Journal of Threatened Taxa | www.threatenedtaxa.org | 26 November 2023 | 15(11): 24255–24260

 

ISSN 0974-7907 (Online) | ISSN 0974-7893 (Print) 

https://doi.org/10.11609/jott.8553.15.11.24255-24260

#8553 | Received 24 May 2023 | Final received 10 September 2023 | Finally accepted 23 October 2023

 

 

Body growth and condition of endangered Tor putitora (Hamilton, 1822) (Actinopterygii: Cypriniformes: Cyprinidae) in the crucially important breeding and nursery grounds of the Ganga stock

 

Priyanka Rana 1  & Prakash Nautiyal 2

 

1,2 Aquatic biodiversity Unit, Department of Zoology, H.N.B. Garhwal University, Srinagar, Uttarakhand 246174, India.

1 priyankarana.hnb@gmail.com (corresponding author), 2 pn.mahseer@gmail.com

 

 

Editor: Mandar Paingankar, Government Science College Gadchiroli, Maharashtra, India.        Date of publication: 26 November 2023 (online & print)

 

Citation: Rana, P. & P. Nautiyal (2023). Body growth and condition of endangered Tor putitora (Hamilton, 1822) (Actinopterygii: Cypriniformes: Cyprinidae) in the crucially important breeding and nursery grounds of the Ganga stock. Journal of Threatened Taxa 15(11): 24255–24260. https://doi.org/10.11609/jott.8553.15.11.24255-24260

  

Copyright: © Rana & Nautiyal 2023. Creative Commons Attribution 4.0 International License.  JoTT allows unrestricted use, reproduction, and distribution of this article in any medium by providing adequate credit to the author(s) and the source of publication.

 

Funding: The present study was funded by the University Grant Commission (UGC) under the Junior Research Fellowship (JRF) scheme provided to the first author.

 

Competing interests: The authors declare no competing interests.

 

Author details: Priyanka Rana is currently engaged in the pursuit of her Ph.D. within the Aquatic Biodiversity Unit of the Zoology Department at Hemvati Nandan Bahuguna Garhwal University, located in Srinagar, Uttarakhand. She is working on the reproductive biology of Himalayan Mahseer under the current climatic and land use land cover changes in the Nayar basin of the Ganga River. Professor Prakash Nautiyal is currently affiliated with Aquatic Biodiversity Unit, Zoology Department, Hemvati Nandan Bahuguna Garhwal University, Srinagar Uttarakhand. His area of specialization includes fisheries ecology, conservation ecology of golden mahseer, mountain river ecology, and aquatic biodiversity.

 

Author contributions: PR conducted the data collection, performed the statistical analysis, and drafted the initial manuscript. PN played a critical role in reviewing and providing constructive feedback on the initial draft and finalized the content for publication.

 

Acknowledgements: The authors acknowledge University Grant Commission, Delhi, India for supporting the study under the NET-JRF scheme provided to the first author. Authors also acknowledge the head (PN), Department of Zoology, H.N.B. Garhwal University, Srinagar, Uttarakhand, India for facilitating successful accomplishment of work.

 

 

Abstract: The study evaluates seasonal differences in length-weight relationship and relative condition factor (Kn) of Tor putitora in the Nayar, a critical breeding and nursery ground in the mountain zone of the Ganga. The growth coefficient of T. putitora varies seasonally between 2.86 and 2.99 while relative condition factor between 1.00 ± 0.06 to 1.061 ± 0.3. Mahseer shows negative allometric growth (except the monsoon season) with better condition factor throughout the study period. The present Kn factor for different size groups show deviation from past which may be due to inadequate food resources or excessive fishing in the Nayar.

 

Keywords: Allometric growth, exploitation, growth coefficient, isometric, juveniles, Kn, Mahseer, length-weight, Nayar, spawning.

