Phenotypic variation and relationships in body weight and composition traits of domesticated snakeskin gourami (Trichopodus pectoralis) at harvest

doi:10.21203/rs.3.rs-4166071/v1

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Phenotypic variation and relationships in body weight and composition traits of domesticated snakeskin gourami (Trichopodus pectoralis) at harvest

https://doi.org/10.21203/rs.3.rs-4166071/v1

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Phenotypic variation in organisms arises from diverse sources, each with unique implications for adaptability to selection and environmental changes. This variation is particularly significant in tropical aquaculture, exemplified by the snakeskin gourami (Trichopodus pectoralis), a popular whole-body sale fish. Understanding these variations is crucial for optimizing animal breeding and commercialization efforts. This study explores previously uncharted territory by investigating the relationships among body weight (BW), total length (TL), body depth (BD), and Fulton’s condition factor (K) using 8,345 records of domesticated snakeskin gourami fish at the 9-month harvest point. Interrelationships between these traits and the associations between BW and other characteristics were examined and compared for each sex. Sexual dimorphism was evident, with females being significantly more extensive, and it showed higher variation and a stronger correlation between traits than males in all characteristics. The population was categorized into six market sizes (XL, L, M, S, XS, and XXS), with XXS being the most abundant (36.35%), followed by XS, S, M, L, and XL (31.95%, 23.30%, 8.06%, 0.31%, and 0.04%, respectively). There was mostly a male population in the XS and XXS size categories compared to a female population. Strongly significant correlations emerged (p < 0.0001), with BW highly associated with TL and BD and moderately associated with K. This study underscores the importance of understanding sexual dimorphism and trait correlations in domesticated snakeskin gourami for informing selective breeding and commercial strategies in tropical aquaculture.

Snakeskin gourami

Phenotypic variation

Body weight

Body composition traits

Tropics

Snakeskin gourami (Trichopodus pectoralis) is a tropical aquatic fish species native to Thailand, Cambodia, Vietnam, and Laos, with introductions into Indonesia, Malaysia, and Singapore (Gan et al. 2017; Ahmadi 2021). Global snakeskin gourami production reached approximately 30,500 t in 2021 (FAO 2023). Notably, Thailand has cultivated snakeskin gourami for over six decades (Indrambarya 1980), emerging as a critical player in the niche market, ranking fifth in freshwater fish production (DOF 2022). The financial cost-benefit analysis of snakeskin gourami culturing has improved from approximately 13% (Chesoh 1995) to 58% (DOF 2021). There are local and global trades for frozen fish, chilled fish, juvenile fish, and aquarium fish, and most consumers know processed salted-sundried fish (DOF 2022) due to its tasty meat (Vromant et al. 2001) and long-lasting preservation (Waiprib et al. 2016). The snakeskin gourami boasts a comparatively higher market value than other tropical aquaculture species (Gustiano et al. 2022). In Thailand, fresh snakeskin gourami price in 2023 (USD 1.6–2.7/kg) is higher than Nile tilapia (Oreochromis niloticus; USD 1.6–2.0/kg) and broadhead catfish (Clarias macrocephalus; USD 1.1–1.4/kg). Meanwhile, the retail price of large-size, salted-sundried fish can be sold up to almost four times the fresh price (USD 7.1–10.0/kg) (Talaad Thai 2024).

Similar to other aquatic species, snakeskin gourami, a whole-body sale fish, has consumer preferences beyond body weight (BW) and total length (TL), including body shape aspects like body depth (BD) (Joshi et al. 2021) or maximum body height (Gayo et al. 2023) and condition factor (K) (Srimai et al. 2020). Consumers favor snakeskin gourami's rounded/plump body shape, particularly emphasizing BD and TL as two critical dimensions. As a relationship between BW and TL (K = 100 BW/TL³; Fulton 1904), Fulton’s condition factor helps detect variations in weight from the expected values based on length. These variations can indicate the fish's overall health, well-being, or fitness (Teubner et al. 2015) and body shape (flat/thin and rounded/plump) (Firdaus et al. 2018). However, Ragheb (2023) suggested that the study of K assesses differences between species due to variations in fish shape and proposed that each fish family has its own range depending on the fish shape, and (K > 1) is not necessarily a better condition for the fish. While various studies have delved into different biological and physiological aspects of snakeskin gourami, covering topics from morphological development (Morioka et al. 2010) to genetic characterizations (Gustiano et al. 2022), comprehensive analyses of variation, correlation, and regression patterns concerning BW and composition traits within domesticated populations have been notably absent. Phenotypic variation arises from diverse sources, each carrying distinct underlying causes (Graham 2021). Understanding the origins of phenotypic variation is vital to gauging a trait's responsiveness to natural or artificial selection and its adaptability to environmental changes (Naval-Sanchez et al. 2020), a pivotal concern for academic inquiry. This knowledge empowers researchers to forecast population-level evolutionary dynamics concerning specific features (Lickliter 2013).

