2022-11-08 P&E Agenda - Item 6 - Attachment 1 - Current & Historical Distribution of Seagrass in the Noosa Estuary (40 pages)

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substrates. These habitats had low epifaunal activity (no burrowing crabs were observed in
the sand), with a low density of burrows on the surface (average <1 m-2), and no epibenthic
fauna (such as sea cucumber, bivalves or sea pens) were recorded in the georeferenced
videos or along photo transects. The coarse sandy habitat was unconsolidated and highly
mobile due to strong tidal currents, which likely reduced the suitability for fauna that burrow
into the sediment. Results from the field survey are consistent with studies from the wider
region, which generally recorded low abundances of epibenthic fauna from non-vegetated
soft substrates (Skilleter- et al. 2019).
Stingrays and fish were recorded in the non-vegetated soft sediment habitats in and around
the study area, and numerous stingray pits occurred intertidally, particularly in channel
habitat and at the mouth of Lake Weyba. Large drifts of seagrass wrack (i.e. dead seagrass
fragments detached from the original plant) were not evident throughout the estuary.
Seagrass wrack is an important component of coastal ecosystems, providing microhabitats
and food resources for fauna, and contributing to nutrient cycling (Oldham et al. 2014).




    Figure 3.5 Z. muelleri with dense epiphytic algae in Weyba Creek in November 2020




Assessing Distribution of Seagrass in the Noosa Estuary                                                  11