 

 

Introduction

 

Himalayan Mahseer is an Endangered (Jha et al. 2018) endemic megafauna of Himalayan rivers that completes its migratory cycle within glacier-fed and spring-fed tributaries for spawning/feeding and rearing purposes (Nautiyal 1996; Bhatt et al. 2000; Nautiyal et al. 2001). Presently, the mahseer fishery of Indian subcontinent is declining under continuous threat of indiscriminate fishing, habitat degradation/fragmentation, climate change (Nautiyal 2014) and introduction of non-native fish (Gupta et al. 2019). The coupled effect of all these factors could be reflected in their growth, body condition, mortality, and recruitment of the next cohorts.  Length-weight relationship is an easy tool for the assessment of the body growth and condition of the fish at the individual as well as population level. The relationship also offers a measure of the health of the fish population (Safran 1992), as well as a comparison of the life history characteristics of populations living in various geo-climatic regions. Various changes in the expected size, length-weight and hence growth of the fish due to major or minor changes in their life cycle could be perceived through the length-weight relationship (Le Cren 1951). Further, the relative condition factor (Kn) makes an assessment if increase in the body weight is in accordance with the desirable reproductive potential and recruitment rate. The study, therefore, evaluates the present status of the Himalayan Mahseer stock in the breeding and nursery grounds in the Nayar.

 

Study area 

The Nayar is a spring-fed perennial river that originates from the Dudhatoli Hills in the Pauri Garhwal District of Uttarakhand. The confluence of the Nayar with the Ganga is located  ̴10 km downstream from Devprayag, Uttarakhand. The stock in the Ganga foothills ascends the Nayar annually (Nautiyal et al. 2001).

 

 

Materials and Methods 

 

The present study was based on the samples (N = 1966) of Putitor Mahseer collected from the local fishermen (Image 1) during July 2021 to October 2022 at weekly intervals. Further, the 1980s data were obtained monthly by the second author (PN), which contributed to a small sample size compared to weekly collection. The samples were cleaned with a cotton cloth. Thereafter, the total length and weight of the individual fish were recorded using measuring tape and a digital balance respectively. 

Length-weight relationship was estimated using logarithmic form of the following equation

Log W = Log a + b Log L

Where, W is the weight of the sample in gm, L is the total length of the fish sample in cm while a and b are the intercept and slope respectively. The regression coefficients and the length-weight relationship were analyzed using Microsoft Excel 2016 software.

Significance of b value, i.e., Ho: ß = 3 was evaluated using t-test as 

        |b − 3|

t =  –––––––

             Sb

where, Sb is the standard error of b.

Relative condition factor was estimated using 

          Wo

Kn = ––––

          Wc

Where, Wo is the observed weight and Wc is the calculated weight obtained from length-weight analysis.

 

 

Results

 

The examined fish samples ranged from 6.2 to 121.9 cm in the length and 2.1 to 25,000 g in weight, among which individuals below 25 cm constituted the resident stock of the Nayar (Table 1) as they were recorded throughout the study period. However, individuals measuring above 25 cm were the migratory brooder stock of mahseer as they were recorded only during the monsoon season (Table 1). Among the resident stock, the fish measuring between 10–15 cm was high in total sample followed by 15–20 cm and 20–25 cm. 

The seasonal growth coefficient (b) varied between 2.86–2.99 (Table 2) which is within the expected suitable range of growth (Froese 1998). Except for the monsoon season (2021), mahseer has shown negative allometric growth as t-test analysis rejected the hypothesis i.e., Ho: ß = 3, at 0.05 level (Table 2). However, seasonal analysis of length-weight data of 1980–1981 has shown isometric growth type in winter season while negative allometric growth type for monsoon and summer season (Table 3). The b value was estimated as 2.95, for the pooled data of the present stock of mahseer, showing isometric growth type which was also recorded in earlier studies from the Nayar and other geo-climatic locations (Table 4). 

The mean value of monthly relative condition factor for the present Mahseer cohort ranged between 1.00 ± 0.06 to 1.061 ± 0.3 (Table 5 and Figure 1). The peak of Kn was observed during monsoon season (July to August) which usually refers their breeding period as indicated by presence of ripe individuals and fry-fingerlings (Table 1). Further, a moderate relative condition factor ranging between 1.003 ± 0.03 to 1.005 ± 0.09 has been observed in between the monsoon periods. However, the current cohort’s juveniles have a relatively high relative condition factor, in contrast to the 1980’s cohort, where adults had a greater Kn factor (Figure 2).

 

 

Discussion

 

The largest size of the Himalayan Mahseer encountered during this study was 121.9 cm in August. This was comparatively smaller than the past size (133.7 cm) in 1980–1981 (Nautiyal & Lal 1981). The Mahseer ranging above 40 cm was very low in number as they are part of migratory stock ascending from Ganga into Nayar for breeding purposes. However, other parts of India have also reported a drop in the size of other Mahseer fisheries and a low share in overall fish catches (Minimol 2000).  

