International Journal of Molecular Ecology and Conservation, 2025, Vol.15, No.3, 111-122 http://ecoevopublisher.com/index.php/ijmec 112 rate of juveniles, resulting in limited population replenishment (Yang et al., 2022). Some species of Spanish mackerel have been listed as near-threatened or vulnerable species (such as Australian spotted Spanish mackerel S. munroi, narrow-banded Spanish mackerel S. commerson, etc.), and need to be strengthened in protection (Jiang et al., 2020). Therefore, from the perspective of conservation and fishery management, it is urgent to study the evolutionary potential and mechanism of Spanish mackerel in adapting to environmental changes. Genome is the basis for understanding the adaptive evolution of species. At present, the research on the biology and population dynamics of Spanish mackerel is mostly focused on fishery assessment, nutritional quality and environmental pollution impact (Gao et al., 2024). Relatively speaking, the research on its phylogenetic relationship, genetic diversity and adaptive evolution mechanism is relatively weak. Genomic research can reveal the evolutionary history and adaptation mechanism of species from the whole genome, which is the key to analyzing how Spanish mackerel achieves local adaptation in a high gene flow environment. High-quality genome sequence and annotation can help determine the functional gene set and provide a platform for comparative genomics and population genomics analysis. At the same time, the acquisition of reference genomes is also crucial for the development of high-throughput molecular markers (such as SNP chips) for population genetic structure analysis and resource population division. This study will analyze the latest progress in the study of Spanish mackerel genome evolution, focusing on its adaptive evolution mechanism and the role of environmental selection in it. It will introduce the taxonomic status, biological characteristics and ecological adaptability of Spanish mackerel, provide a biological background for genome research, and outline the current research progress in Spanish mackerel genome sequencing and assembly, comparative genomics and functional genomics, and summarize the genome data and findings that have been obtained. Subsequently, the molecular mechanism of Spanish mackerel adaptive evolution is discussed in detail, focusing on how environmental selection drives Spanish mackerel genome evolution, and explaining the impact of environmental factors, the identification method of adaptive gene loci and the selection signals that have been discovered. Through specific cases, the adaptive evolution pattern of Spanish mackerel genome under the scenarios of temperature, salinity changes and migratory behavior is analyzed. This study not only provides a reference for the survival of the species itself, but also is a major help in maintaining the function of marine ecosystems. 2 Analysis of Biological Characteristics and Ccological Adaptability of Spanish mackerel 2.1 Taxonomic status and species distribution of Spanish mackerel The genus Scomberomorus belongs to the family Scomberidae of the order Scombriformes and is a medium-to-large ocean-dwelling migratory fish. The family Scomberomorus includes more than 50 species, including mackerel, tuna and Spanish mackerel, which are widely distributed in tropical, subtropical and temperate waters around the world. Among them, the genus Scomberomorus is an important branch of the subfamily Scomberinae (or Spanish mackerel) of the family Scomberidae (Alrashada, 2022; Widiasih et al., 2022). According to fish classification and molecular phylogenetic studies, Pacific Spanish mackerel (such as Japanese Spanish mackerel) and Atlantic Spanish mackerel (such as Spanish Spanish mackerel Scomberomorus maculatus) differ in morphology and genetics and can be regarded as different evolutionary lineages. The body of Spanish mackerel is streamlined, with two dorsal fins and a deeply forked caudal fin, which is suitable for fast swimming and chasing prey (Figure 1) (Jeena et al., 2022). Most Spanish mackerels are swimming animals in coastal waters, living in waters with higher water temperatures and abundant bait, and forming migratory paths along the coast and continental shelf waters. In terms of geographical distribution, Spanish mackerels are mainly distributed in the coastal waters of the Atlantic, Indian and Pacific Oceans. Among them, the narrow-banded Spanish mackerel (S. commerson) iswidely found in the tropical waters of the Indian Ocean and the western Pacific Ocean, from the east coast of Africa through the Red Sea, the Indian subcontinent to the South China Sea and the southern coast of Japan; the Japanese Spanish mackerel (S. niphonius) mainly lives in the temperate waters of the northwest Pacific Ocean, including the Yellow Sea, Bohai Sea and East China Sea of China, and the coast of Japan; while the Atlantic Spanish
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