How are freshwater fish responding to the restoration of Long Swamp?

Freshwater fish are important indicators of environmental change, and a long-term study by Aquasave / NGT staff recently published in the journal Landscape Ecology, illustrated how they were used to explore the benefits of the hydrological restoration of Long Swamp, the Ramsar Convention listed coastal freshwater wetland complex in the southwest of Victoria.

Commencing in 2012, the fish monitoring program consisted of biannual sampling of the fish community over the pre-, during and post-restoration periods spanning an eight-year timeframe (2012–19). The fish monitoring, led by Lauren Brown, was a triumph of persistence, with harsh and changing conditions, complex site access and funding uncertainty, at times jeopardising its continuity.

But despite the challenges it did continue and led to an impressive dataset – almost 180,000 fish sampled from 19 species, with the catch mostly represented by native freshwater specialists and diadromous species (those that require connection between the ocean and freshwater environments to complete their lifecycle).

The complex logistics involved in sampling fish in Long Swamp.

Analysis of the changes over time revealed that restoring the natural flowpath of Long Swamp helped to enhance aquatic habitat and connectivity for the mostly native freshwater fish community that inhabits the wetland complex. By exploring how fish are responding, the study was able to demonstrate the benefits of wetland restoration, whilst highlighting that rehabilitation on this scale is complex and takes time. The study also showcased the importance of the freshwater coastal wetlands, which are an often neglected wetland type.

More information on the study can be found in the following publication:

  • Whiterod NS, Brown L, Farrington L, Bachmann M, and Vilizzi L, (2021). Long and lasting: spatial patterns and temporal trends in a fish community responding to landscape-scale hydrological restoration of a freshwater coastal wetland complex. Landscape Ecology, 36, 1511–1532.
A key fish monitoring location in the long-term study: the Long Swamp restoration trial structures in 2015, at the (now closed) Nobles Rocks artificial outlet. Photo: Marcel Hoog Antink
Nick Whiterod