A paper published this week highlights the importance of healthy saltmarsh ecosystems for fish.
The paper, penned by Vishnu Prahalad, Violet Harrison-Day, Peter McQuillan and Colin Creighton, titled Expanding fish productivity in Tasmanian saltmarsh wetlands through tidal reconnection and habitat repair, focused on studies conducted in the extensive saltmarsh ecosystems of the Circular Head area, where about one quarter of Tasmania’s saltmarsh grows.
Sites were selected in undisturbed saltmarsh, and in “altered” saltmarsh, where human activities such as drainage ditches, vegetation clearing, cattle grazing, and tidal alteration by levees, have taken place.
In Tasmania, this habitat is thought to be even more important than in other parts of Australia, because Tasmanian coastlines do not have mangrove ecosystems (known to act as fish “nurseries” elsewhere).
Cradle Coast Authority NRM’s Coastal Coordinator, Anna Wind said: “We already knew that removing weeds like Spartina anglica (Rice Grass) from saltmarsh was important, because many birds including threatened species like Orange-bellied Parrots and Eastern Curlews need healthy saltmarsh to feed in.”
“Thanks to Vishnu’s work, we now also realise how important saltmarsh is for marine fisheries.”
Saltmarsh is listed as a Threatened Ecological Community under Australia’s Environmental Protection and Biodiversity Conservation legislation.
During the study, 851 fish of 11 species were caught in the intertidal area. Twenty per cent of the fish caught were commercially valuable species. Fish need saltmarsh because it provides a sheltered habitat, it is rich in food sources, and offers protection to juveniles.
Even in altered saltmarsh, fish were found if there was good tidal connectivity. This suggests that maintaining tidal movement and undertaking targeted tidal restoration would be valuable activities.
UTAS researcher and lecturer Dr Vishnu Prahalad is an expert in saltmarsh and wetland ecology. His research and teaching focusses on supporting NRM organisations and community groups to foster sustainable systems of production and consumption.
Cradle Coast Authority’s NRM team will use Dr Prahalad’s work to develop a saltmarsh rehabilitation project across the north-west natural resource management region.
Read the paper here