Fish Immunology Adaptations: From Evolutionary Origins to Global Climate Resilience

The ongoing global climate crisis is characterized by rising mean water temperatures, thermal stress, ocean acidification, and fluctuating dissolved oxygen levels. These factors pose an unprecedented challenge to the homeostasis of ectothermic vertebrates. In this context, the fish immune system emerges as a critical biosensor, and its inherent plasticity is essential for species survival in rapidly changing ecosystems. The investigation of fish immunological dynamics is imperative for scientific and socioeconomic reasons and ecosystem services performed by these organisms. The phenomenon of global warming has been demonstrated to facilitate the expansion of the geographic range of bacterial and viral etiological agents. This necessitates the mapping of the responses of innate and adaptive defenses to novel antigenic loads. Furthermore, ascertaining the influence of abiotic parameters on cellular signaling and the kinetics of the immune response is imperative, as these parameters are frequently compromised when thermal optima are exceeded. The immune system of fish is characterized by its dynamic nature, manifesting adaptive responses over a range of timescales. In the short term, we observe phenotypic plasticity and epigenetic regulation, which enable individuals to modular immune gene expression in response to environmental stressors. From an evolutionary perspective, climate change exerts a significant degree of selective pressure, thereby driving rapid genetic divergence. Recent studies suggest that evolution favors more resilient polymorphic variants of the major histocompatibility complex (MHC) and toll-like receptors (TLRs), which maintain binding efficiency under thermal instability. It is imperative to comprehend the mechanisms of "immuno-eclipse" and resilience to ensure the conservation of biodiversity and the assurance of biosecurity in the global aquaculture sector.We welcome the submission of Original Research, Review, Mini Review, and Perspective articles on themes including, but not limited to:• Immune system of fish;• Morpho-functional adaptations of aquatic organisms in response to environmental stress;• Evolution of innate and adaptive responses in relation to ecosystem changes;• Biodiversity conservation and environmental sustainability;• Comparative and evolutionary immunology across species, phylogenies, and biogeographic contexts;• Multi-stressor frameworks (warming × hypoxia × acidification × pollutants × pathogens) and non-additive immune outcomes;• Biosecurity, disease surveillance, and immune biomarkers as early-warning indicators for aquaculture and fisheries management.• Epigenetic regulation of immune responses and potential transgenerational effects under environmental stress;• Population genomics and local adaptation of immune loci (e.g., MHC, TLRs, cytokine genes) under climate-related selective pressures;• Mucosal immunity and barrier defenses (skin, gill, gut) under climate-relevant stressors (temperature, acidification, hypoxia). Topic editors: Alessio Alesci, Roberto Ferreira Artoni Source: https://www.frontiersin.org/research-topics/78625/fish-immunology-adaptations-from-evolutionary-origins-to-global-climate-resilience