NSW Department of Primary Industries Fisheries Officers are investigating ongoing attempts to illegally open Intermittently Closed and Open Lakes and Lagoons (ICOLLS) on the NSW south coast, which has the potential to lead to large scale fish kills.
DPI A/Director Fisheries Compliance, Brett Andrew, said fisheries officers were recently alerted to several attempts to artificially open Little Lake, in Narooma.
“ICOLLs open and close to the ocean naturally in a constant but irregular cycle,” Mr Andrew said.
“Currently, the water level in Little Lake is high. This has caused concern for some lakefront property owners and local residents.
“When there is sufficient water flowing into the lake or lagoon from the catchment area (usually following heavy rainfall), water levels in the ICOLL will rise.
“Eventually the water in the ICOLL will spill over the entrance sand berm and drain to the ocean. The force of the backed up water then quickly scours an entrance channel through the beach and reopens the ICOLL to the ocean.”
Mr Andrew said ICOLLs close when the ocean waves and tides push sand from offshore into the entrance, which gradually closes the entrance channel. Without further large freshwater flows into the estuary from the catchment, the ICOLL will remain closed to the sea.
“Opening ICOLLs artificially without permit is illegal as it can lead to large scale fish kills caused by sudden drops in water levels and dissolved oxygen levels as well as increased exposure and death of aquatic vegetation which can cause odours.
“Most ICOLLs have existing opening protocols in place, these are developed after extensive consultation with council, the community and government agencies. They are designed to protect infrastructure and residents from flooding, while still protecting the unique environmental values of these systems.
“DPI Fisheries Compliance and Eurobodalla Shire Council are working together to repair the attempted illegal opening to mitigate any negative environmental impacts and investigations are underway to identify the person/s responsible.”
The maximum penalty for carrying out dredging works (such as digging to open an ICOLL) without a permit is $110,000. Illegal fishing activity can be reported via https://www.dpi.nsw.gov.au/fishing/compliance/report-illegal-activity
Little Lake is one of estimated 70 Intermittently Closed and Open Lakes and Lagoons (ICOLLs) on the NSW coast.
Where possible, ICOLLS are left to open naturally. Councils can get permission to artificially open an ICOLL if there is an existing pressure from flooding or to avoid the likely threat of flooding to infrastructure.