During the past 15 years, Ecuador has become the Western Hemisphere's leading producer and exporter of shrimp. Growth has come about largely through mariculture development. About 8,000 MT of shrimp have been captured off the Ecuadorian coast each year since the late 1970s. Meanwhile, pond output has increased considerably, from less than 5,000 MT to 100,000 MT in the 12- year period from 1979-91. Mariculture has expanded largely at the expense of renewable natural resources. Mangrove swamps, characterized by very high biological productivity and, therefore, a critical element of coastal ecosystems, have been displaced. in addition, shrimp post larvae collection has at times been excessive, and wastewater emissions from some enterprises have harmed the environment. Mariculture also suffers from water pollution from agricultural, urban, and industrial sources. This paper first describes the extent and consequences of coastal ecosystem disturbance; then presents a causal analysis of environmental problems. Policies contributing to depletive management of wetlands and related resources are similar to policies stimulating tropical deforestation. The tenurial regime rewards those who convert coastal ecosystems into shrimp ponds, just as frontier property arrangements encourage agricultural colonists to convert natural ecosystems into farmland. in addition, mariculture's geographic expansion, like agriculture's, has been accelerated by inadequate spending on education, research, and extension. If this policy regime remains unchanged, continued deterioration of Ecuador's coastal ecosystems is inevitable. (Author abstract)