Long-term trends in abundance and growth indices of seagrasses were compared between 1969 and 1994 at 2 locations in Barbados and at Carriacou in the Grenadine island chain. Abundance (as frequency of occurrence, shoot density, leaf biomass, areal coverage) and growth (as maximum leaf length, leaf width, leaf productivity, leaf plastochrone interval, leaf growth rate) of Thalassia testudinum were substantially lower in 1994 than in 1969 at the 2 Barbados locations. Abundance of Syringodium filiforme (as frequency of occurrence, leaf biomass) was higher in 1994 than in 1969 at both locations. Differences in abundance and growth of Thalassia, and in abundance of Syringodium, were much less marked at Carriacou than at Barbados between 1969 and 1994. A comparison of seagrass areal coverage between 1969, 1983 and 1994 suggest that the impact of Hurricane Allen in 1980 may have been primarily responsible for the decrease in Thalassia abundance at the 2 Barbados locations between 1969 and 1994. The increase in Syringodium abundance may best be explained as a response to the decreased Thalassia abundance, and the high Syringodium abundance may partly explain the depressed growth indices of Thalassia now evident. Sediment accretionary trends and nutrient enrichment of the coastal zone at 1 of the 2 Barbados locations may also be contributing to the abundance and growth changes observed.

A combination of SPOT data and high-resolution aerial photography was used to map the benthic habitats of the Bermuda platform. The purpose of the study was to generate a base map for future monitoring, and to test the use of the habitat map, along with a multi-level GIS, for ecological applications. Bermuda possesses the northernmost coral reefs and mangroves in the Atlantic Ocean. Because of its high population density, both the terrestrial and marine environments are under intense human pressure, highlighting the need for assessment and monitoring of key benthic habitats.

The study combined a number of image processing techniques in order to distinguish the greatest number of benthic habitat classes possible, including several coral reef classes. Following an extensive accuracy assessment, the map was used as a basis for resource assessment and for calculating the feeding area available for the green turtle (Chelonia mydas). Green turtle densities per habitat and overall carrying capacity were also estimated. The mapping was achieved with low-cost software and existing satellite imagery, providing a viable alternative for those looking for cost-effective coral reef mapping options.