The resident 1980’s cohort of the Nayar (4.1–49 cm) including fingerlings, juveniles and adults have shown negative allometric growth indicating no significant weight gain. However, winter season has shown comparable weight gain with respect to length increment which may be due to availability of food resources as winter is the most productive period of the Nayar (Nautiyal 1986). However, negative allometric growth in 2021–22 cohort throughout the seasons, somehow, indicate depletion of resources. Additionally, the isometric growth in monsoon and pooled data may be attributed to inclusion of large sized brooders with ripe eggs in resident stock (Table 1). Therefore, 1980’s cohort has shown negative allometry in monsoon season due to prevalence of fingerlings and juveniles (<25 cm) which do not possess mature gonads. The previous studies on T. putitora in different regions have also shown isometric, positive and negative allometric growth patterns with varying geographic and climatic conditions (Table 3). Therefore, the seasonal fluctuations in sample size, maximum length, gonad maturity, food availability, feeding intensity (Le Cren 1951) may have played a major role in the body growth and condition of present cohort of Himalayan Mahseer. 

During breeding season large percentage of the total body weight is influenced by increase in gonad size of prospective brooders as gonads undergo rapid development during spawning. Hence Kn attained a peak in monsoon and fell abruptly thereafter. However, a sudden drop in June may be attributed to the decline in the feeding intensity from summer onwards (Nautiyal 1996) which coincides with the decline in the food resources from winter afterward. Similar trend in relative condition factor was observed earlier also and was used to infer the monsoon as breeding season (Nautiyal 1985). However, in contrast to 1980’s cohort (Nautiyal 1985), the small size groups have shown better fitness while health condition of adults have deteriorated from past (Figure 1) which may be caused by overfishing of potential brooders leading to overexploitation, hampered recruitment, fragmentation of habitat and subsequent degradation, scarcity of food resources and decline in feeding intensity after attaining a length of 22 cm (Nautiyal 1989). However, low Kn for juveniles (<20 cm) and comparatively better in adults (> 20 cm) was recorded form the Khoh, Kolhu, and Mandal (tributaries of Ramganga) in the Uttarakhand (Atkore et al. 2007).

 

 

Conclusion

 

The Himalayan Mahseer deviated from the past in terms of body growth, condition and fitness. The mahseer of present cohort are not robust compared to past which may be attributed to either lack of food resources, decline in feeding intensity or increasing fishing pressure. Although the Mahseer has shown better condition throughout the present study period but the overall wellness in the adults has declined while inclined in the juveniles which may be related to habitat suitability or overfishing of larger size groups. Therefore, this study provides insight about the declined growth in body size and condition of different size groups of endangered Himalayan Mahseer. 

 

Table 1. Monthly variations in frequency (as %) of different size groups (in cm) of Tor putitora in the Nayar.

 

2021

2022

 

