Biological processes in seagrass beds of coastal lagoons to maintain estuary-dependent marine fisheries

Following the planned FAO Ecosystem Restoration Programme for estuarine habitats to support estuarine fisheries and early life stages of estuary-dependent marine fish, direct relationships of total seagrass and eelgrass Zostera m. capricorni areas and biomass with fish harvest were derived for a range of slightly to highly urbanized coastal lagoons that are expected to support the larvae and juveniles of estuary-dependent marine fisheries. Fish harvest and seagrass area and biomass in the lagoons increased with moderate catchment total suspended sediment and total phosphorus loads due to lagoon flushing rates directing excess silt and nutrients out to sea via the lagoon entrances. Well managed, sewered catchment management works are shown that could assist estuary managers maintain seagrass for estuarine and offshore estuary-dependent fisheries by maintenance of seagrass and fishery ecological processes. Further research is suggested to investigate estuary-dependent post-juveniles leaving estuaries and lagoons migrating to nearshore, offshore and shelf marine fisheries. •Coastal lagoon seagrass for larvae and juveniles of estuary-dependent marine fish.•Relationships of Zostera m. capricorni areas and biomass with fish harvest.•Increased seagrass and fish harvest with moderate sediment and phosphorus loads.•Increases aided by flushing rates transport nutrients to sea via lagoon entrances.