Mangroves play a vital role in reducing the amount of waste entering the ocean by capturing nutrients, sediments and pollutants. Port of Brisbane is located adjacent to some of the largest mangrove ecosystems in Moreton Bay.
Since 1999, PBPL has monitored the ecological health, species composition and structure of the mangroves adjacent to the port. Monitoring takes place annually and includes field surveys, GIS mapping and photographic monitoring to identify changes over time.
Data collected from the monitoring since this time indicates that the health of the mangrove community has declined during the monitoring period, with fluctuations in health caused by severe weather events (drought and floods) and changes in the quality of water in Moreton Bay.
Latest monitoring and research (at a glance)
The most recent mangrove health monitoring was conducted in 2019.
The 2019 monitoring mapped changes between 2018 and 2019 using remotely sensed data and ground surveys.
Between 2009 and 2019, there was a net seaward and landward expansion of mangrove forests at Fisherman Island and Whyte Island and a commensurate reduction in saltmarsh/saltpan habitat.
Cyclic changes in NDVI (spectral index estimating green biomass) were consistent with long term analysis of Landsat imagery, with higher values of canopy chlorophyll in winter then summer months.
A strong correlation between rainfall and mangrove health was consistent with historical data.
Some highly localised bank erosion and mangrove falls were observed at Bulwer Island where works have been conducted to improve fish habitat connectivity.
In 2016, PBPL embarked on a research program in partnership with the Moreton Bay Seafood Industry Association to develop an assessment tool to predict the value of mangroves and other marine habitats for commercial fisheries.
The research highlighted that the interconnectedness of different marine habitats is crucial to maintaining high numbers of commercially valuable fisheries species.
2019 Mangrove Health Assessment Report
In 2016, PBPL worked with Moreton Bay Seafood Industry Association in order to develop a tool to assess the value of coastal seascapes that are adjacent to the Port of Brisbane.
The study showed that seagrass communities are more important than mangrove communities for predicting the value of commercial fisheries adjacent to the Port of Brisbane.
2017 Coastal Seascapes for Commercial Fisheries Production
Seagrass is an important flowering marine plant that forms meadows in shallow, sheltered waters.
Seagrass meadows provide important habitat and food for many marine animals including dugongs, turtles, sea urchins, fish, shore and water birds and benthic fauna. There is a large seagrass meadow adjacent to the Port of Brisbane, which has a considerably high biodiversity value.
Since 1991, Port of Brisbane has conducted regular monitoring of this seagrass meadow. The health of seagrass meadows is determined using aerial photography, survey transects and underwater video surveys to assess the seagrass depth range and undertake community profiling and meadow mapping.
Monitoring results show the construction of the Port’s reclamation area has benefitted the growth and health of the seagrass communities by protecting the seagrass in Waterloo Bay from prevailing winds and separation from the mouth of the Brisbane River.
So much so that since 1991, the seagrass meadows adjacent to the Port have increased by 200% and now cover 1,400 hectares.
Latest monitoring (at a glance)
The most recent seagrass monitoring occurred in 2019.
Results show that the meadows located adjacent to the port continue to expand and recover from damage that occurred as a result of the 2011 and 2013 floods.
Seagrass adjacent to the Port of Brisbane are at the highest extents ever recorded.
The results continue to show that port activities are having little impact on seagrass at Fisherman Islands, with seagrass meadows at Fisherman Islands considered to be in a good condition.
Intertidal and shallow subtidal areas were predominately composed of Z. muelleri (a type of seagrass commonly referred to as eelgrass or garweed) meadows. Deeper subtidal meadows were dominated by Halophila species (characterised by tape-grass appearance). This is consistent with previous years.
Algae continues to impact on seagrass with high algae cover likely due to nutrient enrichment from the Brisbane River.
2019 Seagrass Monitoring Report
Future Port Expansion seawall
Port of Brisbane’s Future Port Expansion (FPE) seawall, located in the Port’s reclamation area was completed in 2005 and extends over 4.6km.
Over time, the FPE seawall has become an important habitat for a diverse range of benthic flora and fauna communities, supporting a vast array of marine life including macro-algae, corals, sponges, anemones, crayfish and fish.
Monitoring is undertaken every five years to investigate the quality and extent of this important habitat within the wall. Data is gathered through field surveys using transects and underwater cameras to assess changes over time.
Latest research (at a glance)
The most recent monitoring was undertaken in 2019
Results show the FPE seawall continues to support benthic flora and fauna communities, consistent with the 2014 survey.
The FPE seawall was also identified as an important habitat for local fisheries. The crevices in the wall and high macro-algae cover provides shelter for small reef dwelling species (crayfish, sea urchins, soft and hard corals etc.) and large schools of fish that are of direct significance to commercial fisheries.
The latest survey also trialled eDNA sampling. eDNA is genetic material obtained directly from environmental samples such as water and is an accurate measurement of what species have moved through an area. This method proved to be highly successful with at least 23 species detected in the first round of sampling including; Mullet, Parrotfish, Dusky flathead and a Green Turtle.
2019 Future Port Expansion Seawall Ecological Assessment