Algal Blooms in Port Phillip Bay
What are algal blooms?
Blooms are concentrations of tiny floating marine plants called marine micro-algae (phytoplankton).
Sometimes mistaken as an oil spill or other pollution event, algal blooms can look like a murky, sludge-like substance floating in marine waters and washing onto beaches.
Water affected by a bloom can be temporarily discoloured and have an unpleasant smell. Blooms can vary in colour and may include red, pink, white, green or brown and may change through the course of a bloom.
Blooms occur naturally under certain conditions, including higher levels of nutrients in the water combined with warm weather or light winds. This helps the rapid growth of tiny algae that are normally present at much lower levels.
Port Phillip Bay blooms
Algal blooms in Port Phillip Bay often develop in the days or weeks following heavy rain or warm weather or light winds. They are generally localised and last only for a few days. They can dissipate as quickly as they emerge, being rapidly broken up and dispersed in rough weather. Algae may not always wash up on beaches as it can be broken up in rough deep water away from the shore.
In comparison with other areas around the world, the occurrence, size and duration of algal blooms in Port Phillip Bay are relatively low.
There can be several varieties of algal blooms that may occur in the bay. Algal blooms that are harmful to swimmers or other recreational users have not been reported in Port Phillip Bay.
Some species of algae that can produce toxins have been found in the bay and these can concentrate in shellfish. Commercial fish and shellfish harvested from the bay are subject to quality assurance programs. This includes active monitoring of the commercial shellfish harvesting areas located within the bay, providing assurance that commercial shellfish are fit for human consumption.
Marine algal blooms occurring in the bay are not the same as toxic blue-green algae that occur in Victoria's lakes, dams and rivers. Blue-green algae do not grow in the salty marine waters of the bay. For more information about blue-green algae visit the blue-green algae page on DEPIs website.
A handy reference guide on algal blooms in Port Phillip Bay is available here:
What you should do
Some algal blooms may cause skin irritation and people are advised to avoid water that looks murky or sludgy and wash thoroughly with clean water if coming into contact with it. This applies for pets also.
Use Beach Report (www.cleaneryarrabay.vic.gov.au/beach-report) to find out more about water quality at bay beaches and make good choices about using Port Phillip Bay for recreation. This website will also provide information about current marine algal blooms in the bay.
Report suspected algal blooms, discoloured water or floating slicks to the Environment Protection Authority (EPA) on 1300 372 842.
Anglers are advised not to eat fish or shellfish from an affected bloom area, or those that look unhealthy, have lesions or are found dead.
There are also rules in place about taking shellfish in Victoria – for more information visit: www.depi.vic.gov.au/fishing-and-hunting/recreational-fishing
What is Government doing about algal blooms in Port Phillip Bay?
The Victorian Government has developed a Port Phillip Bay Algal Bloom Response Protocol (available below). The aim of this protocol is to ensure that government is timely in responding to algal events and can provide the community with accurate, up to date information.
In the event that an algal bloom is detected in Port Phillip Bay, this website, and the government's new water quality information website, cleaneryarrabay.vic.gov.au, will provide up to date information on the incident.
Over the summer, you can also check EPA's beach report (at cleaneryarrabay.vic.gov.au/beach-report) which provides daily updates on the water quality at 36 of the bays most popular beaches. The Victorian Government's focus is on identifying blooms and providing clear advice and information to waterway users, coastal land managers and the community on how to identify blooms and what needs to be done to protect their health and the health of their families and pets.
The Department of Environment and Primary Industries (DEPI) is the lead agency in coordinating the response to marine algal blooms in Port Phillip Bay. In most cases EPA will lead the initial investigation of reports of slicks, discoloured water and similar water quality issues and will hand-over to DEPI if confirmed as an algal bloom. Water quality issues in the bay can be reported to EPA on 1300 372 842.