Growth Patterns of Endemic Fish Species from the Lancang River, Southwest China

Huiping Ding1, Tian Zhong1, Yang Yang2 and Zhiming Zhang2*

1School of Animal Science and Nutritional Engineering, Wuhan Polytechnic University, Wuhan 430070, China.

2Ecological Technology Engineering Center, Institute of Hydroecology, MWR and CAS, Wuhan 430079, China.

ABSTRACT

This study provided estimates of length-weight relationships (LWRs) and length-length relationships (LLRs) of seven endemic fish species collected from the Lancang River, Southwest China and its tributaries. Totally, 435 specimens belonging to 3 families and 5 genera were collected from 2018 to 2022, using various types of fishing techniques. Total length (TL), standard length (SL) and body weight (BW) of each specimen were measured to the nearest 0.1 cm and 0.1 g, respectively. This study presents the first public records of LWRs parameters of Garra mirofrontis, Sikukia longibarbata, Sikukia flavicaudata, Schistura kengtungensis, Glyptothorax macromaculatus and Glyptothorax zanaensis, except for Onychostoma gerlachi. The allometric coefficient b valves for all LWRs ranged from 2.7540 to 3.1038, and the r2 values for all LWRs estimates ranged from 0.9705 to 0.9858. Comparison of b value with the expected value 3 showed that growth pattern of S. longibarbata and G. zanaensis were negative allometric, while others performed isometric growth pattern. The mean condition factor (K) of these seven species ranged from 1.31 to 2.77. The mean relative weight ranged between 100.43 to 101.94. This study updated information for FishBase and provided new record of maximum standard length for three species, namely, G. mirofrontis (16.50 cm), S. longibarbata (20.00 cm), and S. flavicaudata (26.50 cm). The findings of this study are essential for the management and conservation of locally indigenous fish and fisheries.

Article Information

Received 22 August 2023

Revised 28 February 2024

Accepted 10 March 2024

Available online 12 September 2024

(early access)

Published 20 August 2025

Authors’ Contribution

All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by HPD, TZ, ZMZ and YY. The first draft of the manuscript was written by HPD and all authors commented on previous versions of the manuscript. All authors read and approved the final version of the manuscript.

Key words

Length-weight relationship, Length-length relationship, Condition factor, Relative weight, Lancang River

DOI: https://dx.doi.org/10.17582/journal.pjz/20230822073904

* Corresponding author: [email protected]

0030-9923/2025/0005-2323 $ 9.00/00

Copyright 2025 by the authors. Licensee Zoological Society of Pakistan.

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).


Introduction

The Lancang-Mekong River is an important international river, located in Southeast Asia. As a typical longitudinal river, the river watershed covers various landscape types and has a fish fauna of exceptional diversity surpassed only by the Amazon watershed (Rainboth et al., 2012). Nearly 200 fish species have been recorded in the river of China section, most of which are endemic species (Hong et al., 2021). However, with the rapid population growth and economic development of countries in the river basin, especially the cascade development in the upper and middle reaches, fish diversity and fishery resources of the Lancang River are experiencing serious threats, which manifested as fish diversity and fish resource decline, homogenization of fish assemblages, miniaturization of fish individual (Li et al., 2013; Ngor et al., 2018; Zhang et al., 2018). Even so, basic biological information on most endemic fish species in the Lancang River is still limited (Li et al., 2019).

Length-weight relationships (LWRs) are basic fish biological data, integrating important information of fish life history including lipid storage, body morphology, and growth rate (Zhang et al., 2017). They are important in fish biology, ecology, fishery management, and conservation (Froese, 2006). According to LWRs, researchers can easily determinate fish weight from length or vice versa, evaluate fishery production, compute condition factor and relative weight (Patrick et al., 2021). Besides, LWRs facilitate biometric and morphological comparisons between fish species in the same taxonomic group or between fish populations from different regions or periods (Froese, 2006; Çiçek et al., 2022). The “b” value calculated from length-weight relationship is usually used to describe the growth patterns of fish according to the comparison the “b” value and the ideal value “3” (Pauly, 1984).

