Port Expansion Project EIS Appendix K2 Marine Ecology Baseline Report A part of BMT in Energy and Environment Port of Townsville Port Expansion Project EIS – Marine Ecology Baseline Report R.B17733.001.03.doc November 2012 Townsville Port Expansion Project EIS – Marine Ecology Baseline Report Offices Brisbane Denver Mackay Melbourne Prepared For: Port of Townsville Ltd Newcastle Perth Sydney Prepared By: BMT WBM Pty Ltd (Member of the BMT group of companies) Vancouver G:\ADMIN\B17733.G.GWF_POT_EXP\R.B17733.001.03.DOC DOCUMENT CONTROL SHEET BMT WBM Pty Ltd BMT WBM Pty Ltd Level 11, 490 Upper Edward Street Document : R.B17733.001.03.doc Brisbane 4000 Queensland Australia PO Box 203 Spring Hill 4004 Project Manager : Greg Fisk Tel: +61 7 3831 6744 Fax: + 61 7 3832 3627 ABN 54 010 830 421 Client : AECOM www.wbmpl.com.au Client Contact: Glenn Stephens Client Reference Title : Townsville Port Expansion Project EIS – Marine Ecology Baseline Report Author : Dr Darren Richardson, Dr Conor Jones, Dr Beth Toki, David Barnes Synopsis : This report forms a technical appendix to the Port of Townsville Port Expansion Project EIS. The report provides a description of marine ecological values within Cleveland Bay that could potentially be affected by the proposed port development, and will form the basis of the Existing Environment description for the Port Expansion Project EIS. REVISION/CHECKING HISTORY REVISION DATE OF ISSUE CHECKED BY ISSUED BY NUMBER 0 01/04/2011 DLR CMJ 1 12/06/2012 DLR CMJ 2 14/06/2012 DLR CMJ 3 26/07/2012 DLR CMJ DISTRIBUTION DESTINATION REVISION 0 1 2 3 POTL PDF PDF PDF PDF AECOM PDF PDF PDF PDF BMT WBM File PDF PDF PDF PDF BMT WBM Library PDF PDF PDF PDF G:\ADMIN\B17733.G.GWF_POT_EXP\R.B17733.001.03.DOC EXECUTIVE SUMMARY I EXECUTIVE SUMMARY Background This technical appendix to the Port Expansion Project (PEP) Environmental Impact Statement (EIS) describes the existing marine flora, fauna and biodiversity values of environments potentially affected by the Project and the wider Cleveland Bay region. The report specifically considers the three main areas (collectively referred to as the study area) potentially affected by the Project, namely the: outer harbour Project area; navigation channels subject to capital dredging for the Project; and existing offshore dredged material placement area (DMPA). This report summarises existing information regarding the environmental values of the study area and surrounds (i.e. Cleveland Bay), primarily focusing on marine habitats and communities, threatened species and fisheries resource values. The report also describes the methodology and findings of field investigations undertaken by BMT WBM to support the EIS chapter, which included the following: Seabed habitat mapping using acoustic (sonar) based techniques; Sediment and epifauna community assessments within representative seabed habitat classes, using a remotely operated underwater video system and grab sampling; Sampling of macrobenthic communities based on grab-sampling techniques; and Surveys of breakwater habitats and natural reef systems using a diver-operated underwater video system. The objective of these studies was to characterise sensitive ecological receptors, benthic habitats and communities within the study area and surrounds. Surveys were carried out within and adjacent to the Project areas and representative ‘control’ areas elsewhere within Cleveland Bay. Marine Vegetation Seagrass, mangroves, saltmarsh, benthic algae, together with corals, represent benthic primary producer habitat (BPPH). BPPH play an important role in maintaining coastal ecosystems and associated ecological services, including the provision of food and habitat resources for species of fisheries and conservation significance. BPPH is also sensitive to disturbance and water quality degradation, particularly light limitation. There are no mangrove and saltmarsh areas within the Project areas. Both of these wetland habitats occur adjacent to the outer harbour Project area at the mouth of Ross River, outside the likely zone of potential impact of the Project. The nearshore and deep-water seagrass meadows of Cleveland Bay are considered to be among the largest in the central Queensland coast. Seagrass surveys carried out in the 2000s show that the extent and biomass of seagrass within Cleveland Bay varies greatly over time. Temporal changes in seagrass meadows reflect seasonal and inter-annual variability in physical disturbance and turbidity. G:\ADMIN\B17733.G.GWF_POT_EXP\R.B17733.001.03.DOC EXECUTIVE SUMMARY II Nonetheless, the seagrass meadows of Cleveland Bay are considered by the Department of Agriculture, Fisheries and Forestry to be largely unaffected by port operations. No seagrass has been recorded to date within or