Dataset: CTD profiles collected from the San Pedro Ocean Time-series (SPOT) station in the San Pedro Basin, Southern California Bight, aboard R/V Yellowfin on February 19, 2025

CTD profiles were collected using a Sea-Bird CTD system deployed from the research vessel during the SPOT cruise. The dataset includes two CTD casts conducted on February 19, 2025, which are distinguished using a Cast_ID column. The instrument was stabilized near the surface (0–5 m) prior to profiling and then lowered through the water column at a controlled rate of approximately 10–40 m min⁻¹. Sensor data were recorded continuously during the downcast, and discrete water samples were collected during the upcast using Niskin bottles mounted on the rosette.

The CTD system consisted of a Sea-Bird Electronics SBE 9plus equipped with sensors for pressure, temperature (SBE 3), conductivity (SBE 4C), and dissolved oxygen (SBE 43), as well as auxiliary sensors including photosynthetically active radiation (PAR), chlorophyll fluorescence (WET Labs ECO-AFL), turbidity, and beam transmission (C-Star transmissometer). Sensors were regularly calibrated by the manufacturer to ensure data accuracy.