Small seine net fish assemblages in the headwater region of the Kariega Estuary are described and compared to the catch composition in other parts of the system. The geographical headwaters of the freshwater ‘deprived’ Kariega Estuary were utilised by a range of fish species but, in contrast to the nearby freshwater ‘rich’ Great Fish Estuary, few important angling species (e.g. spotted grunter ...

Tidal dynamics of shallow estuaries and lagoons is a complex matter that has attracted the attention of a large number of researchers over the last few decades. The main purpose of the present work is to study the intricate tidal dynamics of the Tagus estuary, which states as the largest estuary of the Iberian Peninsula and one of the most important wetlands in Portugal and Europe. Tagus has la...

An understanding of sediment transport processes and resultant concentration dynamics in estuaries is of great importance to engineering design awareness and the management of these environments. Predictive modelling approaches provide an opportunity to investigate and address potential system responses to nominated events, changes, or conditions of interest, often on high temporal and spatial ...

A rapid ecological water requirement study of the Department of Water Affairs in 2009 classified the Goukamma Estuary as largely natural with few modifications, i.e., in an A/B state. However this detailed 13-month study showed that the estuary is impacted. Salinity stratification and hypoxic conditions (dissolved oxygen (DO) < 3 mg∙l-1) were measured during both open and closed mouth states. T...

Natural patterns of zooplankton variability (temporal and spatial) in the Kromme Estuary have broken down due to persistent euhalinity (salinity values above 28‰) throughout the estuary. These conditions occur as a consequence of freshwater retention by a large reservoir. Only 2 x 10 m (<2% of the mean annual runoff (MAR) from the catchment) is allocated to the estuary per annum, and the presen...

A numerical simulation of circulation in the Columbia River estuary and plume during the summer of 2004 is used to explore the mixing involved as river water is transformed into shelf water. The model is forced with realistic river flow, tides, wind stress, surface heat flux, and ocean boundary conditions. Simulated currents and water properties on the shelf near the mouth are compared with rec...

The salinity budget in a 3-D numerical model of an estuary is analyzed using isohaline surfaces to define the volume of integration. Such surfaces move with the currents, and as a result of turbulent mixing. The isohaline analysis allows us to clarify the processes which create and destroy water in different salinity classes in the estuary. We find that the estuary naturally divides into three ...

The adjustment of estuarine circulation and density to changes in river flow and tidal mixing is investigated using analytical and numerical models. Tidally averaged momentum and salinity equations in a rectangular estuary are vertically averaged over two levels, resulting in equations that are analytically tractable while retaining a broad range of time-dependent behavior. It is found that bot...

The interactions of circulation and growth processes in determining the horizontal distribution of eastern oyster (Crassostrea virginica) larvae in the Delaware Bay estuary were investigated with a coupled circulation-individual-based larvae model that used environmental conditions from the spawning seasons (mid-June to mid-September) of 1984, 1985, 1986, 2000, and 2001. Particles, representing...

Assessment of the ecological quality of theMinho estuary (Northwest Iberian Peninsula) based on metal concentrations in sediments and in Corbicula fluminea The concentrations of metals (Cd, Cr, Cu, Fe, Ni, Pb and Zn) in sediments and the soft tissues of Corbicula fluminea from the Minho estuary (Northwest Iberian Peninsula) were determined to assess the spatial variation of metal bioavailabilit...