The present study addresses a critical research gap by investigating the previously unreported variations and relationships among BW, TL, BD, and K in domesticated snakeskin gourami at the 9-month harvest point. It evaluates correlations and regression patterns across sexes, offering insights into the intricate interplay of BW with TL, BD, and K. Moreover, the study highlights the significance of K as an indicator of fish health and shape, bridging the gap between biotic and abiotic factors affecting fish characteristics. Ultimately, this research will enhance our understanding of the relationship between BW and various harvest traits, as well as K, as a valuable resource for future fish population studies and stock assessments (Ragheb 2023). Furthermore, the market only categorized salted-sundried snakeskin gourami, while fresh snakeskin gourami was inaccessible. The primary objective of this study is to enhance our comprehension of the complex relationship between BW and various body composition traits in tropical domesticated snakeskin gourami at the 9-month harvest point. This research provides valuable insights into the dynamics between BW and other pivotal harvest traits by meticulously examining variations, correlations, relationships, and Fulton’s condition factor (K).

Experimental fish population

A comprehensive dataset comprising 8,345 records of farmed snakeskin gourami population data was collected at harvest, occurring 270 days after hatching (DAH) (9 months). This data spans multiple generations, with the baseline population (G₀) conducted from April 2018 to January 2019, the first generation (G₁) implemented between September 2020 and June 2021, and the second generation (G₂) from October 2021 to July 2022. The research was conducted at two locations: (1) the Department of Aquaculture, Faculty of Fisheries, Kasetsart University, located in Bangkok, and (2) the Kamphaeng Sean Fisheries Station, Kasetsart University, Kamphaeng Sean Campus, in Nakhon Pathom province, Thailand.

Production, nursing, and grow-out of fish

The breeding process started with selected broodstock, where males and females were separated into different cages and reared until fully mature. The brooders were chosen for breeding based on their readiness to spawn (e.g., soft and swelling bellies and enhanced roughness of tubercles on the gill operculum). Then, the selected brooders were administered 1000 IU/kg of human chorionic gonadotropin (hCG) hormone before being placed in a 300 L breeding cylindrical tank at a 1:1 sex ratio to facilitate natural spawning. After initial mating, males were sequentially paired with different females to establish full-sib and paternal half-sib families.

After successful spawning, the mating pairs were removed, and the fertilized eggs were left to hatch. On day 3, after hatching, the larvae started feeding following the feeding regime described in the later section. Subsequently, approximately 1,000 fish were randomly collected from each family, and individual families were reared in 300 L cylindrical tanks until they reached 15 DAH. These fish were later transferred to three separate cages, each measuring 1 × 1 m² with a depth of 1 m, stocking 150 fish per cage. The cages were installed in earthen ponds equipped with a flow-through water system. The fish were reared in these cages and tagged at 120 DAH. These tagged fish were then randomly stocked in cages, each measuring 5 × 5 m² with a depth of 2 m, fixed in a 0.32-hectare earthen pond supplied with flow-through water at 15 fish/m² density. These fish were consistently fed a commercially available diet until they reached the harvesting age of 270 DAH.

Feeding commenced after the complete absorption of the yolk sac. Initially, the fry was nourished with an egg-yolk solution from days 3–7 DAH. Subsequently, they were transitioned to Moina spp. from 5–10 DAH, followed by fish meal containing 60% protein from days 8–15 DAH, and small-sized commercial pelleted feed with 40% protein (Higrade 9961, Charoen Pokphand Foods Public Company Ltd., Samut Sakhon, Thailand) from days 13–60 DAH. From 60 DAH until the harvest at 270 DAH, the fish were fed a 30% protein pelleted feed designed for snakeskin gourami (Betagro 811, Betagro Co. Ltd., Lopburi, Thailand), amounting to 3% of their BW.