Condition factor and relative weight are other indices calculated from length and weight measurements. Condition factor is used to assess the fullness, nutrition, and the effect of environmental variability on fish (Le Cren, 1951; Lizama et al., 2002; Stevenson and Woods, 2006). Relative weight (Wr) integrates important physiological components of fish life history and offers a strong, accessible metric for managers to assess the overall health and fitness of fish populations, as well as population-level responses to ecosystem disturbances (Rypel et al., 2006; Rypel and Layman, 2008).

Endemic fishes in the Lancang River are important components of the local biodiversity and aquatic food webs. Some endemic fish are important component of local fishery, such as Garra mirofrontis, Sikukia longibarbata, Sikukia flavicaudata, Schistura kengtungensis (Chu and Chen, 1989, 1990). However, there are few data about their biological traits, little information is available on their length and weight, especially LWRs, condition factor and relative weight. To expand the biological knowledge of these fish species and provide basic data for further research, this study provides LWRs, LLRs, condition factors, and relative weights of seven endemic fish species belonging to three families from the Lancang River, for which there is no information regarding the LWRs, even in FishBase (Froese and Pauly, 2023).

Materials and Methods

Study area and sample collection

Samples were collected from the Lancang River and its tributaries, namely, Jidu River, Hei River, Weiyuan River, Buyuan River and Nanla River in southwest China from November 2018, June 2020, April to May and August to September 2022 (Table I, Fig. 1). Gillnets (20-40 m long, 1-3 m high, and mesh size, 1-5 cm), trap nets (20 m × 50 cm × 50 cm, mesh size 1 cm), and electrofishing (20 A, 1 V, 3000 W) were used to collect fish samples. After caught, the specimens were identified to the species level according to the Fishes of Yunnan, China (Chu and Chen, 1989, 1990), and checklist of fishes of Yunnan (Chen, 2013). All scientific names were checked against FishBase (Froese and Pauly, 2023). For each individual, total length (TL), standard length (SL) and total weight (BW) was measured to the nearest 0.1 cm and 0.1 g, respectively. All handling procedures were performed according to the Administration Regulations of Laboratory Animals of China.

 

Table I. Sampling sites and dates of the seven fish species from the Lancang River, China.

Family/ Species

n

Sampling river

Sampling time

U

M

D

Family: Cyprinidae

Garra mirofrontis

87

○

○

Aug.-Sep. 2022

Sikukia longibarbata

63

○

Aug. 2022

Sikukia flavicaudata

48

○

○

Aug.-Sep. 2022

Onychostoma gerlachi

62

○

○

Nov. 2018; Apr.-May, Aug. 2022

Family: Nemacheilidae

Schistura kengtungensis

55

○

○

Sep. 2022

Family: Sisoridae

Glyptothorax macromaculatus

55

○

○

Apr.-May, Sep. 2022

Glyptothorax zanaensis

65

○

○

Jun. 2020; May, Sep. 2022

 

Specimens were collected from the mainstream and tributaries of the Lancang River. n, number of specimens; U, including upper stream of the Lancang River, Jidu River (JDR); M, including middle stream of the Lancang River; WYR, Weiyuan River; HR, Hei River; Down, including downstream of the Lancang River; BYR, Buyuan River, NLR, Nanla River; ○, fishes were collected.

 

Length and weight analyses

Length-weight relationship (LWRs) was calculated using the power function: BW = aSLb

Condition factor was estimated as K = 100 BW / SL3

Relative weight was estimated as Wr = 100 BW / (a SLb)

where BW is the total weight (g), SL is the standard length (cm), a is the intercept of the regression, b is the allometric coefficient and K is the condition factor. Logarithmic transformation was performed and log-log plots of length and weight were used to eliminate outliers prior to the regression analysis of BW on SL as suggested by Froese (2006). Since no outliers were observed in this study, the log-log plots were not provided. Parameters a and b were estimated using linear regression analysis based on 10 logarithms: log BW = log a + b log SL. The 95% confidence limits (Cls) of parameters a and b were estimated. Determination coefficient (r2) calculated from the regression analysis was used to evaluate the fit of LWRs estimate. Besides, the relationship between TL and SL was analysed by linear regression for the TL = p + qSL, where TL is the total length (cm) and p and q is the regression coefficient (Zhang et al., 2017).

