Pacific oysters have a pelagic veliger larval stage which lasts from 14–18 days. In the hatcheries, they are kept at temperatures of 25-28 °C with an optimum salinity between 20 and 25%. Early-stage veligers (<120 nm shell length) are fed daily with flagellated algal species ("Isochrysis galbana" or "Pavlova lutherii") along with diatom species (either "Chaetoceros calcitrans" or "Thalassiosira pseudonana"). The larvae are close to a settlement stage when dark eye spots and a foot develop. During this time, settlement materials (cultch), such as roughed PVC sheets, fluted PVC pipes, or shells, are placed into the tanks to encourage the larvae to attach and settle. However, particularly on the US West Coast, mature larvae are commonly packed and shipped to oyster farms, where the farmers set the oysters themselves.