunier F J  1988 Determination de lage individual chez osteichtyens a laide de la squlettochronologique. Acta (Ecological/Ecol. Gener. 9(3): 299-329

Meunier F J  Pascal M Loubens G 1979 Comparison de methods  squlettochronologique et considerations fonctionelles sur le tissue osseu acelluaire d un osteichtyen du lagon new-caledonien, Lethrius nebulosus (Forskal 1755) Aquaculture (17): 137-157

Mills K H and Beamish R J 1980 Comparision of fin ray and scale age determination for lake whitefish (Coregonus clupeaformes) and their implications for estimates of growth and annual survival Can. J. Fish. Aqua. Sci. (37): 534-544

Panfili J de Pontual H Troadec J P Wright P J (eds.) 2002 Manual of fish sclerochrology. Brest, France, IFREMER-IRD co-edition. 464pp

Rao M G and L H Rao 1972 On the biology of Labeo calbasu (H) from the River Godavari. J. Inland. Fish. Soc. India, (5): 74-86

Summerfelt R C and Hall G E 1987 Age and growth of fish. The Iwoa State Universsity Press, Ames, Iowa. 544pp

Vinci G K and V V Sugunam 1981 Biology of Labeo calbasu (H) from Nagarjunasagar reservoir, AP India, J. Inland. Fish. Soc.India, (2): 22-39

Table 1: Length frequency distribution of Labeo calbasu from Lower Anicut according to sex and their combined percentage frequencies

Table 2: Relationship between body length, scale length and number of radii on scales of Labeo calbasu from Lower Anicut

Fig. 1: Length frequency distribution of Labeo calbasu from lower Anicut                   Fig 2: Percentage frequency of Labeo calbasu from Lower Anicut

CONFLICTS OF INTEREST