Statistical abalysis

T-test suggested by Pauly was performed to estimate the variation of allometric coefficient b with the expected value 3. When the b value does not differ significantly from 3 (p > 0.05), weight growth is considered isometric, indicating that a fish proceeds in the “same” dimension as the cube of length. Otherwise, weight gain is allometric, including positive (b > 3) and negative (b < 3) (Pauly, 1984). All analyses were performed using IBM SPSS Statistics software (version 25.0; SPSS Inc. Ltd.) and Excel (Microsoft Office, 2021) at a significance level of 0.05.

Results

Length and weight analyses

In the present study, 435 specimens belonging to three families, five genera, and seven species were collected. Descriptive statistics and estimated LWRs and LLRs parameters of the seven fish species are listed in Tables II and III. The LWRs for all fish species studied in this study were extremely significant (p < 0.001), with all r2 values over 0.95, indicating that the LWR estimates for all species fit well and highly reliable. The intercept value a ranged between 0.0122 for G. macromaculatus and 0.0335 for S. longibarbata, and the b value ranged from 2.7540 (S. longibarbata) to 3.1038 (G. macromaculatus). All b values remained within the expected range of 2.5 – 3.5 (Forese, 2006). The LWRs for six species were reported for the first time to FishBase, except for O. gerlachi.

 

Table II. Descriptive statistics (Mean±SD, ranges in brackets) and estimated parameters of LWR (BW = a SLb) for seven endemic fish species the Lancang River, Southwest China, from 2018 to 2022.

Species

n

SL (cm)

BW (g)

a

95% Cl of a

b

95% Cl of b

r2

Growth pattern

Garra mirofrontis*

87

9.82 ± 2.74

(5.40-16.50)

25.81 ± 10.64

(3.50-97.70)

0.0244

0.0199-0.0289

2.9576

2.8756-3.0395

0.9845

I

Sikukia longibarbata*

63

11.17 ± 3.87

(5.10-20.00)

33.87 ± 11.89

(4.00-135.40)

0.0335

0.0267-0.0402

2.7540

2.6695-2.8385

0.9858

N

Sikukia flavicaudata*

48

16.68 ± 5.82

(7.40-26.50)

177.35 ± 61.97

(15.00-556.70)

0.0255

0.0152-0.0358

3.0248

2.8795-3.1701

0.9744

I

Onychostoma gerlachi

62

12.24 ± 3.73

(6.60-22.00)

37.28 ± 13.11

(4.10-160.10)

0.0157

0.0120-0.0194

2.9999

2.9044-3.0954

0.9844

I

Schistura kengtungensis*

55

5.31 ± 1.23

(3.50-8.40)

2.71 ± 1.90

(0.80-8.90)

0.0192

0.0156-0.0228

2.8779

2.7642-2.9917

0.9819

I

Glyptothorax macromaculatus*

55

6.69 ± 1.57

(4.00-11.00)

5.30 ± 1.90

(1.00-22.50)

0.0122

0.0088-0.0155

3.1038

2.9590-3.2486

0.9705

I

Glyptothorax zanaensis*

65

6.02 ± 1.21

(4.50-9.70)

3.16 ± 1.23

(1.40-12.50)

0.0196

0.0158-0.0235

2.7699

2.6600-2.8799

0.9771

N

 

n, number of specimens; *, newly recorded LWR to FishBase; bold, new maximum record of standard length to FishBase; n, sample size; S.D., standard deviation; a and b, regression parameters; Cl, confidence limits; r2, coefficient of determination; I, isometric growth; N, negative allometric growth.

 

Table III. Descriptive statistics (Mean±SD, ranges in brackets) and estimated parameters of LLR (TL = p + q SL) for seven endemic fish species sampled in the Lancang River, Southwest China, from 2018 to 2022.

