Abundance of invertebrates (approximately < 1 cm in size) found in sediment samples collected throughout the region. Samples are collected as part of The City’s Ocean Monitoring Program, which monitors the effects of treated wastewater effluent on the local marine environment. The OMP extends 340 square miles total from northern San Diego to northern Baja California, Mexico, and encompasses the shoreline seaward approximately 10 miles, to depths of over 500 meters.