DIFFERENT PERSONALITY TRAITS AND SPECTRAL PREFERENCES OF SCOPHTHALMUS MAXIMUS: AN ANALYSIS BASED ON SPECTRAL SELECTION BEHAVIOR ACROSS DIFFERENT DEVELOPMENTAL MONTHS

As one of the key environmental factors in aquatic ecosystems, light exerts a profound regulatory effect on the physiological status, behavioral patterns, and even core survival adaptability of fish. Fish exhibit selective preferences for specific spectral environments, which are closely associated with habitat characteristics, foraging strategies, and ecological adaptability. Although previous studies have confirmed that fish display selective preferences for light environments, the role of personality differences in their light environment selection remains unclear. Taking juvenile turbot (Scophthalmus maximus) as the research object, this study established red, orange, green, blue, and white spectral zones. By analyzing the relationships between behavioral phenotypes and spectral preferences of juvenile turbot at 2, 3, and 6 months of age, we aimed to address two core questions: (1) whether individuals with different personalities exhibit differentiation in spectral selection; and (2) how such differentiation dynamically changes with age (in months). The results showed that juvenile fish at all age stages exhibited a significant preference for blue-green light (450–550 nm), while their selection ratio for red light (>600 nm) remained consistently below 10%. This conservatism in preference aligns with the propagation advantage of short-wavelength light in water and the visual physiological characteristics of teleost fish. Nevertheless, personality type significantly influenced the pattern of spectral selection: Brave individuals displayed a highly stable preference for blue light (58.33% at 2 months to 53.33% at 6 months, with <5% fluctuation), and their swimming speed was significantly faster than that of shy individuals (P<0.05). In contrast, shy individuals showed greater behavioral plasticity, characterized by intermittent high preference for green light and exploratory behavior under red light. With development, the stability of light preference behavior in brave individuals increased, which may be attributed to their stronger sensitivity to environmental spectral signals, whereas shy individuals maintained a fluctuating selection strategy, reflecting a risk-averse survival strategy. In summary, juvenile turbot exhibit a significant preference for blue light at all age stages (in months), while their selection ratio for red light remains consistently the lowest. This trait aligns with the evolutionary adaptive characteristic of the teleost visual system, which exhibits high sensitivity to short-wavelength light. Meanwhile, personality type exerts a significant regulatory effect on their spectral selection behavior: Specifically, brave individuals not only displayed a significantly higher selection ratio for blue light but also maintained high stability throughout the entire developmental cycle. This pattern may be closely associated with the developmental characteristics and expression patterns of opsins in this personality type of juvenile fish. In contrast, shy individuals showed significantly higher behavioral volatility, including stage-specific high preference for green light preference, suggesting a risk avoidance strategy through behavioral adjustments. These findings not only confirm the adaptive evolution of juvenile turbot to the spectral conditions of coastal benthic habitats but also provide new empirical evidence for deciphering the physiological regulatory mechanisms underlying the interaction between fish behavioral plasticity and environmental factors.