Marine Plant Assessments

What is a Marine Plant Assessment?

A marine plant assessment evaluates the presence, extent, and ecological significance of marine plants in areas proposed for development or disturbance. In Queensland, marine plants are defined under the Fisheries Act 1994 and include mangroves, seagrass, salt marsh (saltcouch), salt flats associated with marine plant communities, and other plants that grow in tidal areas below the highest astronomical tide (HAT).

Marine plants play a critical role in Queensland’s coastal and estuarine ecosystems. Mangrove forests stabilise shorelines, filter sediments, and provide essential nursery habitat for commercially and recreationally important fish and crustacean species. Seagrass meadows support dugong and marine turtle populations, contribute to carbon sequestration, and underpin coastal food webs. Salt marsh communities provide transitional habitat between terrestrial and marine environments and support a range of specialised plant and animal species.

The removal, destruction, or damage of marine plants is regulated under the Fisheries Act 1994 and assessed through SDAP State Code 23: Removal, Destruction or Damage of Marine Plants. Unauthorised damage to marine plants can create approval risk, enforcement issues and project delays, making early identification and assessment of marine plant values essential for any coastal or tidal development.

When Do You Need a Marine Plant Assessment?

Coastal Development

Any development in tidal areas or below the highest astronomical tide that may impact marine plants requires assessment under the Fisheries Act 1994. This includes residential and commercial development on coastal sites, foreshore works, seawall construction, and boat ramp installation.

Port and Marine Infrastructure

Port developments, marina construction, jetty and pontoon installations, and dredging operations in areas containing or adjacent to marine plant communities require marine plant assessment. These projects often involve significant areas of potential impact and may require detailed marine plant surveys and offset assessments.

Tidal Works and Coastal Engineering

Works within tidal areas including stormwater outfalls, drainage channels, revetment walls, and coastal protection structures may impact marine plants. Even works above HAT can require assessment where they may affect the hydrology or sedimentation patterns that sustain marine plant communities.

Aquaculture Development

Aquaculture developments in coastal areas frequently interact with marine plant communities. Assessment of marine plant values is required for pond construction, intake and discharge infrastructure, and access roads in tidal areas.

Resource Projects

Mining, gas, and infrastructure projects in coastal Queensland may impact marine plant communities through direct clearing, changes to tidal hydrology, increased sedimentation, or altered water quality. Projects involving LNG export facilities, port expansions, and pipeline crossings commonly require marine plant assessments.

Our Process

1. Desktop Review - We review available mapping data including coastal wetland mapping, marine habitat mapping, aerial imagery, and tidal datum information to identify the potential for marine plants within and adjacent to the project area. We determine the applicable regulatory framework and identify all relevant assessment triggers.
2. Marine Plant Survey - We conduct field surveys to map the distribution, species composition, and condition of marine plant communities. Survey methodology is tailored to the site and may include intertidal transects, quadrat sampling, drone mapping, and GPS delineation of community boundaries. We survey for all Fisheries Act marine plant categories including mangroves, seagrass, salt marsh, and associated salt flat communities.
3. Ecological Value Assessment - We assess the ecological significance of identified marine plant communities, considering factors such as community extent, condition, connectivity to other marine habitats, fisheries habitat value, and conservation significance. This assessment informs the impact evaluation and helps determine the level of regulatory scrutiny the project is likely to receive.
4. Impact Assessment - We evaluate the direct and indirect impacts of the proposed development on marine plants, including direct removal or disturbance, changes to tidal hydrology, increased sedimentation, altered water quality, and edge effects. We apply the avoidance and mitigation hierarchy to identify measures that can reduce or eliminate impacts on marine plant values.
5. State Code 23 Assessment - We prepare the assessment against SDAP State Code 23, addressing the purpose, performance outcomes, and acceptable outcomes for removal, destruction, or damage of marine plants. This includes demonstrating that impacts have been avoided where possible, that remaining impacts are minimised, and that offsets are provided for any significant residual impacts.
6. Reporting and Permit Support - We deliver a comprehensive marine plant assessment report and provide support through the development assessment process, including preparation of resource allocation authority applications, responses to information requests, and offset assessment where required.

Related Services

• Waterway and Wetland Assessments - freshwater and estuarine waterway and wetland ecological assessments
• Fish Passage and Waterway Barrier Works - fish movement and waterway crossing assessments
• Significant Residual Impact Assessments - determining offset obligations for marine plant impacts

Get a Quote

Queensland Ecologists provides marine plant assessments for coastal developments, port infrastructure, and tidal works across Queensland. Our team has experience surveying and assessing marine plant communities from the Gold Coast to North Queensland, and we understand the regulatory requirements of DAF and SARA for marine plant matters.

Contact us today for a no-obligation quote on your marine plant assessment.

Request a Quote Online or call us on (07) 3018 7538.