Monsoon

Winter

Summer

Monsoon

Size-group

J

A

S

O

N

D

F

M

A

M

J

J

A

S

O

1–5

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

- 

 -

 -

 -

5–10

27.0

19.6

 -

19.5

6.2

31.3

35.5

 -

 -

 -

0.7

 -

35.2

 -

28.7

10–15

22.2

19.6

6.7

50.2

52.7

67.2

64.5

18.2

39.8

8.2

35.2

34.5

9.9

5.6

63.2

15–20

19.0

13.7

28.9

25.5

17.8

 -

 -

41.6

48.9

35.4

35.9

13.8

20.9

21.1

8.0

20–25

9.5

14.7

38.0

2.4

18.6

1.6

 -

22.1

9.1

45.6

22.1

17.2

8.8

32.2

 -

25–30

7.9

8.8

15.1

0.4

3.1

 -

 -

5.2

 -

8.8

6.2

13.8

6.6

22.2

 -

30–35

1.6

3.9

4.9

 -

1.6

 -

 -

7.8

 -

1.4

 -

6.9

1.1

5.6

 -

35-40

3.2

4.9

1.8

0.8

 -

 -

 -

 -

0.4

0.7

- 

3.4

3.3

3.3

 -

40–45

 -

2.0

0.4

1.2

 -

 -

 -

2.6

1.3

 -

 -

 -

5.5

3.3

 -

45–50

1.6

4.9

0.4

 -

 -

 -

 -

1.3

0.4

 -

 -

6.9

3.3

2.2

 -

50–55

1.6

2.9

0.4

 -

 -

 -

 -

1.3

 -

 -

 -

 -

2.2

1.1

 -

55–60

1.6

1.0

0.4

 -

 -

 -

 -

 -

 -

 -

 -

 -

1.1

2.2

 -

60–65

1.6

1.0

0.4

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

65–70

 -

1.0

0.7

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

70–75

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

1.1

 -

75–80

1.6

1.0

0.4

 -

 -

 -

 -

 -

 -

 -

 -

3.4

2.2

 -

 -

80–85

 -

 -

-

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

85–90

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

90-95

1.6

 -

0.4

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

95–100

 -

 -

-

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

100–105

 -

 -

0.4

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

105–110

 -

 -

0.4

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

110–115

 -

 -

0.4

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

115–120

 -

 -

0.4

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

120–125

 -

1.0

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 -

 

 

Table 2. Seasonal descriptive statistics of length-weight relationship of T. putitora in the Nayar (2021–2022).

Season

N

Total length (cm)

Total Weight (gm)

a

b

r2

T0.05

Growth *

Min.

Max.

Min.

Max.

Monsoon

700

7.5

121.9

4

25000

-2.07

2.99

0.99

0.84

I

Winter

224

8.9

34.1

6.65

362.64

-1.97

2.91

0.99

4.64

NA

Summer

745

15

51.2

34.01

1167.16

-1.89

2.86

0.98

4.63

NA

Monsoon

297

6.2

78.9

2.1

5000

-1.98

2.91

0.98

4.21

NA

Pooled

1966

6.2

121.9

2.1

25000

-2.01

2.95

0.97

1.77

I

* t—t-test | I—Isometric | NA—Negatively allometric.

 

 

Table 3. Seasonal descriptive statistics of length-weight relationship of T. putitora in the Nayar (1980–1981).

Season

N

Total length (cm)

Total weight (gm)

a

b

r2

T0.05

Growth

*

Min.

Max

Min.

Max

Monsoon

59

4.1

25

0.548

113.5

-2.00

2.88

0.98

2.30

NA

Winter

134

4.9

21.6

1.025

83

-1.98

2.91

1.00

0.49

I

Summer

52

7.1

49

2.98

875.5

-0.12

1.33

0.68

2.35

NA

* t—t-test | I—Isometric | NA—Negatively allometric.

 

 

Table 4. Growth coefficient of T. putitora form the Nayar and other regions of India.

River/Other

State

b

Growth *

Reference

Nayar

Uttarakhand

2.88

I

Lal & Nautiyal 1980

Nayar

Uttarakhand

2.98

I

Nautiyal 1985

Pong Reservoir

Himachal Pradesh

3.15

PA

Johal et al. 2005

Ladhiya

Uttarakhand

2.99

I

Patiyal et al. 2010

Jia Bharoli

Arunachal Pradesh

3.108

I

Ali et al. 2014

Beas

Himachal Pradesh

3.082

I

Ali et al. 2014

* I—Isometric | PA—Positive Allometric | NA— Negatively Allometric.

 

 

Table 5. Monthly relative condition factor (Kn) of T. putitora in the Nayar.

Month

N

Kn ± S. D.

July

63

1.013 ± 0.16

August

102

1.015 ± 0.18

September

284

1.009 ± 0.13

October

251

1.004 ± 0.08

November

129

1.003 ± 0.08

December

64

1.003 ± 0.08

February

31

1.003 ± 0.08

March 

77

1.004 ± 0.09

April

231

1.003 ± 0.08

May

147

1.003 ± 0.08

June

290

0.954 ± 0.09

July

29

1.061 ± 0.30

August

91

1.027 ± 0.31

September

90

1.005 ± 0.11

October

87

1.002 ± 0.06

Pooled

1966

1.013 ± 0.16

 

 

For figures & image - - click here for full PDF

 

 

References 

 

Ali, S., A. Barat, P. Kumar, J. Sati, R. Kumar & R.S. Haldar (2014). Study of length-weight relationship and condition factor for the Golden Mahseer, Tor putitora from Himalayan rivers from India. Journal of Environmental Biology 35(1): 225–228.

Atkore, V.M., K. Sivakumar & A.J.T. Johnsingh (2007). Length-weight relationship and relative condition factor of juvenile Golden Mahseer Tor putitora (Hamilton, 1822), in the tributaries of Ramganga river, Uttarakhand. Journal of the Bombay Natural History Society 104: 161–164.

