Habitat Productivity: Salt Marshes

Recent investigations show that direct utilization of marsh surfaces can influence productivity of fisheries. In the past it was thought that fishery species used marsh creeks, and not marsh surfaces as nurseries. Early indications of a more direct relationship showed that marsh infauna were impacted by aquatic predators and that offshore yields of some species, like brown shrimp, could be related to the amount of inshore marsh area. It was not until introduction of drop trap and flume net sampling methods that measurments of marsh consumers became available. These studies revealed that large numbers of estuarine nekton (especially the juveniles of fishery species) invade tidal marsh surfaces. In Galveston Bay, densities of predatory consumers were significantly greater in marshes that in nonvegetated subtidal habitat. Moreover, salt marsh faunal densities were shown to be equivalent to consumer densities found in seagrasses.