Tidal Inundation

 





Coastal saltmarsh occurs in intertidal zones that are permanently or intermittently open to inundation by marine tides and are frequently on the landward side of mangrove stands. The level of inundation is dependent on the elevation of the saltmarsh and the height of the tide. These factors then determine the length of time areas of saltmarsh are inundated with saltwater and consequently affects the physical conditions of the soil and suitability for various species of saltmarsh vegetation. The length of time of inundation also impacts on the availability of the saltmarsh habitat for visiting nekton species including fish and crustaceans. Most saltmarsh in the Moreton Bay region is subject to inundation only around the occurrence of King and Spring tides.

Video: Tidal Inundation and Toadfish!

 

Spring Tides

Saltmarsh is inundated during Spring tides providing foraging opportunities for fish as they move onto the normally inaccessible saltmarsh habitat. The common toadfish (Tetractenos hamiltoni) is one of the first species to make their way onto the marsh maximising their opportunities to exploit the new resources before other fish and nekton move in.

The opportunity to feed on the saltmarsh invertebrates including gastropod and shore crab larvae is limited and toadfish maximise their feeding time by moving in with the rising tide. Indeed toadfish are well designed to manoeuvre through shallow water and clumps of saltmarsh vegetation.