Bhatt, J.P., P. Nautiyal & H.R. Singh (2000). Population structure of Himalayan Mahseer, a large cyprinid fish in the regulated foothill section of the river Ganga. Fisheries Research 44(3): 267–271. https://doi.org/10.1016/S0165-7836(99)00083-1

Froese, R. (1998). Length-weight relationships for 18 less-studied fish species. Journal of Applied Ichthyology 14(1–2): 117–118. https://doi.org/10.1111/j.1439-0426.1998.tb00626.x

Gupta, N., M. Everard, P. Nautiyal, I. Kochhar, K. Sivakumar, J.A. Johnson & A. Borgohain (2019). Potential impacts of non-native fish on the threatened mahseer (Tor) species of the Indian Himalayan biodiversity hotspot. Aquatic Conservation: Marine and Freshwater Ecosystems 30(2): 394–401. https://doi.org/10.1002/aqc.3275

Jha, B.R., A. Rayamajhi, N. Dahanukar, A. Harrison & A.C. Pinder (2018). Tor putitora. The IUCN Red List of Threatened Species 2018: e.T126319882A126322226. Accessed on 20 October 2021. https://doi.org/10.2305/IUCN.UK.2018-2.RLTS.T126319882A126322226.en

Johal, M.S., R.K. Negi & S. Onkar (2005). Length weight relationship of Golden Mahseer Tor putitora (Hamilton) from Pong Dam Reservoir, Himachal Pradesh. Uttar Pradesh Journal of Zoology  25(1): 85–88.

Lal, M.S. & P. Nautiyal (1980). Ecological studies on some hillstream fishes of Garhwal Himalaya 2. Length-weight relationship of Tor putitora (Hamilton). Indian Journal of Zootomy 21: 107–123.

Le Cren, E.D. (1951). The length-weight relationship and seasonal cycle in gonad weight and condition in the perch (Perca fluviatilis). The Journal of Animal Ecology 20(2): 201–219. https://doi.org/10.2307/1540

Minimol, K.C. (2000). Fishery management in Periyar Lake. PhD Thesis. Mahatma Gandhi University, Kottayam, India, 196 pp.

Nautiyal P. (1985). Observations on the length-weight relationship and relative condition factor of Garhwal Himalayan Mahseer with reference to its fishery. Indian Journal of Animal Sciences 55: 65–70.

Nautiyal, P. (1986). Studies on the riverine ecology of torrential waters in the Indian uplands of the Garhwal region III. Floristic and faunistic survey. Tropical Ecology 27: 157–165.

Nautiyal, P. (1989). Mahseer conservation: problems and prospects. Journal of the Bombay Natural History Society 86(1).

Nautiyal, P. (1996). The river valley projects in Garhwal region: Impact on the population dynamics of endangered Himalayan Mahseer with emphasis on bio conservation. Final Technical Report submitted to GDP, MOEN, New Delhi (J-11013/8/92-GDP;24-09-1992).

Nautiyal, P. (2014). Review of the art and science of Indian mahseer (game fish) from nineteenth to twentieth century: road to extinction or conservation? Proceedings of the National Academy of  Sciences, India Section B: Biological Sciences 84: 214–236. https://doi.org/10.1007/s40011-013-0233-3

Nautiyal, P. & M.S. Lal (1981). Recent records of Garhwal Mahseer (Tor putitora) with a note on its present status. Journal of the Bombay Natural History Society 79(3): 593–595.

Nautiyal, P., S.N. Bahuguna & R.P. Thapliyal (2001). The role of ecological factors in governing the direction, time and purpose of migration in Himalayan Mahseer Tor putitora (Ham.). Applied Fisheries and Aquaculture 1(1): 133–138.

Patiyal, R.S., R.C. Sharma, P. Punia, M. Goswami & W.S. Lakra (2010). Length–weight relationship of Tor putitora (Hamilton, 1822) from the Ladhiya River, Uttarakhand, India. Journal of Applied Ichthyology 26(3): 472–473. https://doi.org/10.1111/j.1439-0426.2010.01466.x

Safran, P. (1992). Theoretical analysis of weight length relationship in the juveniles. Marine Biology 112: 545–551. https://doi.org/10.1007/BF00346171