South African temporarily open/closed estuaries (TOCEs) and similar systems along the coastlines of other regions of the world, especially Australia, are amongst the most productive aquatic ecosystems. They shift seasonally from mostly open mouth states during rainy seasons to mostly closed mouth states during the dry part of the year. This allows a whole range of juvenile forms of estuarine-dependent and estuarine-associated marine species to be recruited inside their sheltered and productive reaches, where they complete their growth to maturity. This book covers topics such as the structure and function of open/closed estuaries in South Africa, as well as outlining the future management decisions that need to be made in order to ensure the longevity of these productive ecosystems.