Análisis del uso del suelo por acuicultura en el delta del Canal del Dique entre 1986 y 2003 (Caribe colombiano)

Abstract

In the southern region of Cartagena de Indias city (Colombia’s Caribbean coast), is the canal of the Dique, canalized natural arm of the Magdalena river that forms a three mouths delta. This delta is colonized by mangroves dominated mainly by Rhizophora mangle, Avicennia germinans, Laguncularia racemosa and Pelliciera rhizophorae. It was traditionally exploited for along time. Mangroves were degraded to be used for wood production for construction and for vegetal coal. Additionally, during the eighties an agro-industrial activity with the aquaculture infrastructure installation (ponds), predominated for breeding Penaeus vannamei shrimp and P. stylirostris for exportation. The development of the aquaculture industry induceda strong pressure on the sector of the canal of the Dique, transforming radically the delta’s landscape. The authors intend to show the evolution of the land use in the delta between 1986 and 2003, using a satellite track down with the Landsat TM, ETM, Spot HRV and HRG images (18 images in total). The interpretation of these images allowed mapping the dynamics of the surfaces that were converted into structures for aquaculture. The alteration of the delta’s hydrology (deviation of preexisting channels, opening of new channels, coastal lagoon drainage) was mapped as well. The aquaculture industry crisis, as a result of the appearance of the syndrome of Taura virus in the shrimp farms, began during 1992 and persisted up to1997. The results of this study show that the common belief of mangrove degradation due to the development of the aquaculture industry is not real. In the study area, mainly the surfaces of lagoons and salty swamps were used to establish aquaculture infrastructure. Spatial teledetection was a useful tool to carry out a satellite track down of the aquaculture development in the delta of a tropical zone: the canal of the Dique. The Landsat (TM andETM) and Spot (HRV and HRG) images chronicle used, allowed the accurate mapping (yearly or every two years) of the dynamics of the mangrove surface as well as the extension of the aqua culture ponds. Given their repetitive, synoptic and multispectral characters, satellite images constitute a fundamental instrument for coastal monitoring.