# Growth Pattern and Condition in the Mudskipper Scartelaos histophorus in the Mekong Delta

## TL;DR

This study analyzed growth patterns and body condition of mudskippers in the Mekong Delta, finding differences based on sex and season.

## Contribution

The study provides hypothesis-driven baselines for monitoring semi-terrestrial gobies by examining growth and condition factors across sex and season.

## Key findings

- Mudskippers showed negative allometric growth with a consistent exponent (b = 2.46 ± 0.02).
- Females had higher growth exponents and condition factors than males.
- Growth exponents and condition factors varied seasonally, with higher values in the dry season.

## Abstract

Studies of the length–weight relationship (LWR) and condition factor (CF) in fish are abundant but often descriptive; yet, most studies overlook how intrinsic and extrinsic drivers structure these metrics. Here, this study tested whether the growth exponent (b) varies across sex, season, and ecological region, and whether CF is elevated in females and before spawning. Over the course of a complete annual cycle, a total of 1436 individuals were collected from four mudflat sites, measured for total length (TL) and weight (W), and analyzed using log10‐linear regressions of LWR and CF, along with appropriate parametric or non‐parametric tests under false discovery rate control. The TL strongly predicted W (r
2 = 0.87) with b = 2.46 ± 0.02 SE, (< 3; p < 0.001), indicating negative allometry. Females showed a larger size and higher b value (2.52) than males (2.41). The dry season yielded a higher b value than the wet season, and southern sites showed a non‐significant trend towards a higher b value than northern sites. Mean CF was 1.01 ± 0.01 SE, elevated in females (1.09 vs. 0.98) and in the dry season (1.04 vs. 0.99), while monthly fluctuations (0.89–1.08) tracked feeding and reproduction but showed no regional differences. Overall,
S. histophorus
exhibits consistently negative allometric growth, with systematic variation in b and CF across sex and season. These findings provide hypothesis‐driven baselines for monitoring semi‐terrestrial gobies and highlight the importance of considering life‐history and hydrological context when applying LWR/CF in ecological and evolutionary research and management.

Analysis of 1436 mudskippers (
Scartelaos histophorus
) from the Mekong Delta revealed consistently negative allometric growth. Growth exponents and condition factors were higher in females and during the dry season, emphasizing the roles of life‐history and hydrological drivers in estuarine adaptation.