The use of Geographic Information Systems to assess the compliance of ballast water management for commercial ships operating in California

The California State Lands Commission´s Marine Invasive Species Program (MISP) administers the state´s program to prevent nonindigenous species (NIS) introductions to California waters through the discharge of ballast water from commercial vessels. Ballast water discharge from commercial shipping is a primary source of the introduction of NIS into California waters. Vessels arriving to California are required to submit ballast water reporting forms upon departure from each port or place of call. These forms detail ballast water management activities for more than 10,000 vessel arrivals each year, forming a robust dataset through which compliance and management patterns can be examined, including geographic and temporal analysis of source and exchange patterns of ballast water that is discharged within the state. Compliance with the requirement to submit the ballast water reporting forms have consistently exceeded 95% (from 2004-2013), due in part to an active inspection and outreach program. The use of Geographic Information Systems (GIS) allows the MISP to assess compliance on several levels, including the source and management (ballast water exchange) locations of all reported ballast water discharges into California waters. GIS analyses can also illustrate broad patterns and processes, such as densities of noncompliant ballast water discharges by location, which offer greater insight into potential NIS hotspots and areas of increased risk. These data shed light on the quantities and geographies of managed ballast water, where such water has been exchanged, and where it has been discharged. Such analyses provide valuable information that can inform the development and revision of effective ballast water management regulations, as well as inform both retrospective and predictive studies of NIS invasion patterns.