directly adjacent to the outer harbour Project area. Surveys carried out in 2008 recorded a low-density deep-water seagrass meadow throughout much of the Cleveland Bay, including parts of the DMPA, and directly adjacent to Platypus and Sea Channels. This meadow represents a transient feature, and was not recorded in 2009-2011 surveys. Nonetheless, the area occupied by this seagrass meadow is considered to represent potential seagrass habitat. Seagrass species differ in their sensitivity to disturbance (i.e. resistance) and capacity to recover following disturbance (i.e. resilience). In general, small species such as Halodule and Halophila tend to have low carbohydrate reserves compared to larger species, and are therefore the most sensitive species to low light conditions (i.e. low resistance). However, Halodule and Halophila species also have adaptations that allow rapid recovery (i.e. high resilience). Larger species such as Zostera muelleri and Cymodocea serrulata have high resilience to low light conditions, but are slower to recover should they be lost. The capacity to recover following disturbance also depends on seagrass condition, which is a function of the previous disturbance history (magnitude, and spatial and temporal scale of disturbance). Successive periods of disturbance (i.e. multiple wet years) have depleted seagrass energy sores, seed banks and standing crop (i.e. seagrass condition), which greatly decrease the capacity for seagrasses to recover following disturbance. The Reef Rescue Marine Monitoring Program assessed the condition of seagrass meadows based on a range of indicators. Seagrass meadows of the Burdekin-Townsville region were classified as being in a ‘poor state’ throughout the 2009/10 monitoring period (Johnson et al. 2011). Successive wet periods since 2007 have reduced the condition of seagrass meadows and their capacity to recover from disturbance. This is particularly the case of seagrass meadows around Magnetic Island, with mainland meadows displaying a higher capacity to recover. Reefs Habitats and Communities Cleveland Bay supports numerous reefs, including the fringing reefs of Magnetic Island, Middle Reef Virago Shoal. Middle Reef has particularly high hard coral cover, varying between 19 and 84% cover at/ondifferent parts of the reef. Coral cover and community structure varies greatly among reefs and between depth strata within reefs at Magnetic Island. Highest hard coral cover typically occurs on reef slopes, whereas the reef flats are typically dominated by macroalgae and seagrass (particularly at Cockle Bay Reef). Long term monitoring suggests that coral cover fluctuates over time, with major reductions observed after cyclone events such as Althea, Bronwyn and Yasi. Macroalgae typically dominates reefs shortly after such disturbances. Cleveland Bay coral communities are subject to a range of environmental pressures. Low salinity flood waters in 2009-2011, as well as physical disturbance by Cyclone Yasi, are likely to be the main drivers of recent declines in coral cover in Cleveland Bay. Numerous coral bleaching events have been observed at Magnetic Island reefs, mostly in response to high seawater temperatures. Low salinity conditions also promote disease incidence in Magnetic Island coral communities. G:\ADMIN\B17733.G.GWF_POT_EXP\R.B17733.001.03.DOC EXECUTIVE SUMMARY III Like seagrass, coral species differ in their sensitivity to disturbance (i.e. resistance) and capacity to recover following disturbance (i.e. resilience). In terms of resistance, Cleveland Bay has naturally high turbidity levels and therefore corals must have adaptations to cope with periods of low light and high sedimentation rates. The degree of resilience of corals varies among taxa. Acroporidae corals, for example, can show great changes in cover over time but are generally considered to be resilient. While most Acroporidae species are photophilic (sensitive to light deprivation) and break easily, they are also capable of high growth rates and high reproductive output (Thompson et al. 2010). Coral reefs of the Cleveland Bay are thought to be resilient to change, showing rapid recovery following disturbance. Notwithstanding this, recovery rates and growth of corals are highly dependent on ambient environmental conditions. In recent years, Thompson et al. (2011) recorded low levels of coral recruitment (predominantly by slow-growing coral species) on settlement plates located at Middle Reef. On the basis of these results, Thompson et al. (2011) suggested that conditions in the last few years would not facilitate rapid recovery following any catastrophic disturbance. However, the degree of resilience is expected to improve as communities recover from the successive climatic disturbances in recent