Fishes and benthos of near-shore seagrass and sandflat habitats at Monkey Mia Shark Bay, Western Australia

Brief description

In February and June 1983, fishes and benthic fauna were sampled to provide quantitative estimates of densities and volumes of the benthic invertebrate animals and biomass of the seagrass in summer, as well as abundances of the fishes occurring during the day and night and in both summer and winter in Amphibolis seagrass beds and sand flats at Monkey Mia Shark Bay, Western Australia.

Lineage

Maintenance and Update Frequency: notPlanned

Statement: - Study site - The study conducted at the "Subtidal site" (see thumbnail) to the west of the Monkey Mia Caravan Park on the Peron Peninsula of Shark Bay, Western Australia. During extreme spring tides in summer the sand flats and beds of Amphibolis around this site are exposed, but they remain flooded during neap tides and the winter spring tides. - Samples of fishes - The equipment was a 14 m wide seine of 8 mm stretch mesh, 1.8 m high, with a footrope of light chain, a headrope with enough floats to keep the top of the seine at the surface and with a pocket in the middle extending 3.5 m from the footrope to the cod end. The seine was carried to location of the sample and hauled 50 paces (38 m) with the ends of the seine 10 m apart, on average, and brought the wings together rapidly and lifted the entrance to the cod end out of the water and carried the trapped fish back to shore. On shore the catch were emptied and identified and all individuals counted. The entire catch of early samples were preserved to confirm identifications and retain voucher species. Rarer were kept in later samples but most individuals of abundant species were released. The design of the seining scheme was to sample the two habitats ((intertidal beds of Amphibolis and adjacent sand flats), at two times (day and night)) and at two seasons (summer (14-16 February 1983) and winter (26 June 1983)); 3 replicate samples for each of these eight categories, making 24 seine hauls in total. - Samples of benthos - On 15 and 16 February 1983 ten 1 m2 areas as described in Peterson and Black (1987) by excavating the top 10 cm of sediments with fingers to remove the large animals and by sieving these sediments through a 3 mm metal sieve to remove the smaller animals. Graduated cylinders were used to determine the displacement volume of all the individuals of each species. Also, on 14 and 15 February 1983 we used a 27 cm diameter metal pail with the bottom removed as a coring device to take samples of 0.057 m2, 20 cm deep. Material from six cores taken from the beds of Amphibolis were sieved through a 1 mm square-mesh screen and counted and measured the volume of the animals, of the above - and below - ground portions of the Amphibolis and of the detrius, as described previously for the animals on the sand flats. On 15 February 1983 a small plastic coring device 85 cm2 in area and 15 cm deep was used to collect 6 samples of the seagrass which was weighed after shaking to remove superficial water. ***References***Paterson, C. H. and Black, R. (1987). Resource depletion by active suspension feeders on tidal flats: influence of local density and tidal elevation. Limnol. Oceanogr. 32: 143-166.

Notes

Credit
School of Animal Biology, The University of Western Australia (UWA)