Integrative Analysis of Metabolic, Physiological, and Morphometric Traits in Wild and Cultured Cyprinus carpio: Insights into Adaptive Divergence and Energy Allocation

Abstract

The common carp, Cyprinus carpio, represents one of the most ecologically and economically significant freshwater fish species worldwide, exhibiting remarkable phenotypic plasticity that enables it to thrive in diverse environmental conditions. Understanding the interplay between metabolic, physiological, and morphometric traits in both wild and cultured populations of C. carpio is critical for elucidating mechanisms of adaptive divergence, energy allocation, and ecological resilience. In this study, an integrative approach was employed, encompassing a detailed examination of metabolic rates—including routine metabolic rate (RMR), maximum metabolic rate (MMR), aerobic scope, and oxygen consumption efficiency—to quantify energy expenditure, energy budgeting, and metabolic flexibility in varying environmental contexts.

Physiological traits were systematically assessed, including hematological indices such as hemoglobin concentration, hematocrit levels, red and white blood cell counts, plasma protein profiles, enzymatic activity related to oxidative stress (superoxide dismutase, catalase, glutathione peroxidase), and stress biomarkers including cortisol and lactate levels. These measures provided insight into the health status, stress tolerance, and adaptive capacity of populations subjected to natural vs. aquaculture conditions. Morphometric analyses included standard length, body depth, fin morphometrics, body mass, and condition factor calculations, combined with geometric morphometric approaches to capture shape variation, allometric growth patterns, and structural adaptations related to locomotion, foraging efficiency, and predator avoidance. Comparative analysis revealed that cultured carp exhibited elevated growth rates, increased somatic mass, and energy allocation patterns favoring anabolic processes, whereas wild populations demonstrated traits consistent with enhanced environmental responsiveness, efficient energy budgeting under fluctuating resource availability, and structural adaptations promoting survival in heterogeneous habitats. Multivariate analyses, including principal component analysis (PCA) and canonical correlation analysis (CCA), highlighted strong interdependencies among metabolic, physiological, and morphometric traits, demonstrating how energy allocation strategies are modulated in response to both intrinsic genetic factors and extrinsic environmental pressures. Notably, correlations between aerobic capacity and morphometric shape indices suggest adaptive trade-offs between growth optimization in cultured populations and resilience to environmental stressors in wild populations. These findings underscore the importance of integrative, multi-trait assessments for understanding the evolutionary ecology of C. carpio, offering practical insights for selective breeding programs aimed at optimizing growth, health, and resilience in aquaculture while preserving genetic and phenotypic diversity in wild populations. This comprehensive study establishes a framework for linking energy metabolism, physiological function, and morphological variation to adaptive divergence, providing a foundation for future research on phenotypic plasticity, resource allocation strategies, and ecological adaptation in freshwater teleosts. Ultimately, the integration of metabolic, physiological, and morphometric data allows for a nuanced understanding of how wild and cultured carp populations balance energy investment between growth, maintenance, and survival in response to environmental and anthropogenic pressures, offering a roadmap for sustainable aquaculture development and biodiversity conservation.