Seagrass meadows are highly productive environments that provide valuable habitat for juvenile fish, prawns and other marine life.
Usually, these environments can withstand some disturbance, but the sheer scale of loss and their isolation from other meadows – which usually help replenish damaged grasses – means that seagrass recovery has not occurred in Mourilyan Harbour.
Mourilyan Harbour is a beautiful part of the world. It is characterised by shallow mudflats and deeper channels and is fringed by mangrove wetlands, providing a diverse array of habitat for marine and estuarine fish and invertebrates.
The estuary is located in far North Queensland, approximately 15km south-east of Innisfail, and 100 km south-east of Cairns, and is similar in size to Trinity Inlet (Cairns).
Seagrasses grow in the lower section of the Moresby River (a short coastal catchment in the wet tropics, located within the broader Johnstone drainage basin) and this area is listed as a nationally important wetland habitat.
The harbour is the main shipping port for sugar cane from the Tully and Innisfail regions. There is also a boat ramp that provides professional and recreational anglers with access to the estuary and adjacent offshore reefs and islands.
The health of the waterway is monitored routinely for the Wet Tropics Waterways annual report card. Seagrass health has been graded as Very Poor for a number of years, and this project aims to improve the health of seagrasses and the productivity of the estuary.
Project volunteers are helping attach and deploy seagrass fragments (vegetative sprigs).
For the past three years we have been working with JCU researchers to trial novel seagrass (Zostera muelleri) restoration techniques at the project site in Mourilyan Harbour. The seagrass is attached to biodegradable, potato starch frames before being deployed in the Harbour.
Our restoration trials in Mourilyan Harbour will continue through the following tropical dry and wet seasons. Together with our project partners, we are delivering an improved understanding of seagrass restoration in the Australian tropics and our work at this project site will inform future restoration efforts in the region.
Global coverage of seagrass is declining due to a combination of natural and man-made processes including floods, cyclones and coastal development.
Seagrass meadows are typically resilient to natural disturbances, however increasing pressure from coastal development has led to declining abundance, particularly in areas with high pressure from human disturbance. Assisting recovery is important to aid the restoration of seagrass meadows, and recreational fishers are increasingly helping to improve the health of seagrass in Australia.
TropWATER (JCU) and OzFish project team at the project site conducting drone monitoring
Seagrass growth from transplanted fragments.
The restoration of seagrass meadows in North Queensland continues to grow but volunteers are needed to ensure this year’s projects at Cairns and Mourilyan Harbour are a success.
A team of scientists and volunteers is racing to give nature a helping hand in Queensland's tropics — if nature's deadliest creatures don't get to them first. When Cyclone Yasi tore through the picturesque Mourilyan Harbour south of Cairns a decade ago, the category five monster system destroyed seagrass meadows that provided vital food and shelter for marine life. Researchers from James Cook University, Indigenous rangers and volunteers are harvesting hundreds of the plants off the coast of Cairns and replanting them in the harbour to re-establish the meadows.
Mourilyan Harbour, an estuary just south of Cairns, has been a focus site for scientists and OzFish volunteers over the last few months. Here, the objective has been to bring back the seagrass meadows that were lost over a decade ago following damaging monsoon rainfall. Seagrasses are an amazing nursery ground for some key recreational fish species in North Queensland including barramundi and mangrove jack. They are also critical to healthy waterways and marine environments as they filter sediment and nutrients from coastal waters, are a food source for turtles and dugong, and store carbon in their sediments. The meadows in Mourilyan Harbour were once thriving fish habitats full of juvenile prawns and fish but they have since been badly degraded.
Restoring a seagrass meadow in Far North Queensland can be a bit like trying to garden on a lawn filled with deadly snakes and spiders — you would not set foot in it. It is the equivalent of these dangers facing James Cook University scientists as they trial new techniques to restore a seagrass meadow in Mourilyan Harbour south of Cairns, home to crocodiles and deadly jellyfish. "We knew we were going to have to be able to deploy this from a boat because we can't get in the water there," said Associate Professor Michael Rasheed.
A pilot project to restore seagrass meadows at Mourilyan Harbour, south-east of Innisfail, has started with input from local recreational anglers and university researchers. The trial will assess the success of a unique seagrass restoration technique deploying seagrass fragments (sprigs) attached to mesh frames into a designated section of the harbour. The work is a collaboration between James Cook University’s Seagrass Ecology Group and Australia’s fishing conservation charity OzFish Unlimited. OzFish Senior Project Manager, Dr Geoffrey Collins said the work was an important step toward restoring seagrass meadows. “As recreational fishers, we understand the importance of seagrass to ecosystem health and to fisheries productivity,” ...
