Three performance indicators were selected. The first performance indicator monitors all vessels transiting the ATBA, as a percentage of those vessels transiting within the sanctuary. In the same period of 1999, there were 511 transits in the ATBA, of which 18 were tank vessels. Representing total vessel transits in the ATBA, as a percentage of those in the sanctuary, the values dropped from 27.1 percent to 20.5 percent within the same period. For tank vessels, the values dropped from 22.6 percent to 4.6 percent in the same period.
Maritime commerce is an important use of the ocean.
Ensuring that commercial shipping is compatible with the protection of marine resources represents one of the sanctuary's, and the maritime industry's, greatest challenges. Further evaluation of tank vessels within the ATBA illustrates the relative decreases in the different classes of tank vessels in the Olympic Coast National Marine Sanctuary ATBA since it went into effect in 1995. The most dramatic decreases are in the coastal and ocean going tanker and barge categories. Therefore, future improvements in the effectiveness of the ATBA, or at the very least the maintenance of the current effectiveness, will depend upon the continued involvement of vessel traffic managers, industry groups, and the mariners themselves. In addition to monitoring the effectiveness of the sanctuary ATBA, other uses of these data and methodologies can be applied to other vessel traffic systems and waterways.