Data collection

Data collection involved three measurement sessions: following tagging, after transferring to the new cages, and at the time of harvest (at 120, 255, and 270 DAH, respectively). However, only the data from the harvest session was utilized in this research. Fish sex was determined primarily through external morphology at harvest, relying on distinct characteristics as depicted in Fig. 1. Males exhibited pointed and elongated fin tips extending to the caudal peduncle, accompanied by tubercles on the caudal peduncle. In contrast, females exhibited shorted and rounded fin tips (Chatchaiphan et al. 2019; Boonanuntanasarn et al. 2020).

Measurements included TL, recorded to the nearest centimeter, and BW, recorded to the nearest gram, as illustrated in Fig. 2. Body shape traits, including BD, were assessed through individual fish photographs using a digital camera and analyzed using the GNU Image Manipulation Program (Kimball et al. 2023), enabling precise centimeter-based measurements (Sutthakiet et al. 2020). The K was calculated employing Fulton's formula (Fulton 1904): K = (BW × 100)/TL³).

Classification of snakeskin gourami sizing

In the context of market classification, fresh snakeskin gourami is systematically categorized based on weight per kilogram into distinct size categories, as shown in Table 1, modified from Yensuk (2005). The XXL size encompasses specimens numbering 3–4 fish/kg, each weighing at least 250 g. The XL size comprises relatively smaller fish, including 4–5 fish/kg, typically ranging from 200 g to just under 250 g. The L size represents snakeskin gourami weighing 5–6 fish/kg, with weights falling from 167–200 g. Moving to smaller dimensions, the M size pertains to specimens numbering 6–9 fish/kg, with individual weights spanning from 111–167 g. Further down the size spectrum, the S size encompasses individuals weighing 9–12 fish/kg, weighing between 83 g and 111 g. The XS size consists of 12–16 fish/kg, with their weights within the range of 62 g to just under 83 g. Lastly, the XXS size relates to snakeskin gourami that weigh above 16 fish/kg, with each fish weighing less than 62 g. This classification system is integral to the research methodology and data analysis.

Table 1

The market classification of snakeskin gourami was modified from Yensuk (2005)
Size categories	Number of fish/kg	Size range
XXL	3–4	> 250 g
XL	4–5	> 200–250 g
L	5–6	> 167–200 g
M	6–9	> 111–167 g
S	9–12	> 83–111 g
XS	12–16	≥ 62–83 g
XXS	> 16	< 62 g

Statistical analyses

All data on BW, TL, BD, and K underwent a series of statistical analyses. Initially, normality tests were conducted to assess the distribution of the data. Descriptive statistics were computed for all traits. Analysis of variance and multiple comparisons using the Bonferroni post hoc test of each trait were then applied to explore the influence of sex. The results, presented as least squares mean (LSmeans) ± standard error (SE), offer a clear and scientifically robust understanding of the variables studied. Pearson’s correlation coefficients among these traits were computed to evaluate their interrelationships. All tests were analyzed at the 95% significance level. SAS software was used for all data analysis (SAS 2011).

Characteristic of the snakeskin gourami population

Our study encompassed 8,345 individual snakeskin gourami, including 3,344 males and 5,001 females, distributed across 252 full-sib families, consisting of 179 sires and 219 dams, spanning three generations. Notably, the observed survival rate stood at an average of 71.57%±20.16%. The sex ratio skewed towards females at a ratio of 1:1.5. Detailed metrics of the overall snakeskin gourami's physical traits revealed significant variations. BW ranged from 12.00–203.56 g, with a mean of 73.08 ± 26.64 g. TL spanned from 9.80–22.53 cm, averaging 16.45 ± 1.72 cm, while BD ranged from 2.66–8.71 cm, with an average of 5.41 ± 0.88 cm. The K ranged from 0.73–2.96, averaging 1.57 ± 0.26. Females have a slightly wider range of BW (12.50–203.95 g) and BD (2.66–8.71 cm) compared to males (BW: 12.00–201.95 g and BD: 2.66–7.93 cm, respectively). While males have a slightly broader range of TL (9.88–21.83 cm) and K (0.77–2.89) than females (TL: 9.80–21.73 cm and K: 0.73–2.70, respectively).

