Title: Mapping the Effects of Blast and Chemical Fishing in the Sabalana Archipelago, South Sulawesi, Indonesia, 1991-2006
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Author: Hlavacs, Lauri A.
Degree: Master of Arts , Southeast Asian Studies , 2008.
Advisors: Gene Ammarell PhD (Committee Chair)
The overall purpose of this project was to demonstrate the usefulness and cost effectiveness of Landsat imagery in mapping reef damage resulting from the use of two destructive fishing practices, blast and chemical fishing. As a side benefit, the protocol can be used in educational settings where scientists as well as high school and university students can map these unsustainable activities over large areas.
The living coral reefs of eastern Indonesia are the most diverse in the world, and they are also among the most threatened by human activity. The long illegal destructive fishing practices of chemical and blast fishing have been so widely used that many of the reefs have been damaged to the point of habitat-wide collapse. This project focuses on the formerly highly productive reefs surrounding a small chain of islands in the Sabalana Archipelago, a group of islands located roughly half the distance between the main Indonesian islands of Sulawesi and Sumbawa.
Habitat-scale change was mapped in four change images between 1991 and 2006 using the increase in relative brightness as the habitat shifted from coral-dominated to algae-dominated and then to dead coral rubble. The output images illustrated how the damage spread throughout the area as fishermen using destructive fishing practices progressively exhausted the resources. The destructive fishing effects were differentiated from larger bleaching events in the characteristic that they resulted in a patchy increase in brightness over the entire reef. Using this image differencing method, Landsat TM and ETM+ scanners were shown to be useful and extremely cost effective in mapping the effects of blast and chemical fishing in the study site.
destructive fishing; blast fishing; chemical fishing; Landsat; Sabalana Archipelago; South Sulawesi; Indonesia; coral reef loss; coral reef mapping; change detection; image differencing.
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