A geographic information system for fisheries management in American Samoa

This study illustrates a geographic information system developed to effectively analyze and visualize temporal and spatial patterns of the longline fishery in the American Samoa’s Exclusive Economic Zone. The pelagic and tuna fishery in American Samoa has historically been an important component of the traditional domestic fisheries and nation’s economy. This paper presents an innovative way to utilize the geographic information associated with fisheries data. It also introduces the associated custom software component developed using Visual Basic for Applications and ArcObjects within the Environmental System Research Institute ARCGIS 8.3 software. The application provides a user-friendly analysis interface allowing for easy output production. It is extremely flexible and can be used for studies at multiple scales, locations and extents. Output spatial data are produced in the most widely used file formats. This allows easy data sharing and provides inputs for further analysis, for example in conjunction with environmental data like satellite derived sea surface temperature and ocean color. The main functions of the fishery GIS are catch and effort estimation and their variation in space and time, fishing vessel utilization, data quality control, and deriving information on the location of important economic and threatened species. Fishing pressure maps can be now developed based on spatial density of deployed hooks. Total catch and catch for selected species are analyzed and mapped using analogue techniques. Catch per unit of effort grids are produced as a ratio between hook density and catch density surfaces. Areas with high fishing pressure and changes in fishing pressure and catches within several time frames are spatially and temporally identified and presented as animations. The system can be quickly adapted to any fishery database where date, location and catch information are stored.