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Executive Summary
A range of benthic community types was described within the Mackay port limits in
February 2001. Three seagrass meadows, five algae community types and eight benthic
macro-invertebrate region types were identified.
The majority of the port limit area was dominated by bare substrate with a low density of benthic life. Higher-density benthic macro-invertebrate and algae communities occurred in proximity to the harbour and approach channels. The density of benthic life within the Mackay port limits appears to be typical of areas to the north and south ofthe port limits that have been surveyed.
Smaller areas of higher benthic habitat complexity were commonly found around reefs
and islands and in several patches in deeper offshore waters.
The majority of the works proposed for the harbour and approaches in the port
development plan appear to be located in areas that would cause minimal impact on
Mackay’s marine environment. The proposed southern approach channel, northern
harbour reclamation and future Cape class berths were all in areas of low-density benthic macro-invertebrate and algae communities.
Areas of the harbour that would require capital dredging as part of proposed port
expansion did not contain any significant benthic communities.
Both offshore berth options passed through areas of high-density benthic habitat and
further options for their location or management of impacts associated with their
construction may need to be considered.
Seagrass was unlikely to be affected by proposed port developments, as there were no
meadows in proximity to the harbour or approach channels.
Seagrass, algae and benthic communities described in this survey are likely to be
dynamic both seasonally and inter-annually.
Timing of any dredging works should be performed so as to cause minimal disturbance
to fish spawning and migration. Advice on localised fish movements and issues should
be sought from local fisheries representatives, Sunfish and Queensland Seafood Industry Association when determining the most appropriate time for capital dredging to be conducted.
The higher density algae and benthic macro-invertebrate communities at the mouth of the harbour still contained significant areas of open substrate. It is possible that an approach channel could be placed through this area without a major disturbance to these communities. An intensive survey of the proposed approach channel for approximately 1km from the harbour entrance would help to determine the level of any impact and may aid in the appropriate placement of the channel through this area.
The complete Report can be Downloaded
Here (Adobe Acrobat 1.47 MB).
For a full copy of this report please email CRC Reef info@crcreef.com.
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