DRAKES ESTERO: Contractors working for the Point Reyes National Seashore began the removal of oyster racks in Drakes Estero last week. Old racks are being removed first, seashore scientist Ben Becker said; then excavators with special buckets, which have holes in them to drain sediment back into the bay, will skim debris off the bottom. Divers will find any remaining debris. Recovered oyster shells will be distributed to two organizations for reuse, and treated wood from oyster racks will be sent to the dump. The estero is closed on weekdays and open on weekends to the public while the project is underway, likely through winter.