Distribution and abundance of seagrass in the Torres Strait (T2.3)
Dr Stuart Campbell, Dr Rob Coles, QDPI

The Torres Strait has some of the most extensive seagrass meadows in northern Australia. These meadows support threatened species as well as fisheries resources. Long-term weather patterns and extreme flood and cyclone events influence the dynamics of seagrasses because they affect the light available which is pivotal to seagrass survival.

There was a recent seagrass dieback in the north-western region of central Torres Strait. To predict the consequences of such disturbance on seagrass habitats, we need information about the distribution of seagrasses and characteristics of seagrasses (eg. physiological and morphological responses) in different habitats.

This task will study seagrass communities throughout the Torres Strait including the open sea floor, adjacent to continental islands on reef flats and in intertidal zones. We will determine the distribution, status and functioning of seagrass habitats that will be pivotal to modeling the effect of processes such as flood plumes and sediment movement on seagrass habitats. We will develop maps of seagrass habitats to managers and communities so that we can determine if seagrass is recovering in areas where there has been loss. These maps will also be useful as resource maps for dugong, turtle and commercial fisheries.

The task links with other tasks aiming to understand key ecosystem processes and causes of seagrass die-back.

Objectives

• Improve understanding of ecological sustainability and conservation of threatened marine species in the Torres Strait by providing information about the distribution and abundance of intertidal and subtidal seagrass communities.
• Quantify productivity of intertidal and subtidal seagrasses in the central Torres Strait to better understand factors that affect growth and survival.
• Provide information in a GIS format (with available metadata tables) to develop a knowledge base of seagrass ecosystems in the Torres Strait and to support regional marine planning.

Outcomes

• Baseline knowledge including maps of seagrass communities and assessments of seagrass production and condition.
• A toolbox of information and sampling tools that will help Torres Strait people to assess distribution of seagrasses, and changes in seagrass condition.
• A toolbox of information to improve decision making for the management of marine resources in the Torres Strait to assist with sustainable management of culturally important threatened species, particularly dugong and turtle.