| Summary: | Maintenance and Update Frequency: unknown Statement: Study sites Fish were collected from the intertidal region of three estuaries: Port Wakefield (138.144◦E, 34.189◦S), Port Broughton (137.926◦E, 33.598◦S) and Port Pirie (138.016◦E, 33.149◦S), South Australia .These estuaries are tide-dominated habitats characterised by extensive mangrove forests composed of Avicennia marina and large areas of intertidal mudflats. These mudflats consist of patches of Zostera muelleri seagrass interspersed with non-vegetated sand and mud substrate. Avicennia marina covers 12.8 km2 at Port Pirie, which is a significantly greater area than that at Port Wakefield and Port Broughton (1.4 km2 and 1.2 km2 respectively). Collection of fish Sampling was undertaken during the austral summer of 2005/2006. Fish were sampled at each estuary using eight fyke nets (the maximum number available).The nets consisted of four 0.7m×0.7m frames, around which 6-mm mesh was attached .A mesh wing of 0.7m×6m was fixed to each side of the net opening. Floats and lead weights were attached to the top and bottom of the wings, respectively. The nets were aligned with the wings parallel to the mangrove fringe with the net opening facing the shoreline. Wooden garden stakes were used to secure the flaps and ends of the nets to the sediment. Samples were taken from six distance classes, ranging from within the mangroves to ∼500m seaward of the mangrove fringe. During low tides, water retracted completely from each distance class such that fish could not enter the nets. Study design All eight nets were set at an estuary within 1 h of low tide and samples were collected 24 h later, thus exposing the nets to two tidal cycles. Sampling days were randomly dispersed among the three estuaries. The eight nets were randomly assigned to the six distance classes of an estuary simultaneously on each sampling day until a total of five replicates were taken at each distance class within each estuary. Fish were quantified and identified to species in the field where ...
|
|---|