Chapter 10 Secondary Productivity in Coastal Lagoons

Abstract

Secondary productivity is the net production of consumers above respiration and excretion. A major difference between secondary and primary productivity is that no single measurement can be used to characterize the secondary productivity of a community. We still know very little about the secondary productivity of coastal lagoons. With scarce available data, it seems that the zoobenthos are the most productive animals, specially the suspension feeders (up to more than 200 g AFDW m −2 year −1 for the whole macrobenthic assemblage but more commonly with values around 20). The zooplankton have a productivity as high as half that of the zoobenthos. The nekton has a productivity between about 10% of and similar to that of the zooplankton. Relatively much more is known of the secondary productivity of temperate lagoons than that of tropical lagoons; and much needs to be done to have a good set of cases for comparisons. In the case of leaky lagoons, with short turnover times, a detailed description of their hydrodynamics and that of the adjacent oceanic areas is a prerequisite to work on secondary productivity. This is specially important in the case of estimating secondary productivity of zooplankton. In the case of nekton, crustaceans, and mollusks, we are moving towards a situation with very few coastal lagoons left for analysis of natural secondary production. Most cases will be in the realm of fishery and aquaculture sciences.