Species

n

TL (cm)

SL (cm)

p

95% Cl of p

q

95% Cl of q

r2

Garra mirofrontis

87

12.60 ± 3.25

(7.00-20.50)

9.82 ± 2.74

(5.40-16.50)

1.0616

0.7451-1.3781

1.1776

1.1466-1.2087

0.9853

Sikukia longibarbata

63

14.20 ± 4.55

(6.50-24.70)

11.17 ± 3.87

(5.10-20.00)

1.1383

0.7587-1.5179

1.1710

1.1388-1.2031

0.9886

Sikukia flavicaudata

48

20.80 ± 7.34

(8.90-33.50)

16.68 ± 5.82

(7.40-26.50)

-0.1231

-0.7715-0.5254

1.2537

1.2170-1.2905

0.9903

Onychostoma gerlachi

62

15.30 ± 4.55

(8.20-27.30)

12.24 ± 3.73

(6.60-22.00)

0.4265

0.1434-0.7096

1.2159

1.1938-1.2381

0.9952

Schistura kengtungensis

55

6.40 ± 1.37

(4.30-9.80)

5.31 ± 1.23

(3.50-8.40)

0.5163

0.3434-0.6892

1.1133

1.0815-1.1450

0.9894

Glyptothorax macromaculatus

55

8.10 ± 1.71

(5.10-13.10)

6.69 ± 1.57

(4.00-11.00)

0.9137

0.6935-1.1339

1.0795

1.0475-1.1116

0.9886

Glyptothorax zanaensis

65

7.23 ± 1.21

(5.50-10.80)

6.02 ± 1.21

(4.50-9.70)

1.3136

1.0237-1.6034

0.9828

0.9355-1.0300

0.9661

 

n, sample size; S.D., standard deviation; p and q, regression parameters; Cl, confidence limits; r2, coefficient of determination.

 

The t-test showed that the b values of S. longibarbata (t = 5.8130, p < 0.05) and G. zanaensis (t = 3.9092, p < 0.05) were significantly less than 3 indicating that these two fish may manifest negative allometric growth pattern. The b values of the other five fish species, namely, G. mirofrontis (t = 1.1999), S. flavicaudata (t = 0.3431), O. gerlachi (t = 0.0411), S. kengtungensis (t = 1.7392), G. macromaculatus (t = 1.5713), were not significantly different from 3 (all p > 0.05). Growth pattern of these five fish could be isometric.

Besides, all LLRs were extremely remarkable (p < 0.001) with all determination coefficient (r2) were > 0.96. This study reported new maximum standard length for three fish species, namely, G. mirofrontis (16.5 cm), S. longibarbata (20.0 cm), and S. flavicaudata (26.5 cm), for the first time to FishBase (Froese and Pauly, 2023).

Condition factor and relative weight

Condition factors of the seven fish species studied in this study ranged from 1.09 to 3.86 (Table IV). The lowest mean condition factor was observed in G. zanaensis, with a mean valve of 1.31±0.11, while the highest mean condition factor was observed in S. flavicaudata, the mean value was 2.77±0.11. The mean relative weight range of the seven fish species was 100.43-101.94 (Table IV), all around 100, indicating a balance between prey availability and predator density of these fish populations in their habitat.

 

Table IV. Condition factors (K) and relative weight (Wr) for seven fish species sampled in the Lancang River, Southwest China, from 2018 to 2022. The values are Mean±SD with ranges in brackets.

Species

n

K

Wr

Garra mirofrontis

87

2.24 ± 0.23

(1.76-2.78)

100.43 ± 10.33

(78.62-125.65)

Sikukia longibarbata

63

1.90 ± 0.29

(1.43-3.02)

100.57 ± 11.69

(73.87-134.39)

Sikukia flavicaudata

48

2.77 ± 0.51

(1.78-3.86)

101.61 ± 18.62

(65.30-142.01)

Onychostoma gerlachi

62

1.58 ± 0.18

(1.24-2.13)

100.44 ± 11.40

(79.05-135.57)

Schistura kengtungensis

55

1.58 ± 0.15

(1.32-1.95)

100.55 ± 9.05

(82.95-124.61)

Glyptothorax macromaculatus

55

1.49 ± 0.20

(1.10-1.84)

100.60 ± 13.15

(74.87-123.14)

Glyptothorax zanaensis

65

1.31 ± 0.11

(1.09-1.54)

100.06 ± 7.85

(85.32-116.40)

 

n, number of specimens; S.D., standard deviation.

