The objective of this project was to identify priority marine conservation areas in the Guayaquil Ecoregion. This was a binational project (Ecuador-Peru) that took place with funding from The Nature Conservancy (TNC) in 2004, and constituted the first effort to evaluate marine ecoregions in South America.

The Guayaquil Marine Ecoregion extends from 0° to 6° 15´ latitude South and out to the edge of the continental shelf (200m depth). It covers a total area of 3,236,617 hectares. This Ecoregion is characterized by the mix of different tropical and subtropical water masses, forming an extensive transition zone between the Panama and Peru provinces. It also contains a wide variety of coastal marine ecosystems, ranging between coral reefs, rocky bottoms, mangrove forests, sandy beaches, lime cliffs, and rocky coasts and inlets.

The littoral zone in this Ecoregion is densely populated, and is adversely affected by human activities. Among the principal threats are urban and industrial contamination, effects of tourism, and extractive activities such as fishing and the cutting of mangroves.

In order to determine the patterns of marine diversity and to identify conservation targets in the Gauyaquil Ecoregion, the area was stratified and classified into various Marine Ecological Units (MEUs). Each one of these units encompasses a variety of coastal marine systems with similar patterns of temperature, depth, continental influences, and species distributions. The MEUs were then subdivided into intertidal and subtidal systems. The conservation targets also included critical areas for reproduction, nesting, and feeding of sea turtles and birds, as well as an extensive community of green algae in the subtropical MEU. Although the total number of marine species in the Ecoregion is still unknown, 83 species of special importance were chosen as conservation targets.

We performed a geographical conservation aptitude analysis based on the geographic distribution of the conservation targets and their threats. This analysis aided in identifying conservation sites far from the zones of high impact from human activities. Based on the abundances of conservation targets within the Ecoregion, a conservation goal was specified for each one, as well as identifying priority conservation areas using the SITES program. This program chooses a portfolio of sites that optimize low costs, high goal achievement, and proper grouping of analytical units.

The resulting portfolio has 53 blocks distributed among all of the MEUs, achieves the majority of conservation goals, and is concentrated in areas of relatively low cost. The majority of the conservation objectives are represented in the 18 blocks of very high and high priority.

This study constitutes a valuable addition to the general knowledge of the biodiversity of coastal marine systems, the spatial distribution of their threats, and the gaps in information and conservation that exist within the Ecoregion.