Until the nineteenth century, for example, bottlenose dolphins occurred in all the major estuaries in Britain, including the Thames and the Humber.

Viaducts: The line crosses several major estuaries - the rivers Kent and Leven being among them - over substantial viaducts.

The Hudson River may be the nation's most biologically productive major estuary, sustaining successful spawning populations of species like striped bass, shad and sturgeon, experts said.

Each major estuary along the coast has its own horseshoe crab population, distinguished from one another by size, colour and eye pigment.

Although there are no significant mountains to cross except the escarpment near the Queensland border, there are numerous major estuaries which will require long viaducts.

Eventually emptying into seven major estuaries, these rivers support over 212 reservoirs.

The threats to our major estuaries alone take up considerable time and effort.

It includes the Eastern Shore and major estuaries which enter the Chesapeake Bay.

There are also permanent fishing camps on the major estuaries.

As Dundee is located on a major estuary, it developed a maritime industry both as a whaling port (since 1753) and in shipbuilding.