 

Discussion

According to the findings of this study, all fish species analyzed showed a strong correlation between length and weight. The r2 value ranged between 0.9705 and 0.9858, indicating that the LWR estimates for all species fit well and were highly reliable. Although the sample size of several fish specimens used in this study is small, all b values remained within the expected range of 2.5-3.5 (Forese, 2006). According to the comparison of this b value with 3, growth pattern of fishes can be discussed. However, the parameter b is species-specific (Borah et al., 2018), and some other factors would affect the b parameter, for example, sex (Compaire and Soriuer, 2020), size classes (Zambrano et al., 2023), different time periods (Sun et al., 2019; Douligeri et al., 2023), or even different geographic populations (Singh and Serajuddin, 2017). To increase the reliability of discussing isometric versus allometric growth of the species as a whole, based on mean b, all factors affect length-weight estimates should be considered and geographic, seasonal, and inter-annual variation should be covered reasonably (Forese, 2006).

Condition factor (K), also called Fulton condition factor, is an extended index of length and weight that reflects the development and nutritional status of fish at the individual level (Dai et al., 2006; Rypel and Layman, 2008). When fishes are of the same body length, the larger their body masses, the better their physiological and nutritional status, and the higher their condition factor (Jones et al., 1999). The Fulton condition factor is proposed under the ideal assumption that an animal’s expected body weight grows evenly with its body length. In the present study, except for S. longibarbata and G. zanaensis, the b values of the other five fish species were not significantly different from 3, conforming to the assumption. However, for most animals, including fishes, weight growth does not proceed in the “same” dimension as the cube of length (Dai et al., 2006). Besides, condition factor is closely related to age, gender, environment condition, season, population density, inter-specific and intra-specific relationships (Forese, 2006; Haberle et al., 2023), all aforementioned factors should be considered to evaluate the condition factor more reliable.

The mean relative weight for all fish species studied in this study all around 100, indicating a balance between prey availability and predator density of these fish populations in their habitat. According to Anderson and Neumann (1996), if relative weight (Wr) of an individual or population less than 100 may indicate problems, such as low prey availability or high predation pressure; while the relative weight (Wr) greater than 100 indicates sufficient prey or low predation pressure.

Conclusion

According to the information in FishBase, this paper not only reports the LWRs and LLRs for six fish species (except for O. gerlachi) in the Lancang River basin for the first time, but also records new maximum standard length of three species, namely, G. mirofrontis, S. longibarbata, and S. flavicaudata. However, the sampling did not include sufficiently broad temporal and spatial scope making the results unrepresentative. Moreover, gender, gonad maturity, development stages, gut satiety were not considered in this study, which may also make inconclusive of LWRs, LLRs, condition factor and relative weight. Although it cannot fully represent the entire population, the preliminary estimated LWRs, LLRs, condition factor and relative weight were useful. It provided basic data of fish biology for seven endemic fish species in Lancang River, Yunnan province, China, which will be of value of reference for subsequent research and management of these species.

Declarations

Acknowledgement

We are grateful to Xiu Ling Chang, Lei Liang, and Zhan Chao Yin of Institute of Hydroecology, Wuhan, China, for their assistance in sample collection.

Funding

We thank the Scientific Research Foundation of Wuhan Polytechnic University, Study on the Sustainable Impact of Hydropower Development on Environment in the Main Stream of Lancang River (Wulonglong-Nana Estuary Section) [HY2021/S17-1] and the National Natural Science Foundation of China [NSFC-31800391] for their support.

Statement of conflict of interest

The authors have declared no conflict of interest.

