Sorbent boom has been placed on three nearby salmon habitat streams and in a U-shape around a fishing boat that sank 40 miles northwest of Sitka.
State conversation authorities say a remotely operated vehicle has found the seine net from the Evening Star, but the boat in Slocum Arm, in water as deep as 400 feet, couldn't be seen by the camera.
The ship had been carrying about 1,000 gallons of diesel fuel and other oils. It sank Aug. 2 and officials last week observed a rainbow sheen a mile long and 25 yards wide.
The sheen shrank over the weekend to 350 feet long.
The net will be removed to prevent dive gear or marine mammals from getting tangled. Crews will assess whether the ship can be salvaged.