Fish Adaptation in a Changing Climate: A Mapping Analysis.

Climate-driven warming, oxygen loss, acidification, salinity change, and extreme events increasingly challenge fish performance and persistence. This review mapped the global development of fish-adaptation research from 1975 to 2025 using 83,614 articles and 4,272,627 cited references. Publication, collaboration, keyword, citation-burst, and reference co-citation analyses were integrated with critical biological synthesis. Annual output increased at an estimated 9.02% per year from 1975 to 2024, although proposed boundaries at 2010 and 2019 were not statistically significant publication-growth breakpoints and were retained only as interpretive periods. Research evolved cumulatively from salmonid and organismal physiology toward climate-oriented, molecular, disease, genomic, and field-monitoring approaches. Global output and network connectivity remained concentrated among a limited number of countries and institutions, while established model species continued to dominate major research themes. Citation bursts also showed strong methodological visibility, which should not be equated with biological importance. Emerging priorities include multi-stressor experiments, sensitive life stages, tropical and other underrepresented systems, long-term monitoring, environmental DNA, and stronger linkage of molecular responses to demographic outcomes. The evidence is limited by single-database coverage, English-language and document-type restrictions, broad search terminology, metadata inconsistencies, citation bias, and parameter-dependent network construction. Equitable funding, capacity building, and research leadership in climate-vulnerable regions are needed to improve the biological and management relevance of future fish-adaptation research.