The length-weight relationships (LWRs) of six fish species from the central and southern South China Sea are presented in this study. A total of 359 specimens were collected by light falling nets (20~36 mm mesh size) in 2012. The b values of the LWR equations varied between 2.670 and 3.265 for the studied species. As a supplement to LWR data, it is the first time that relevant data from this sea area have been provided to fish base.
Short Communication · Volume 54, Issue 3, 7 March 2022 · Open Access
Length-weight Relationship of Six Fish Species from the Central and Southern South China Sea
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Affiliations & Notes ⌄
- 1Third Institute of Oceanography, Ministry of Natural Resources, Xiamen 361005, China * Corresponding author: linlsh@tio.org.cn
Article Info ⌄
- Journal:
- Pakistan Journal of Zoology
- Published:
- 7 March 2022
From the article
- Our research provided the LWR data for six fish species from the central and southern South China Sea, and data collected from this sea area was not previously available in the Fish Base database.
- The SL and TW ranges and LWR parameters are given in Table I. In the present study, six fish species had coefficient of determination (r2) values, that ranged from 0.873 to 0.978.
- The r2 values of the LWRs of all fish species exceeded 0.95, except C. equiselis, which had an r 2 value less than 0.9.
Selected from the article's own text.
Abstract
Materials and methods
The studied area was located in the marine area between 5°30′~16°00′N and 109°00′~117°30′E. All specimens were collected from commercial fishing boats using light falling nets (20~36 mm mesh size) operated to a depth of 50~70 m. All specimens were identified to the species level according to Cheng et al. (1962) and Nelson (2006). A total of 359 specimens of six fish species were collected and used to estimate their LWRs. The numbers of specimens were given in Table I and varied from 25 to 116. The standard length (SL) for each species was measured as the distance from the tip of the snout to the base of the caudal fin. SL was measured to 0.1 cm, and the total weight (TW) was measured to 1 g. The LWRs, W = aLb, were log-transformed into a linear equation: log (W)= log (a)+ b log (L), where W is total weight (g), L is the standard length (cm), a is the intercept and b is the slope ; . Obvious outliers were identified and eliminated from the linear regression analyses, and the optimal regression parameters a and b were estimated by least squares estimation ; .
Results and discussion
Our research provided the LWR data for six fish species from the central and southern South China Sea, and data collected from this sea area was not previously available in the Fish Base database. The SL and TW ranges and LWR parameters are given in Table I. In the present study, six fish species had coefficient of determination (r2) values, that ranged from 0.873 to 0.978. Parameter b varied from 2.670 for C. equiselis to 3.265 for K. pelamis.
The b values of all six fish species fell within the expected range between 2.5 and 3.5, as proposed by Froese (2006). The r2 values of the LWRs of all fish species exceeded 0.95, except C. equiselis, which had an r 2 value less than 0.9. This result may be attributable to the small
Table I. Descriptive statistics and parameters of the LWRs for six fish species from the central and southern South China Sea.
| SL range (cm) | TW range (g) | Length-weight relationships (LWRs) | |||||||||
| Family | Species | N | Min | Max | Min | Max | a | b | r2 | 95% CI (a) | 95% CI (b) |
| Bramidae | Brama japonica Hilgendorf, 1878 | 99 | 13.0 | 34.6 | 47 | 870 | 0.0406 | 2.827 | 0.978 | 0.0315-0.0525 | 2.742-2.912 |
| Coryphaenidae | Coryphaena equiselis Linnaeus, 1758 | 44 | 21.2 | 29.8 | 145 | 397 | 0.0425 | 2.670 | 0.873 | 0.0153-0.1181 | 2.353-2.987 |
| Carangidae | Decapterus macrosoma Bleeker, 1851 | 48 | 15.3 | 27.5 | 46 | 287 | 0.0076 | 3.180 | 0.951 | 0.0039-0.0151 | 2.967-3.394 |
| Scombridae | Auxis rochei (Risso, 1810) | 27 | 22.7 | 25.6 | 172 | 253 | 0.0069 | 3.241 | 0.953 | 0.0027-0.0176 | 2.945-3.537 |
| Scombridae | Katsuwonus pelamis (Linnaeus, 1758) | 116 | 28.7 | 48.0 | 365 | 2240 | 0.0074 | 3.265 | 0.955 | 0.0046-0.0119 | 3.134-3.395 |
| Scombridae | Thunnus albacares (Bonnaterre, 1788) | 25 | 33.7 | 45.8 | 815 | 1880 | 0.0635 | 2.690 | 0.964 | 0.0275-0.1465 | 2.466-2.915 |
N, number of individuals; SL range, standard length range; TW range, total weight range; a, intercept; b, slope; r2, coefficient of determination; CI, confidence interval.
to medium sample size . Due to the limited duration of sampling, the larger size classes were missing, and the growth patterns of the specimens could not be fully reflected. In addition, gender information is lacking in the sample data, so it was difficult to describe sexual variability. We will create a more reasonable sampling plan with a lengthened sample period and increased sample size and provide a gender distinction in further research. Our results can provide basic information for the management and conservation of the investigated species.
Acknowledgements
The research was funded by the National Programme on Global Change and Air-Sea Interaction (GASI-02-SCS-YSWspr/aut/. The authors declare that they have no conflicts of interest to this work.
Statement of conflict of interest
The authors declare there is no conflict of interest.
References
- Cheng, Q., Zhu, Y. and Zhang, C., 1962. Fishes of South China Sea. Science Press. Beijing (in Chinese)
- Froese, R., 2006. J. appl. Ichthyol., 22: 241–253. https://doi.org/10.1111/j.1439-0426.2006.00805.x[CrossRef]
- Kwun, H.J., Park, J., Kim, H.S., Bae, H. and Jeong, S.J., 2017. J. appl. Ichthyol., 33: 1229–1230. https://doi.org/10.1111/jai.13400[CrossRef]
- Lleonart, J., Salat, J. and Torres, G.J. 2000. J. Theor. Biol., 205: 85–93. https://doi.org/10.1006/jtbi.2000.2043[CrossRef]
- Nelson, J.S., 2006. Fishes of the world (4th ed.). John Wiley and Sons, Inc. New York
- Zhan, B.Y., 1995. Fish stock assessment (1st ed). Beijing: China Agriculture Press. (in Chinese)
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