From samples taken during the oceanographic cruises TALUD IV–X in the southern and central Gulf of California, Mexico, 291 specimens of Lucinoma heroica were obtained in a depth interval of 731 to 991 m. The species occurred under conditions of severe (<0.1 ml l−1O2) and moderate hypoxia (0.1–0.5 ml l−1O2). The correlation between height and length of the shell showed isometric growth with a trimodal size distribution, showing an average interval of 3.75 mm to 47.40 mm in height and 4.96 mm to 54.00 mm in length. Small individuals (≤20 mm) were distributed in a moderate hypoxic environment, while the larger (>35 mm) tolerated an almost anoxic habitat. Medium-sized specimens (21–35 mm) were found in concentration close to 0.2 ml l−1O2. Average density was 1.532 ind l−1 in infauna samples (dredge and core) and 0.002 ind m−2 in epifauna samples (benthic sledge).