References

Anderson, R.O. and Neumann, R.M., 1996. Length, weight and associated structural indices. In: Fisheries techniques, 2 nd edn. (ed. B.R. Murphy, D.W. Willis). American Fisheries Society, Maryland, pp. 447-482.

Borah, S., Gogoi, P., Bhattacharjya, B.K., Suresh, V.R., Yadav, A.K., Baitha, R. Koushlesh, S.K., Kakati, A., Ray, B.C. and Das, B.K., 2018. Length–weight and length-length relationship of two endemic snakehead fish species from Brahmaputra river basin, Assam, India. J. appl. Ichthyol., 34: 788-790. https://doi.org/10.1111/jai.13685

Chen, X.Y., 2013. Checklist of fishes of Yunnan. Zool. Res., 34: 281-343. (in Chinese with English abstract)

Chu, X.L. and Chen, Y.R., 1989. The fishes of Yunnan, China. Part 1: Cyprinidae. Science Press, Beijing, China. (in Chinese)

Chu, X.L. and Chen, Y.R., 1990. The fishes of Yunnan, China. Part 2, Science Press, Beijing, China. (in Chinese).

Çiçek, E., Seçer, B., Sungur, S., Öztürk, S. and Bahçeci, H., 2022. Length–weight relationships and condition factors of 28 fish species belonging to Leuciscidae (Cypriniformes) from Turkey, J. appl. Ichthyol., 38: 364-367. https://doi.org/10.1111/jai.14315

Compaire, J.C. and Soriuer, M.C., 2020. Length–weight relationships of seven fish species from tidepools of an intertidal rocky shore in the Gulf of Cadiz, Spain (NE Atlantic). J. appl. Ichthyol., 36: 852-854. https://doi.org/10.1111/jai.14087

Dai, Q., Dai, J.H., Li, C., Liu, Z.J. and Wang, Y.Z., 2006. Discussion on relative fatness. Chinese J. appl. environ. Biol., 12: 715-718. (in Chinese with English abstract).

Douligeri, A.S., Ziou, A., Korakis, A., Kiriazis, N., Petsis, N., Katselis, G. and Moutopoulos, D.K., 2023. Notes on the summer life history traits of the non–native pumpkinseed (Lepomis gibbosus) (Linnaeus, 1758) in a high–altitude artificial lake, Diversity, 15: 910. https://doi.org/10.3390/d15080910

Froese, R. and Pauly, D., 2023. FishBase, Version10/2023. http://www.fishbase.org.

Froese, R., 2006. Cube law, condition factor and weight length relationship: History, meta–analysis and recommendations, J. appl. Ichthyol., 22: 241-253. https://doi.org/10.1111/j.1439-0426.2006.00805.x

Haberle, I., Bavčević, L.V. and Klanjscek, T., 2023. Fish condition as an indicator of stock status: Insights from condition index in a food−limiting environment. Fish. Fish., 24: 567-581. https://doi.org/10.1111/faf.12744

Hong, Y.X., Shi, W.Q., Chen, Y.C., Liu, D.S., Ma, H.H., Zhu, H.Y. and Chen, Q.W., 2021. Succession of fish community in the mainstream of Lancang River during cascade hydropower development. Acta Ecol. Sin., 41: 235-253. (in Chinese with English abstract). https://doi.org/10.5846/stxb201910182186

Jones, R.E., Petrell, R.J. and Pauly, D., 1999. Using modified length-weight relationships to assess the condition of fish. Aquacult. Eng., 20: 261-276. https://doi.org/10.1016/S0144-8609(99)00020-5

Le Cren, E.D., 1951. The length weight relationship and seasonal cycle in gonad weight and condition in perch (Perca fluviatilis). J. Anim. Ecol., 20: 12-16. https://doi.org/10.2307/1540

Li, J.P., Dong, S.K., Peng, M.C., Yang, Z.F., Liu, S.L., Li, X.Y. and Zhao, C., 2013. Effects of damming on the biological integrity of fish assemblages in the middle Lancang-Mekong River basin. Ecol. Indic., 34: 94-102. https://doi.org/10.1016/j.ecolind.2013.04.016

