GIS Project to Categorize and Map Smalltooth Sawfish (Pristis pectinata) Shoreline and Nearshore Habitat Features in Southwest Florida

Abstract

This project was conducted in cooperation with NOAA Fisheries to support the management of smalltooth sawfish (Pristis pectinata) in Charlotte Harbor, Florida. Smalltooth sawfish have experienced a serious decline in their range due to commercial and recreational fishing, entanglement, illegal trade, and coastal development. In the United States, they once ranged from Texas to North Carolina, but are now only found in parts of southern Florida. NOAA Fisheries manages smalltooth sawfish under the purview of the Endangered Species Act and has designated Charlotte Harbor and the Ten Thousand Islands/Everglades as critical habitat units for the U.S. distinct population of this species. These areas were chosen as they have an abundance of mangroves in shallow, euryhaline water which is prime nursery habitat for sawfish. This project focuses on the Charlotte Harbor unit of critical habitat and utilizes ArcGIS to categorize the shoreline with emphasis on classifying and analyzing mangroves to identify priority sawfish habitat. A supervised classification using the maximum likelihood classification method is used to categorize the shoreline into three classes: mangrove, other vegetation, and non-vegetation. Classified mangroves are then analyzed to identify contiguous mangrove patches, mangrove distance to shoreline, and mangrove neighborhood density. The products from this project will be combined with other datasets to develop a sawfish distribution model. Such a model could be useful in predicting sawfish abundance across seascapes to promote better management of this endangered species.