One of the most significant threats to an estuary is human intervention through river mouth openings.
If the river mouth is opened when conditions in the estuary are not quite right mass fish kills can occur. Less obvious impacts include the flushing of fish eggs and larvae out to sea.
Before an artificial river mouth opening can occur Glenelg Hopkins CMA, under the Water Act (1989), MUST issue a Work on Waterways permit to the relevant land manager and all conditions of the permit must be met. This lowers the risk of damage to estuarine biodiversity.
Artificial river mouth openings are only to be carried out by the responsible land manager with authorisation from Glenelg Hopkins CMA. Any one found to have contributed to an unauthorised river mouth opening will be prosecuted under section 295 of the Water Act (1989) and face fines of up to $20,000 and 10 years imprisonment.
Under statewide protocols the Environment Protection Agency is the control agency for all fish kill-related incidents.
Therefore all initial reports need to be forwarded to this number - 1800444004.
The CMA is support agency and can assist with such activities as site inspections and water quality testing if requested by the EPA.
For fruther information see the WATERWAY INCIDENT (FISH DEATH) RESPONSE GUIDELINE
The Estuaries and estuary management DVD provides a 12 minute insight into the complexity of these ecosystems.