<b>Thermal adaptation of energy allocation and reproduction during aestivation in northern and southern populations of western sand lance (</b><b><i>Ammodytes japonicus</i></b><b>)</b>

This dataset contains the raw and processed data used in the study “Thermal adaptation of energy allocation and reproduction during aestivation in northern and southern populations of the western sand lance (<i>Ammodytes japonicus</i>)”. It includes measurements of fish size, somatic weight, lipid and protein contents, total energy estivates, fecundity and egg size for all experimental treatments. These data enable full replication of the analyses and support the study’s findings on population differences in energy used and reproductive investment under contrasting thermal conditions.