Mysids and environmental monitoring: a case for their use in estuaries

Abstract

Mysids (Crustacea : Mysidacea) are ubiquitous members of the permanent, endemic hyperbenthic fauna of estuarine and other coastal ecosystems. They often occur in high numbers and their ecological importance, particularly their role in food chains as a link between the benthic and pelagic systems, is becoming increasingly apparent. In general, mysids are omnivores, feeding on detritus, zooplankton and phytoplankton, and they contribute up to 40% of the standing stock of omnivores in some systems. In estuaries, specific mysid faunas often occur in discrete zones, usually as a result of different salinity tolerances, although responses to turbidity and water flow also determine mysid distributions. Many mysids are particularly sensitive to chemical contaminants as illustrated by their relatively low 96-h LC₅₀ values. Due to this sensitivity, the United States Environmental Protection Agency promotes the use of Americamysis ( Mysidopsis) bahia for laboratory toxicity testing; however, there is growing interest in the use of local, endemic species rather than the standard American mysid. At Plymouth, novel and sensitive techniques are being developed for assessing sublethal responses to toxicants by use of the northern European estuarine mysid Neomysis integer. This paper summarizes the ecological role of mysids in estuaries and describes their potential for use for estuarine environmental monitoring.