Li, X.Q., Sun, H.Y., He, D.K. and Chen, Y.F., 2019. Freshwater fish diversity in the upper and middle reaches of the Lancang-Mekong River. Biodiv. Sci., 27: 1090-1100. (in Chinese with English abstract). https://doi.org/10.17520/biods.2019195

Lizama, M., De Los, A.P. and Ambrósio, A.M., 2002. Condition factor in nine species of fish of the Characidae family in the upper Paraná river floodplain, Brazil. Brazil. J. Biol., 62: 113-124. https://doi.org/10.1590/S1519-69842002000100014

Ngor, P.B., Legendre, P., Oberdorff, T. and Lek, S., 2018. Flow alterations by dams shaped fish assemblage dynamics in the complex Mekong-3S river system. Ecol. Indic., 88: 103-114. https://doi.org/10.1016/j.ecolind.2018.01.023

Patrick, A.E.S., Kuganathan, S. and Edirisinghe, U., 2021. Length-weight relationships and growth patterns of local fishes of the medium perennial vavuniya reservoir, Sri Lanka. Pakistan J. Zool., 53: 1291-1299. https://doi.org/10.17582/journal.pjz/20181106161128

Pauly, D., 1984. Fish population dynamics in tropical waters: A manual for use with programmable calculators. International Center for Living Aquatic Resources Management, Manila, Philippines, pp. 5-8.

Rainboth, W.J., Vidthayanon, C. and Mai, D.Y., 2012. Fishes of the Greater Mekong ecosystem with species list and photographic atlas, Miscellaneous Publications, Ann Arbor, USA.

Rypel, A.L. and Layman, C.A., 2008. Degree of aquatic ecosystem fragmentation predicts population characteristics of gray snapper (Lutjanus griseus) in Caribbean tidal creeks, Can. J. Fish. aquat. Sci., 65: 335-339. https://doi.org/10.1139/f07-192

Rypel, A.L., Bayne, D.R. and Mitchell, J.B., 2006. Growth of freshwater drum from lotic and lentic habitats in Alabama. Trans. Am. Fish. Soc., 135: 987-997. https://doi.org/10.1577/T05-126.1

Singh, M. and Serajuddin, M., 2017. Length-weight, length-length relationship and condition factor of Channa punctatus collected from three different rivers of India. J. Ent. Zool. Stud., 5: 191-197.

Stevenson, R.D. and Woods, W.A., 2006. Condition indices for conservation: New uses for evolving tools. Integr. comp. Biol., 46: 1169-1190. https://doi.org/10.1093/icb/icl052

Sun, L.T., Zhao, F., Wang, S.K., Wang, Y., Yang, G. and Zhuang, P., 2019. Growth and feeding ecology of juvenile Chinese sturgeon, Acipenser sinensis, in the Yangtze Estuary. J. appl. Ichthyol., 35: 47-53. https://doi.org/10.1111/jai.13835

Zambrano, M.J., Bonifacio, A.F., Brito, J.M., Rautenberg, G.E. and Hued, A.C., 2023. Length-weight relationships and body condition indices of a South American bioindicator, the native neotropical fish species, Cnesterodon decemmaculatus (Poeciliidae). J. Ichthyol., 63: 930-936. https://doi.org/10.1134/S0032945223050156

Zhang, C., Ding, L. Y., Ding, C. Z. Chen, L. Q., Sun, J., and Jiang X., 2018. Responses of species and phylogenetic diversity of fish communities in the Lancang River to hydropower development and exotic invasions. Ecol. Indic., 90: 261-279. https://doi.org/10.1016/j.ecolind.2018.03.004

Zhang, Z., Ding, H., Wang, W., Chen, F., Huang, D. and Yang, Z., 2017. Length-weight and length-length relationships of four fish species from the middle reaches of the Minjiang River, southwest China. J. appl. Ichthyol., 33: 1296-1298. https://doi.org/10.1111/jai.13483