Gladstone Permanent Transect Seagrass Monitoring: April 2011 update

Sankey, T.L., Hedge, S.A., McKenzie, L.J., McCormack, C.V., and Rasheed, M.A. (2011) Gladstone Permanent Transect Seagrass Monitoring: April 2011 update. Report. Department of Employment, Economic Development and Innovation, Cairns, QLD, Australia.

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This update report details the findings of the la test of the regular quarterly assessment of permanent seagrass transects in Gladstone conducted in April 2011 and an additional assessment in March 2011.

In April 2011 seagrass at permanent transects remained low in cover and biomass with no major changes since the last quarterly monitoring event (February 2011) or the additional survey in March 2011.

Some above-ground seagrass was present within permanent transects at all monitoring sites in April 2011 except for Wiggins Island where very small isolated patches of seagrass ( Halophila ovalis ) were sighted in the vicinity of the permanent transects.

A natural seasonal decline in seagrasses would norm ally be expected at this time of year (late summer to autumn) however the scale of decline in 2010/2011 was greater than seen in the previous year. Seagrass cover in November 2010 (the normal high season for seagrasses) was already lower than for previous years.

These changes in seagrass are consistent with observed climate conditions of high rainfall, river flows and low light conditions that occurred in 2010/11. Recent seagrass tissue nutrient results provide anecdotal evidence of these negative climatic conditions in Port Curtis and Rodds Bay. Similar declines in seagrasses have also been recorded at other east coast locations where seagrasses are being monitored.

Despite the declines at permanent transect monitoring sites, large areas of seagrass still remain in Port Curtis including the large Pelican Banks Zostera capricorni meadow.

The examination of seagrass seed bank status from samples collected in March 2011 show promising preliminary results. Numerous Zostera capricorni seeds were present in sediment cores collected at Wiggins Island and Pelican Banks and Halophila seeds have so far been found in cores collected at Fishermans Landing. The analysis of seed cores for Halophila seeds is ongoing but implications of results-to-date are promising in terms of resilience of meadows with seeds present. At this stage, the viability of seeds identified has not been established.

If climate conditions in the second half of 2011 are favourable for seagrass growth we would expect to see some recovery of seagrasses. Based on previous monitoring, seasonal increases in seagrass would not be expected to be apparent until June/July.

Item ID: 45896
Item Type: Report (Report)
Keywords: seagrass, monitoring, dredging, Gladstone, Port Curtis, Western Basin Dredging and Disposal Project
Related URLs:
Funders: Gladstone Ports Corporation (GPC), Fisheries Queensland (FQ), Department of Employment, Economic Development and Innovation (DEEDI)
Date Deposited: 28 Sep 2016 23:58
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050206 Environmental Monitoring @ 100%
SEO Codes: 96 ENVIRONMENT > 9605 Ecosystem Assessment and Management > 960503 Ecosystem Assessment and Management of Coastal and Estuarine Environments @ 100%
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