The LS means of males and females exhibited all measured traits at harvest in Table 2. BW of females (74.79 ± 0.31 g) was significantly larger than males (56.34 ± 0.38 g, p < 0.0001). The TL of the females (16.40 ± 0.02 cm) was significantly longer than that of the males (15.78 ± 0.02 cm, p < 0.0001). The BD and K of males exhibited a significantly narrower shape (4.90 ± 0.01 cm and 1.39 ± 0.01, respectively; p < 0.0001) compared to females (5.43 ± 0.01 cm and 1.60 ± 0.01, respectively; p < 0.0001).

Table 2

The least square means ± standard error of body weight (BW), total length (TL), body depth (BD), and condition factor (K) at harvest of all sex, male and female snakeskin gourami.
Traits	N	Male	N	Female	p-value
BW (g)	3344	56.34 ± 0.38	5001	74.79 ± 0.31	p < 0.0001
TL (cm)	3241	15.78 ± 0.02	4909	16.40 ± 0.02	p < 0.0001
BD (cm)	3190	4.90 ± 0.01	4809	5.43 ± 0.01	p < 0.0001
K	3241	1.39 ± 0.01	4909	1.60 ± 0.01	p < 0.0001

The snakeskin gourami population, harvested at nine months, was classified into six market sizes (XL, L, M, S, XS, and XXS), as depicted in Fig. 3. Despite the relatively shorter cultivation period of 9 months and under the experimental condition compared to traditional practices, which lasted 12–13 months, the BW distribution spanned a wide range. The most abundant size category was XXS, constituting 36.35% of the population, potentially serving for further growth in separate ponds or processing. The males accounted for 50.51% of the entire male population, while the females accounted for 26.87%. XS-sized individuals, comprising 31.95% of the population, were suitable for salted-sundried fish production. There were 34.99% of the male population and 29.91% of the female population. S-sized individuals accounted for 23.30%, and M-sized for 8.06% of the population. The S-sized category accounts for most females, accounting for 30.59%. This percentage was twice as high as that of men who wore this size, 12.38%. Simultaneously, females comprised 12.08% of the M-sized population, while males comprised 2.06%. Notably, substantial profits for farmers often commenced with the L size (0.31% of the population), while the XL size constituted 0.04% of the population, commanding premium prices.

Relationship between the measured harvest traits

The comprehensive analysis revealed significant positive correlations among all measured traits across both sexes, ranging from 0.21–0.89 (Table 3). The results indicated significant positive correlations between BW and both TL and BD (0.89 and 0.83, p < 0.0001). This implies that fish with greater BW tend to exhibit greater values regarding TL and BD. A statistically significant correlation (0.58, p < 0.0001) was observed between BW and K, indicating that animals with a larger BW tend to have a higher K. A strong positive connection between TL and BD (0.79, p < 0.0001) was also observed, indicating that deeper fish are likely to have a longer TL. Conversely, this information could be valuable in understanding the K of the fish. Moderate positive correlations with both TL and BD (0.21 and 0.48, p < 0.0001) were found in this study, suggesting that an increase in these dimensions corresponds to an elevation in K. These observations significantly enhance our comprehension of the intricate interrelationships among these traits within the snakeskin gourami population.

Table 3

Phenotypic correlations and p-value among body weight (BW), total length (TL), body depth (BD), and condition factor (K) at harvest in all sexes of snakeskin gourami.
Traits	TL (cm)	BD (cm)	K
BW (g)	0.89 (p < 0.0001)	0.83 (p < 0.0001)	0.58 (p < 0.0001)
TL (cm)		0.79 (p < 0.0001)	0.21 (p < 0.0001)
BD (cm)			0.48 (p < 0.0001)

From Table 4 and Fig. 4, when analyzing male snakeskin gourami, significant positive correlations (0.03–0.87) among traits were observed, except for the correlation between K and TL. Scatter plots (Fig. 4) showed that relationships between females BW and other harvest traits were more widely distributed than between males. Particularly, male BW exhibited a significantly positive high correlation with TL (0.87, p < 0.0001) and BD (0.78, p < 0.0001) and a moderately positive correlation with K (0.48, p < 0.0001). In contrast, female BW exhibited a higher range of moderate to high positive correlations with TL, BD, and K (0.92, 0.84, and 0.56, respectively; p < 0.0001). Conversely, the correlation between TL and BD was significantly high in both males and females (0.73 and 0.81, respectively; p < 0.0001). Furthermore, there was a moderate correlation between BD and K (0.36 for males and 0.48 for females; p < 0.0001). The connection between TL and K was low and non-significant (0.03) in males and significant (0.26, p < 0.0001) in females. These correlations were notably stronger in females than in males.

