Hydrocasts were conducted during which data on depth, temperature, salinity, fluorescence, and dissolved oxygen were recorded using a Seabird 911 Plus CTD equipped with a WET Labs ECO-AFL/FL sensor to estimate chlorophyll and an SB43 to measure oxygen. These measurements were carried out in a coastal area of the tropical Mexican Pacific during the "MareaR" I, III, V, IX, X, and XI campaigns in April of 2009, 2011, 2013, 2017, 2018, and 2019, covering the regions from Cabo Corrientes (northern limit) to Acapulco (southern limit), including Manzanillo, Maruata, and Lázaro Cárdenas. The objective of these cruises was to understand the spatial and interannual variability of the oxigen mínimum zone.