Shell Oil says it has begun exploratory drilling in the Beaufort Sea off Alaska’s north coast as it continues to drill in the neighboring Chukchi Sea.

Shell Alaska spokesman Curtis Smith says Beaufort drilling started Wednesday after the end of an Alaska Native whale hunt.

Smith says the company hopes to drill until the seasonal Oct. 31 deadline.

Shell announced last month it would limit drilling this year to non-petroleum zones.

The company can’t drill into those zones until its spill response barge is in place, and Smith says that won’t happen this year.

A containment dome on the barge was damaged in tests last month.

Royal Dutch Shell PLC has spent $4.5 billion on Arctic offshore drilling, moving ahead in spurts to overcome court challenges and scrutiny.