Mesozooplankton (mesoZP) per capita mass, elemental composition and stable N isotopes during the mesocosm experiment in the Canary Islands in autumn 2019. Depth-integrated (0-2.5m) water samples were taken over the course of 33 days. Metazoan zooplankton were split into three size fractions (55-200, 200-500 and >500 µm), picked into tin cups in groups and C, N and δ15N measured in an element analyser coupled to a mass spectrometer. Particulate organic matter (>0.7µm) was also measured for a comparison of C/N between the bottom of the food web and mesoZP grazers. The upwelling treatment started on day 6. Methodological details in Goldenberg et al. (doi:10.3389/fmars.2022.1015188) and Goldenberg et al. (under review).