Expanding fish productivity in Tasmanian saltmarsh wetlands through tidal reconnection and habitat repair

Fish use of coastal saltmarsh wetlands has been documented for many parts of Australia with the notable exception of Tasmania. An initial investigation to examine the diversity, density and patterns of fish use in the Circular Head coast saltmarshes of north-west Tasmania was undertaken. To aid decision making in repair strategies, the effect of saltmarsh condition on fish assemblages was studied using paired sites of predominantly unaltered and altered saltmarshes where levees were present. In all, 851 fish from 11 species were caught in 37 of the 48 pop nets. Three species, Aldrichetta forsteri, Arripis truttaceus and Rhombosolea tapirina, are important to commercial and recreational fisheries and contributed ~20% of the total catch numbers. The mean density of >72 fish per 100 m2 is the highest yet reported from Australian studies and indicates that Tasmanian saltmarshes provide higher value habitat for fish compared with elsewhere in Australia, likely due to more frequent and prolonged flooding, and the lack of adjacent mangroves. There was no significant difference in fish assemblages between unaltered and altered marshes. The results suggest that restoring basic saltmarsh structure through tidal reconnection will deliver substantial benefits for fish productivity through habitat expansion.

Document type: