 Both Neotrypaea californiensis and the mud shrimp Upogebia pugettensis live in mudflats and sandy substrates in the intertidal zone of estuaries in western North America. N. californiensis is found from Mutiny Bay, Alaska to Punta Abreojos, Mulegé, Baja California Sur, Mexico. Its habitat is also used for the aquaculture of the Pacific oyster, Crassostrea gigas. Since the bioturbation carried out by N. californiensis and U. pugettensis reduces the productivity of the oyster beds, they are considered pests. Their effects may, however, have knock-on effects across the entire ecosystem, and may buffer it from the hazards of nutrient enrichment and increase primary and secondary productivity by increasing the amount of dissolved inorganic nitrogen.
