Otago's estuaries have received a mixed report card from the Otago Regional Council.
Tautuku Estuary in Otago Photo: Supplied / Otago Regional Council
The council has studied the health of eight estuaries in the region with some in good health while others are showing signs of degradation.
The Tokomairiro near Milton and Kaikorai in Dunedin were singled for concern.
Otago Regional Council coastal scientist Dr Sam Thomas said the results - which were recently published on LAWA's website - showed Otago's estuaries were a mixed bag.
"Tautuku Estuary [in the Catlins] is a stunning area that represents an important reference site against which long-term changes in other similar estuary types across the Otago region can be compared, largely because of the excellent quality of its freshwater inputs and due to 97.9 percent of indigenous vegetation still remaining in the catchment," he said.
Otago Regional Council scientists working at a Blueskin Bay monitoring site. Photo: Supplied / Otago Regional Council
Estuaries were important ecosystems and habitats for plants and animals.
"Papanui inlet and Blueskin Bay provide examples of estuaries in good health, in catchments which are more developed," Thomas said.
"They have large extensive seagrass and cockle beds that are important for ecosystem health.
"The state of an estuary is a reflection of land use practices throughout the river catchment from both current and historic land use. Estuarine health can be impacted by land use such as forestry, intensive agricultural practices, urbanisation, and water discharge practices.
"The monitoring results help the Council understand trends in estuarine health to inform catchment management, but equally the results also determine whether land use activities impacting on estuaries are being managed effectively."
The estuary state of the environment monitoring programme was currently being extended and reviewed to ensure the data was as robust as possible.