Table 4

Pearson correlation matrix and p-value for body weight (BW), total length (TL), body depth (BD), and condition factor (K) at harvest, differentiated by gender (male in the upper diagonal and female in the lower diagonal).
Traits	BW (g)	TL (cm)	BD (cm)	K
BW (g)		0.87 (p < 0.0001)	0.78 (p < 0.0001)	0.48 (p < 0.0001)
TL (cm)	0.92 (p < 0.0001)		0.73 (p < 0.0001)	0.03 (p = 0.0624)
BD (cm)	0.84 (p < 0.0001)	0.81 (p < 0.0001)		0.36 (p < 0.0001)
K	0.56 (p < 0.0001)	0.26 (p < 0.0001)	0.48 (p < 0.0001)

The size of the harvested snakeskin gourami in our study, ranging from 13–14 fish per kilogram, aligns with the previous report (Chatchaiphan et al. (2019) given under similar conditions. This disparity can be attributed to our higher stocking density (15 fish/m²) compared to the more typical 3–5 fish/m² used in commercial ponds (Sampantarak et al. 2004; Tipbunpot et al. 2005). However, it notably differs from commercially cultured fish, which typically range from 5–6 fish per kilogram, and from wild populations, as reported by Ahmadi (2021). It's worth noting that farmers have observed size differences between male and female populations. While female populations are generally more desirable and productive, sexual size dimorphism has emerged as an economically important trait (Boonanuntanasarn et al. 2020; Nakharuthai et al. 2022). The skewed sex ratio observed in this snakeskin gourami population mirrors findings reported by Chatchaiphan et al. (2019) and Nakharuthai et al. (2022), indicating a predominance of females within the population. Furthermore, this population was reared under experimental conditions and harvested at 9 months old. The expected snakeskin gourami market size ranged from XL to XS categories, depending on what product they would process, such as crispy fried fish, seasoning mixed snacks, and salted-sundried fish (Waiprib et al. 2016). Additionally, it's worth noting that salted-sundried fish typically lose around 40–50% of their fresh weight during processing, as reported by Waiprib et al. (2016) and Rabob et al. (2020).

There was more significant variation among BW and various harvest traits in females than males. Behavioral interactions and nutritional factors influence size variation in snakeskin gourami. Improved culture conditions can reduce the need for stressful and labor-intensive grading operations (Perera et al. 2021). However, it is essential to recognize that size distributions can be activated in favorable environments and may not be directly comparable due to differences in management and timing. Interestingly, the BW distribution of snakeskin gourami reported in wild populations from Indonesia exhibited a similar pattern (Ahmadi 2021). The distribution graph of BW encompassed a wide range of sizes, suggesting the potential of producing robust growth offspring by simple selection.

Nevertheless, phenotypic variation for individuals in a population is due to environmental and genetic factors and the interactions or associations between these factors (Falconer and Mackay 1996). Moreover, it remains essential to continue collecting data from the following generations and provide clear pedigree information to simplify the execution of genetic evaluation and the estimation of genetic parameters, such as heritability and genetic correlation. Heritability is especially a measure of how much of the phenotypic variance is described by the additive genetic variance. This evaluation is crucial when considering selective breeding programs, as it predicts a population’s responsiveness to the selection according to the estimated breeding value (Gjedrem and Baranski 2009).

The relationship between BW was moderate to highly correlated with various body composition traits in this domesticated snakeskin gourami population. Especially females displayed significantly greater relationships with these variables than males. Moreover, females show various types of body shapes, such as a narrow shape (long TL with a small BD) and a plump shape (long TL with a wide BD). Fish growth tends to be correlated with body size. As fish grow, they generally increase in weight, length, and depth. This pattern can lead to strong correlations between BW and other size-related measurements. These findings suggest that BD, given its strong correlation with BW and moderate correlation with K, could be a crucial criterion for future selective breeding programs.

Fulton’s condition factor is proportional to weight and length as an indicator of the health, well-being, fitness (Teubner et al. 2015), and body shape (Firdaus et al. 2018) of the fish. The larger the factor, the better the condition. It was determined by factors such as feed availability, stocking density, parasitic infestations, and environmental conditions. The overall K result from this study ranged from 0.73–2.96 with an average of 1.57 ± 0.26. The K value in females showed significantly more rounder/plump (1.64 ± 0.24) compared to males (1.46 ± 0.22) in this domesticated population, and this pattern was also observed in a wild population (Ahmadi 2021). Moreover, several studies of Nile tilapia have shown that a K greater than 1.0 implies good fish health (Datta et al. 2013; Anani and Nunoo 2016). Normally, the K would remain the same when they got older if the proportion of BW and TL would not change (Firdaus et al. 2018). However, both high values of BD and K could be considered plump body shape indicators. Our analysis revealed consistently low correlations between K and TL across all sexes.

Moreover, the K showed the second-highest influence on BW, while the correlation between BD and BW was notably high. This highlights the importance of considering BD alongside BW to enhance consumer preferences (Sutthakiet et al. 2020). The complexity of the consumer market, the increase in the search for animals with more desirable external appearances, and the selection of appearance traits, particularly those associated with body shape, have gained prominence in production systems (Freitas et al. 2023). Furthermore, BD emerges as the second most crucial trait for selection criteria or inclusion in the selection index for snakeskin gourami genetic improvement programs.

This study emphasizes the need for a comprehensive approach to selective breeding programs for snakeskin gourami. Considering traits like BW, TL, BD, and K is crucial for genetic improvement. Categorizing the population into market sizes provides insights for strategic breeding aligned with market demands. The observed sexual dimorphism, where females exhibit larger sizes, is economically significant (Boonanuntanasarn et al. 2020). The study stresses a holistic approach, acknowledging the influence of unanalyzed factors like sex and cage conditions. Recommendations include expanding trait analysis to dimensions like body thickness and volume, drawing from studies in other fish species (Trọng et al. 2013; Reis Neto et al. 2014). The study suggests improving cultural conditions to foster size consistency by addressing size variation.

This study investigated the phenotypic variation and relationship between BW and key traits in domesticated snakeskin gourami at the 9-month harvest, highlighting significant correlations between BW and TL, BD, and K. The sexual dimorphism in females showed higher variation and a stronger correlation between traits of BD, TL, and K. This research informs the strategic formulation of breeding programs, considering intricate relationships among traits, market demands, and environmental factors. The comprehensive understanding established here guides decision-making for genetic enhancement and sustainable aquaculture practices for snakeskin gourami.

Conflicts of interest

The authors affirm that there are no conflicts of interest with any financial organization related to the material discussed in this manuscript.

Ethics approval

The Institutional Animal Care and Use Committee of Kasetsart University, with approval number ACKU65-FIS-001, provided ethical clearance for our research using these fish records.

Funding

This study was funded by Kasetsart University through the Graduate School Fellowship Program. The dataset for G₀ and G₁ was provided through the project (DPG5980003; Distinguished Research Professor TRF FY 2016) awarded by the Thailand Science Research and Innovation to Uthairat Na-Nakorn. The experiments and data collection for G₂ were supported by the Kasetsart University Research and Development Institute [KURDI; FF(KU) 3.65].

Author Contribution

The authors' contributions include Onprang Sutthakiet's work on data acquisition, analysis, interpretation, and drafting of the manuscript. Thanathip Suwansopee and Uthairat Na-Nakorn provided critical review and revision, and Skorn Koonawootrittriron contributed to the study design, data analysis and interpretation, critical review, and revision.

Acknowledgments

The authors wish to thank the Kamphaeng Sean Fisheries Station, Kasetsart University, Kamphaeng Sean Campus, Nakhon Pathom, Thailand, for providing access to facilities and for their excellent cooperation.

Data availability

The data that support this study will be shared upon reasonable request to the corresponding author.

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Phenotypic variation and relationships in body weight and composition traits of domesticated snakeskin gourami (Trichopodus pectoralis) at harvest

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Abstract

Figures

Introduction

Materials and methods

Experimental fish population

Production, nursing, and grow-out of fish

Data collection

Classification of snakeskin gourami sizing

Statistical analyses

Results

Characteristic of the snakeskin gourami population

Relationship between the measured harvest traits

Discussion

Conclusion

Declarations

Conflicts of interest

Funding

Author Contribution

Acknowledgments

Data availability

References

Additional Declarations

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